Wood Finishing Training Program

Wood Finishing Training Wood Finishing Training ProgramProgram

Markets, Needs, Prospecting and Supporting the Wood Finishing

Industry

By Michael V Michalski Copyright 2001

Wood Finishing Training Wood Finishing Training ProgramProgram

The Markets

Kitchen Cabinet Kitchen Cabinet MarketMarketThis industry is divided into several different market segments Low End - High Production

Medium Quality - Medium to High Production

High Quality - Medium to High Production

Custom Cabinets - High Quality - Low Production

Cabinet Doors - Medium to High Production & Quality

Note: Some companies have different divisions or lines for the different markets

Low End - High ProductionLow End - High Production

This type of manufacturer is usually selling to mass merchandisers or low cost housing developers.

Application technology can be manual or automatic with the trend being automatic to reduce labor costs.

Coating material tends to be low cost lacquers and pigmented finishes.

Key to selling to this customer is significant material savings, improved finish quality without negative impact on productivity.

Medium Quality - Medium to High Medium Quality - Medium to High ProductionProduction

This type of manufacturer is also selling to mass merchandisers and medium priced housing contractors.

The application equipment may be manual or automatic with the trend towards automatic.

The coatings tend to be pre-catalyzed or UV with a trend towards post catalyzed and UV.

Key to selling to this customer is improved finish quality with no negative impact on productivity and significant material savings.

High Quality - Medium to High High Quality - Medium to High ProductionProduction

This type of manufacturer has their own stores or dealers and may supply high end housing contractors.

The application equipment is usually a combination of manual and automatic with a trend towards automatic.

Coatings tend to be high quality spray or wiping stains, glazes, and pre or post catalyzed with a trend towards post-catalyzed.

Key to selling this customer is improved finish quality, with some improvement in material savings and no loss of productivity.

Custom CabinetsCustom CabinetsThese will vary in both the size of the organization and the quality of their products.

Application equipment is usually manual

Coatings can vary from low cost pigmented materials and lacquers to high quality post catalyzed materials.

Key to selling is improved finish quality and improved efficiency.

Cabinet Door ManufacturersCabinet Door ManufacturersThese will vary in both the size of the organization and the quality of their products.

Application equipment can be manual or automatic with a trend towards automatic.

Coatings can vary from low cost lacquers and stains to high cost post catalyzed and UV.

Key to selling this customer is improved finish quality, with some improvement in material savings and no loss of productivity.

Furniture ManufacturingFurniture Manufacturing

The Wood Furniture market is more diverse than the Kitchen Cabinet market because of the greater diversity of products.

These companies can vary greatly in size, quality and product offering.

In general they are divided into two main groups, Home Furniture and Office Furniture.


Home Furniture companies may focus on a single product group like chairs or tables or may focus on a particular room such as bedrooms or may offer all household furnishings.

Office furniture companies may also focus on a single product group such as desks or may offer a complete line of office furnishings.

In general, these markets are further defined as knock-down or pre-assembled. case goods

The majority of knock-down furniture is finished via automatic finishing systems whereas the majority of pre-assembled furniture is done both manually and automatically.

However, even pre-assembled furniture manufacturers are using more automatic systems to do as many parts as they can before assembly.


Home FurnitureHome Furniture

In general there are more finishing steps in furniture finishing than kitchen cabinet manufacturing.

Furniture is a much more complex substrate than cabinets and therefore more difficult to finish.

In my opinion, this may be one reason why many companies still use HVLP guns instead of Airmix or A/A technology. The more complex the part the more control the operator may need. (feathering)

Home FurnitureHome FurnitureThe Home Furniture market requires a the highest finish quality and is much more labor intensive than any of the other major wood finishing markets.

To sell to this market it is essential that you understand the coatings, the processes, the equipment and the compliance issues.

For most large furniture plants it is important to work with finishing management, safety &environmental personnel and purchasing.

Like Home Furniture, Office Furniture manufacturers can vary greatly in size, quality and product offering.

They too are divided into two major groups, knock-down or pre-assembled case goods.

However, unlike home furniture, many office furniture manufacturers are using automatic equipment for both knock-down and pre-assembled.

Office FurnitureOffice Furniture

Manual equipment is still used but the trend is more towards automation. Manufacturers are pre-finishing the components on flat-line systems before assembly.

Automatic systems and UV coatings are key to offsetting the low labor costs from overseas competitors and is an area that we should be focusing on.


For the most part, the office furniture industry uses similar processes and equipment as the kitchen cabinet industries but with less variety of finishes.

The key to selling to these accounts is the same , namely improved finish quality with reduced material costs with no reduction in productivity.


These industries include such products as doors, windows, molding and paneling.

For the most part they use similar coatings, processes and equipment as the furniture & kitchen cabinet industries.

They use both manual and automatic spraying equipment and many use paint by length machines,

In general Airmix is the desired application equipment but HVLP is also used, especially on NGR stains.

Architectural MillworkArchitectural Millwork

Like the furniture and kitchen cabinet industries, the key to selling to these customers is understanding their main issue or issues. This industry is moving towards more multi-step finishes.

Productivity and finish quality are paramount.

Improved efficiency is desirable but not at the expense of quality or productivity.

Architectural MillworkArchitectural Millwork

This industry tends to use more pigmented materials than clear coats but that depends on the companies current projects or contracts.

The use of2k, high solids primers and pigmented top-coats are typical. The materials tend to need more than 10-1 pressures and may be highly abrasive.

I usually recommend a 20-25 at a minimum and Flowmax pumps when possible.

Store Fixtures & DisplaysStore Fixtures & Displays

Depending on the amount of 2k materials being used this industry is a good candidate for the PU2200 for the primer and some top-coats.

Some companies use polyester and here the Poly-Pump, the PU2120 or the PU2200 may be desirable.

However be careful of pot-life issues. Mix at the gun set-ups are recommended for short pot-life materials.

Store Fixtures & DisplaysStore Fixtures & Displays

Meeting the Customers Needs

When selling to these accounts it is important to address as many needs as possible. In many cases the companies may not be aware of their needs so it will be up to you to discover them.

Here is where you perform a free audit of the customer’s entire finishing process and look for cost reducing opportunities.

By offering these free audits you are apt to uncover the needs of the customer.

Meeting the Customers NeedsMeeting the Customers Needs

To uncover the whole picture I usually try to talk with at least one finisher, one supervisor and someone from the maintenance department and someone from the environmental & safety department.

In this way, you can usually find at least one selling opportunity to get you in the door.

Meeting the Customers NeedsMeeting the Customers Needs

Once you have identified the customer’s needs it is important to try to put a cost for each need.

This may take some effort on your time and the customer’s time, but it will help you to close the deal.

Try to document as many savings areas as you can so that you can use them in your ROI.

Uncover the CostUncover the Cost

During the demo be sure to point out as many savings opportunities as you can to the customer.

After a successful demonstration, be sure to include all the benefits in your proposal along with the ROI.

If you do not provide this information in the proposal, the decision maker may not have enough information to make a purchase decision. .

Address the PainsAddress the Pains

Make sure the equipment is operating correctly before installing and spend the time up front by training the operator and the maintenance personnel.

This will reduce unnecessary call backs which gives you more time to sell..

Ensure A Successful Start-UpEnsure A Successful Start-Up

It is important that the distributor follows up during the first few days to make sure the equipment is operating properly and to ensure that the operators are using the equipment correctly. Address any questions and issues that arise,

Post-Sale Follow UpPost-Sale Follow Up

To sell effectively to the wood market it is important that you know as much about the wood finishing industry as possible.

One way of helping your distributors to be more valuable to the end user is to make them more knowledgeable.

The following slides are presented to help you accomplish this goal.

Be A Valuable ResourceBe A Valuable Resource

Operator Training ProgramOperator Training Program

By Michael V Michalski Copyright 2001

NOTICE

The following slides contain text, graphs, charts, pictures and photographs that are protected under U.S. copyright laws and may not be used, copied, redistributed or sold without the express written permission of the owners of the copyrights.

Atomization Atomization TechnologiesTechnologies

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AtomizationAtomization

Atomization of coatings is defined as a process that reduces the liquid stream of coating into fine spray particles, so that the coating can be applied to a substrate in a relatively controlled manner, for the purpose of achieving a protective, adherent or a decorative film on the surface of the substrate.

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Finish Quality And AtomizationFinish Quality And Atomization

Although insufficient atomization will affect finish quality and cause “orange peel”, finish quality is not solely dependent upon atomization.

It is possible to over-atomize coatings, resulting in excessive overspray and “dry spray”.

Over-atomization causes some of the solvents to evaporate too quickly. This results in dry particles and the inability of the coating to “flow out”.

The use of excessive pressures can separate the liquids from the solids in the coating. This is referred to as “over shearing” or “dry spray”..

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Types of AtomizationTypes of Atomization Air Spray High Volume Low Pressure (HVLP) & (LP)

Airless Spray Air Assisted Airless Spray (A/A) Electrostatic Liquid & Powder

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Other Finish Quality FactorsOther Finish Quality Factors

Aside from atomization, the other issues that can affect finish quality are as diverse as those that affect transfer efficiency.

Surface preparation, humidity, compressed air quality, product handling, dust and overspray can all contribute to a poor finish.

When evaluating application technology, a manufacturer should consider all of these issues.

A technology that offers better atomization may create more overspray, turbulence and dust as a direct result of its atomization process, resulting in overall poor finish quality.

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Conventional air spray is defined as “a spray coating application method in which the coating is atomized by mixing it with compressed air and applied at an air pressure greater than 10 pounds per square inch (gauge) at the point of atomization.”

Air Spray AtomizationAir Spray Atomization

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Air Spray GunAir Spray Gun

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Air Spray & HVLP AtomizationAir Spray & HVLP Atomization

Air Cap

Fluid Nozzle

Fluid

Needle

Fan Air

Atomizing Air

Pattern

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Air Spray PatternAir Spray Pattern

Shot Stroke

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Air Spray Pattern Cross Air Spray Pattern Cross SectionSection

1 Mil

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Air Spray GunsAir Spray Guns

Air Spray guns guns offer finishers a great deal of flexibility or control over many aspects of the atomizing process. These aspects include the almost infinite adjustment of the fluid flow, full spectrum spray pattern adjustment and with a built in air valve, full atomizing air pressure adjustment. The use of external regulators can also perform some of these aspects. Air Spray guns also have the greatest flexibility when it comes to coatings. They can spray just about anything.

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Although these guns are inexpensive to purchase and maintain, these guns are the most expensive to operate in terms of the amount of coating they use compared to more efficient technologies. Even though the atomization can be very fine from these guns, the excessive overspray, bounce back and turbulence they create can cause numerous finish quality problems. In a dusty finishing environment like a small cabinet shop, the excessive air pressure from these gun can kick up sanding dust and deposit it on the substrate.

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Air Spray guns are the least efficient spray technology and therefore are illegal to use in various industries in many states. The use of these guns is severely limited in other states for touch up, repair and other specified uses. Air Spray guns are usually less than 30 % efficient and consume moderate to high amounts of compressed air as well.

HVLP AtomizationHVLP Atomization

In Pennsylvania the Department of Environmental Protection defines HVLP guns as “The application of a coating by means of a gun which operates between 0.1 and 10.0 psig air pressure.”

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HVLP AtomizationHVLP Atomization

In other state regulations HVLP atomization is defined as being “a spray coating application method in which the coating is atomized by mixing it with compressed air and applied at an air pressure of 10 pounds or less, per square inch (gauge) at the point of atomization.”

Both conventional Air Spray and HVLP are air atomizing technologies! The only difference is in the amount of air pressure they use and sometimes the cfm.

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Shot

HVLP PatternHVLP Pattern

Stroke

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HVLP Pattern Cross SectionHVLP Pattern Cross Section

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Principle of HVLP Principle of HVLP

An HVLP gun is an air spray gun with a unique difference. The difference is the resulting lower particle spray velocity that occurs when more cubic feet per minute (CFM) of compressed air are used to atomize the coating rather than more pounds per square inch (PSI) of compressed air, compared to an air spray gun. In an Air Spray gun, these values are reversed.

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In general, an air spray gun uses more pressure and less air volume of compressed air whereas an HVLP gun uses more volume and less pressure at the air cap to atomize the coating. This fact which directly affects particle spray velocity and therefore transfer efficiency is the only difference between Air Spray technology and HVLP technology. The efficiency of these guns is normally much higher then air spray and can range from 55 to 75%. These guns consume high to very high amounts of compressed air.

Principle of HVLP Principle of HVLP

Limits of HVLP Limits of HVLP

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Although HVLP technology continues to improve, this technology is limited by two major factors that affect finish quality, coating viscosity or high solids coatings and flow rates or productivity. Either one of these factors can result in unacceptable finish quality which then limits the manufacturer to using lower solids or viscosity coatings, which usually means higher VOC coatings, or the manufacturer might try to compensate by increasing the atomizing air pressure beyond 10 psi, resulting in lower transfer efficiency.

HVLP GunHVLP Gun

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HVLP Air Cap Test GaugeHVLP Air Cap Test Gauge

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HVLP Air Cap Test GaugeHVLP Air Cap Test Gauge

Manufacturers that must use HVLP guns must have a test gauge air cap available for inspectors to use to verify that the guns are being operated at 10 PSI gauge or less, at the air cap.

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HVLP GunHVLP Gun

Again, an HVLP gun is in essence, an air spray gun. The physical difference is that the air passages in the gun may be larger than those in an Air Spray gun and usually contain a restrictor that converts the high atomizing air pressure (PSI) to low pressure. The air holes in the air cap are also significantly larger to allow greater volume of air (CFM) to pass through them. Spray particle velocity is significantly decreased resulting in higher transfer efficiency than conventional air spray guns. These guns are limited by viscosity and speed. They also use more CFM than conventional guns.

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Principle of Airless Atomization Principle of Airless Atomization

Airless atomization is created by the use of a pump that pressurizes the coating to fluid pressures in excess of 1000 psi and usually, to pressures from 2000 psi to 3000 psi. This process is also referred to as hydraulic atomization. The high fluid pressure is allowed to escape to atmospheric pressure from the gun by means of a tungsten carbide fluid tip or orifice, that is cut in such a way as to form a a elliptical spray pattern of fixed width. The flow rate is also determined by the size of the orifice and is affected by viscosity and fluid pressure.

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Airless Fluid PatternAirless Fluid Pattern

Shot Stroke

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Airless Pattern Cross SectionAirless Pattern Cross Section

1 mil

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Airless GunAirless Gun

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Airless SprayingAirless Spraying

Airless spraying has some distinct advantages over Air Spray. Airless has less bounce back and overspray, is capable of of spraying higher viscosity or higher solids coatings and is much faster than Air Spray. Because of it’s course atomization and the lack of controllability by the operator and the heavy edges that are inherent in Airless atomization this technology is not considered by many in the industry to be capable of fine finishing such as furniture.

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Although heating the coatings helped improve Airless finish quality, there was still the issue of controllability of the gun. When an Airless gun is triggered there is a recoil which can affect part to gun distance and therefore affect finish quality. Even with the advent of fine finish Airless tips and other pre-orifice technologies, Airless still has a problem in that the pattern tends to be heavy at the ends which can create stripes or lines in the finish.

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There are several different types of Airless pumps available including electric, pneumatic and hydraulic. Only the pneumatic pumps consume compressed air. The hydraulic and electric consume electricity. CFM consumption is low compared to other technologies as there is no air used by the gun for atomization. This reduces the potential for air contaminants in the finish but the transfer efficiency is only 40 to 50%.

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Air-Assisted AirlessAir-Assisted Airless

Air-Assisted Airless is a hybrid of Air Spray and Airless. It uses fluid pressure like an Airless to do most of the atomization and some atomizing air like an Air Spray gun to eliminate the heavy edges of the Airless pattern and enhances atomization. The result is the production and viscosity or high solids capability like an Airless with more operator control and a finish quality closer to Air Spray but with less overspray.

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Air-Assisted Airless Pattern Air-Assisted Airless Pattern without Atomizing Airwithout Atomizing Air

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Shot Stroke

Air-Assisted Airless Pattern Air-Assisted Airless Pattern with Atomizing Air Onwith Atomizing Air On

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Shot Stroke

Air-Assisted Airless CrosscutAir-Assisted Airless Crosscut

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Electrostatic Application EquipmentElectrostatic Application Equipment

The electrostatic spray process operates on the principle that opposites attract. A negative electrical charge is applied to the atomized paint particles.

These electrostatically-charged paint particles are attracted to the positively grounded surface of the substrate being finished.The use of electrostatic in wood finishing is limited to very high production facilities.

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Electrostatic GunElectrostatic Gun

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Electrostatic PrincipleElectrostatic Principle

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Electrostatic SystemElectrostatic System

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Types of Electrostatic Application EquipmentTypes of Electrostatic Application Equipment

Air Spray Bells

HVLP Disks

Airless Powder

Air-Assisted Airless

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Electrostatic AtomizationElectrostatic Atomization

Electrostatic application technology is available in various atomization formats such as air spray electrostatic and airless electrostatic.

The atomization process that they use is the same process as their non-electrostatic counterpart, but the atomization is enhanced by the use of high voltage.

As the paint particles pass through the high voltage field, the paint particle’s molecules become charged causing them to become excited and repel from each other.

This is referred to as electrostatic atomization.

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Disks and BellsDisks and Bells

Disks and bells use centrifugal forces from a rotating disk combined with some assistance from electrostatic atomization.

High speed rotation and serrated edges on the disks help pre-atomize the particles prior to the electrostatic atomization.

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Electrostatic BellElectrostatic Bell

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Powder Coating on WoodPowder Coating on Wood

Powder coating on wood is already a reality in some manufacturing facilities. The technology is similar to liquid electrostatic applications and subject to many of the same issues such as grounding. For now, the use of powder has been mostly limited to MDF but the future of powder should not be ignored. Powder coating for wood will combine the use of high temperature infrared to get the powder to gel and may be combined with Ultra-Violet (UV) for even faster curing. The moisture content of woods and the powder’s ability to flow out smoothly are current limitations of this technology.

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Common Wood Common Wood ApplicationsApplications

Adhesives Typically adhesives are applied using a conventional gun for flammable solvent based adhesives. For non-flam we recommend the use of the stainless steel, conventional gun. For water base adhesives that atomize into fine particles and create overspray, we recommend the use of the HVLP gun. The fluid nozzle should be sized for the speed at which the adhesive is to be applied. Normally a number 0.60 nozzle will suffice but some users like the speed of the number 0.72 nozzle.

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Adhesive ApplicationsAdhesive Applications

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HVLP

Air Spray

LVLP

Pressure Pots

Diaphragm Pump

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Sap Sealers, Toners, Glazes, Shading & Stains

For very small quantities we recommend the use of the HVLP gravity gun. For small shops an HVLP pressure gun with a 2-quart pressure cup is recommended. Larger shops can also use the HVLP pressure gun but with a pressure pot or a low pressure pump. Very high production shops should use Air-Assisted Airless for wiping and HVLP for spray stains. Some very large shops use Air-Assisted Airless for their spray stains.

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Stain SystemsStain Systems

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Common Wood ApplicationsCommon Wood Applications

Primers, Sealers & Topcoats

Small shops can use an HVLP pressure gun with a 2-quart pressure cup. Medium production shops can use a large pressure pot or a low pressure pump with an HVLP gun. For manufacturers who want to improve finish quality, reduce overspray and improve productivity, we recommend the Air-Assisted Airless system. Tip size will be based on the finisher's preference for speed. Fluid pressure will depend upon the desired finish quality, speed and viscosity of the coating.MM

Sealers & Top Coat SystemsSealers & Top Coat Systems

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Latex Coatings

These coatings can be applied with any technology. Traditionally Airless is the common application method, however for most architectural wood applications, the latex can be reduced to spray with any technology. Airmix requires less reduction than HVLP. A high pressure A/A or Airmix® system handles latex applications better than a medium pressure system.

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High Solids or Latex High Solids or Latex Application SystemsApplication Systems

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Finishing Finishing Department Department

Operator Training Operator Training ProgramProgram

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Finishing Department Training Finishing Department Training OutlineOutline

1. Checking the Coating:

- Viscosity

- Temperature

- Agitation & Circulation

- Straining & Filtering

- Recordkeeping

Example

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2. Selecting the spray system:

- Selecting the Fluid

Delivery System

- Selecting the Spray Gun

- Selecting the Correct Setup

- Selecting the Correct Hoses

Training Outline continuedTraining Outline continued

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Example

3. Setting up for Spraying:

- Checking the Air Supply

- Setting the Fluid pressure

- Checking Fluid Flow Rates

- Setting & Checking the

Atomizing Air Pressure

- Pattern Uniformity & Width

Training Outline Training Outline continuedcontinued

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Example

4. Spraying Technique:

- Gun to Part Distance

- Targeting

- Gun Angle

- Gun Speed

- Triggering

- Overlapping & Box Coating

5. Checking The Finish:

- Mil Thickness

- Finish Quality

- Touch-up


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Example

6. Flushing & Cleaning Procedures:

- Flushing & Line Cleaning Procedure

- Color Changing Procedure

- Gun Cleaning Procedure

- Solvent Use Recordkeeping

7. Parts Wash-off Procedure

- Parts & Solvent Recordkeeping

- Rag Disposal


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Example

8. Fluid Handling:

- Storage

- Waste Disposal

9. Equipment Maintenance:

- Leak Inspection & Maintenance Plan

- Gun Leak Inspection & Maintenance

- Pump Leak Inspection & Maintenance

10. Booth Maintenance

- Filter Replacement & Disposal

- Checking the Manometer

- Booth Cleaning, Coating & Recordkeeping

11. Safety Codes and Regulations


Example

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Checking the CoatingChecking the Coating

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CoatingsCoatingsA coating is a liquid composition that converts to a solid film after it is applied to a substrate for protective, adherent or decorative purposes.

For wood finishing the most commonly used coatings are stains, sealers and top coats. These coatings can be solvent based, waterbased, pre-catalyzed or post-catalyzed and UV.

Before attempting to use application equipment it is important to understand some basic fundamentals about coatings and finishing.

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Checking The CoatingChecking The CoatingIn order to achieve a consistent finish quality it is crucial that the coating also be consistent. For this reason we start the finishing process by checking the coating. If you want the same results coming out of the gun you must have a consistent coating going into the gun. Note the lot and batch numbers for each container of coating when you open it and note your findings on a coating quality check form. By keeping good records you can quickly identify and track problems later, if needed. You may also be able to prevent finishing problems before they occur, eliminating costly rework and VOC emissions.

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ViscosityViscosity

Viscosity is a physics property of fluids and is a measure of the internal friction of fluid and its resistance to flow. In general, it is a measure of a coatings thickness.

As the temperature of any coating affects viscosity, any measurement of a coating’s viscosity should be done in relation to its’ temperature.

In general the temperature used when measuring viscosity is 70 degrees Fahrenheit.

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Viscosity CupsViscosity Cups

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There are many different types of viscosity cups available. Zahn, Ford, Fischer and Afnor to name just a few.

Viscosity cups are also numbered. This is to allow for more accurate readings for the diverse fluids that need to be measured.

It is recommended that you sue a cup in which your coating’s viscosity is within the middle of the range for that cup.

Afnor CupAfnor Cup

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Viscosity Conversion ChartViscosity Conversion Chart

Centipoise Zahn2 Afnor (CA4) 20 18 sec. 12 sec. 25 19 14 30 20 16 40 22 20 50 24 25 60 27 29 70 30 32 80 34 34 90 37 37 100 = 1 Poise 41 40

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Poise, Centipoise & Kreb’s Poise, Centipoise & Kreb’s UnitsUnits

Poise is an other method of measuring viscosity. In this method viscosity is measured by the amount of resistance the fluid has when a ball of specific size and weight is passed through it. Centipoise is 1/100 of a Poise.

Krebs Units (KU’s) is yet another method of measuring viscosity. In this method, viscosity is measured by the resistance of the movement of a device, such as a paddle, in a rotary motion.

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Additional Viscosity ConversionsAdditional Viscosity ConversionsCentipoise Poise Zahn #2 Ford 3 Ford 4 KU's Afnor

10 0.1 16 5

15 0.15 17 8

20 0.2 18 12 10 12

25 0.25 19 15 12 14

30 0.3 20 19 14 16

40 0.4 22 25 18 20

50 0.5 24 29 22 30 25

60 0.6 27 33 25 33 29

70 0.7 30 36 28 35 32

80 0.8 34 41 31 37

90 0.9 37 45 32 38

100 1 41 50 34 40

120 1.2 49 58 41 43

140 1.4 58 66 45

160 1.6 66 50

180 1.8 74 54

200 2 82 58 52MM EXEL-NA

Measuring ViscosityMeasuring Viscosity

Viscosity can be measured by the time required for a given volume of coating to flow through a small hole in the bottom of a viscosity cup at a specified temperature.

There are many other ways to check viscosity. Some of the more commonly used methods are briefly explained on the following slides.

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Viscosity MeasurementViscosity Measurement

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How to Check ViscosityHow to Check ViscosityBefore checking any coating for viscosity, it may be recommended by your material supplier to allow the coating to achieve a specific temperature or your ambient temperature. Agitation or shaking may also be required. With multiple component coatings such as epoxies and urethanes, it is a good idea to check each component before and after mixing. Checking viscosity can save you costly rework and eliminate unnecessary VOC emissions from rework.

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How to Check Viscosity How to Check Viscosity

Make sure your viscosity cup is absolutely clean. Never use anything hard to clean the hole in the bottom of the cup. These holes are precision machined and any distortion of this hole will invalidate your viscosity measurement.

Place the cup into the coating until the cup is full. Raise the cup out of the coating and immediately start your stop watch. When you observe a break in the fluid stream when the cup nearly empty, stop your stop watch. The time indicated on the stop watch is your viscosity reading for that cup.

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When to Check ViscosityWhen to Check Viscosity

Viscosity should be checked shortly after it is delivered to your facility. This allows you time to get replacement material before being forced to use it for production which could lead to quality issues and rework. At a minimum, viscosity should be checked for each container of coating that you use, at ambient temperature, before you use it. Be sure to note both the viscosity and the temperature of the coating.

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Viscosity of Liquids& Semi-SolidsViscosity of Liquids& Semi-Solids

Liquids & Semi-Solids CentipoiseAcetone .3

MEK .4

Toluol .6

Water 1

Milk 3

Oil SAE10 65

Oil SAE40 319

Honey 3,000

Ketchup (Heinz) *50,000

Corn Syrup 110,000

Peanut Butter (Skippy) *250,000

Shortening (Crisco) *1,200,000MM

Changing ViscosityChanging ViscosityThere are many ways to change a coating’s viscosity. The most commonly used method is reduction by the addition of solvent. With the imposition of environmental regulations, reduction is not an option in some areas and not environmentally desirable in others.

When reduction is necessary it is crucial that you follow the instructions by your material supplier and that you do not exceed their recommendations. Over reduction increases VOC emissions and may cause coating failure. Write down the type and amount of solvent used.

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Reduction continuedReduction continuedReduction may be necessary in some coating applications such as two, or multi-component coatings. Always use the solvent recommended by your material supplier.

Reduction may also be needed to improve or enhance the finish or needed in order to overcome specific application issues such as blushing on humid days and poor flow out of the coating on cold days. These application problems can be eliminated in other ways however.

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Paint HeatersPaint Heaters

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Heated CoatingsHeated Coatings

One technology that can have a dramatic affect on coating viscosity is heat. As discussed earlier, temperature is crucial when measuring viscosity. It is also useful in reducing viscosity without adding solvent. Aside from saving money from lower solvent use and reducing VOC emissions, the other benefits of heat are also sources of potential cost savings.

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Heat & ViscosityHeat & Viscosity

50 86 122 158 Degrees (F)

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300

200

150

100

50

Centipoise

Temperature

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Heated Circulating Fluid Heated Circulating Fluid Handling SystemHandling System

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Gun

Pump

Heater

Regulators

Siphon Hose

Fluid Container

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Advantages of Heated Advantages of Heated CoatingsCoatings

• Improved Transfer Efficiency due to lower atomizing pressures

•Lower coating usage.

• Lower solvent usage

•All weather spraying due to the elimination of blushing

• Improved hang time on vertical surface

•Improved flow out

• Shorter flash and cure times MM

ShearShearAnother widely used but less commonly known method for reducing viscosity is shear. Shear can be created simply by moving the fluid such as agitation, stirring, pumping and circulating. Much depends on the nature of the coating. Some materials are thixotropic, which means they get less viscous when sheared and some are Reopexic, which means they become more viscous when sheared. “ Over Shearing” can actually separate some of the liquids from the solids resulting in an unacceptable finish .

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Shaking, Agitating, and CirculatingShaking, Agitating, and Circulating

As some coatings are subject to settling, it is usually recommended that the coating be shaken, stirred, agitated, or circulated before checking the viscosity or using it.

This will help ensure that the solids are properly suspended in the liquids throughout the container or system.

Aside from providing a more accurate viscosity sample, this process improves color consistency and coating uniformity.

Check with your coating supplier for specific instructions.

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Straining and FilteringStraining and Filtering

After ensuring that the coating is at the appropriate temperature and viscosity, the next step before using the coating is to strain or filter the coating, if possible.

This will help remove any unwanted contaminants from the coating that could ruin the finish.

Proper filtration also ensures better performance from higher pressure systems that use small fluid tips.

Some coating suppliers may recommend that no filtering be performed or that it be performed before coating reduction.

Check with your coating supplier for specific instructions.

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Fluid Filters & StrainersFluid Filters & Strainers

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Paint Strainers

In-Line Filter

Pump Outlet Filter

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Filter ScreensFilter Screens

Airless Gun Screens or Filter ElementsMM

CourseMedium

Fine

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For most coating applications filtration has substantial benefits. For the most part these benefits include quality finish assurance, increased productivity from reduced downtime, reduced rework from application equipment failure and reduced maintenance costs. Like the oil filter in your car, fluid filtration should play a major part in any finishing process.

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Filter ScreensFilter Screens

Microns & MeshMicrons & MeshWhen considering filtration for your coating you should consult with your material supplier as to just how far you can go. It would not be wise to filter out needed aggregate such as silica or zinc from a protective coating. However, even these materials are pumped through some level of filtration before applying. You need to be concerned about the micron size of the aggregate in relation to the mesh of your filter media. The mesh should be slightly larger then the micron size of the aggregate. If the mesh was smaller, the filter would “pack out” quickly.

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50 Mesh (US Sieve #) = 297 Microns = .011 inches





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Microns & MeshMicrons & Mesh

RecordkeepingRecordkeeping

Depending upon whether or not your company must comply with the new regulations, or other existing regulations, you may be required to keep track of certain operations or procedures . In some cases you may be required to write down how much coating you used that day. If you are reducing coating you may have to write down what kind of reducer you used and how much. If this responsibility is assigned to you, you must be diligent in your recordkeeping.

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The following is a list of records that should be kept, if not for regulatory purposes, then for just good finishing operation management. Your company will inform you of any of these or other recordkeeping responsibilities, if any.

• Coating Check In Log

•Coating Usage Log

• Solvent Usage Log

• Reduction LogMM

RecordkeepingRecordkeeping

Coating Application ChecklistCoating Application Checklist

Coating Name____________ Mil Thickness____________

Viscosity_______________ Number of Coats__________

Flow Rate______________ Pattern Width____________

Fluid Nozzle or Tip_______ Gun Distance_____________

Air Cap_________________ Flash Time______________

Air Pressure_____________ Cure Time_______________

Fluid Pressure___________ Application Technology_____

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Selecting the Selecting the Spraying SystemSpraying System

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Selecting the Fluid Supply SystemSelecting the Fluid Supply System

Many finishers continue to waste coatings, solvent, generate waste and lose productivity by continuing to use pressure pots. Others suffer similar problems by using pumps improperly or that are oversized for their needs. Dedicated pumps generate the least waste. Color change systems also minimize waste. For coating usage of less than 1/2 gallon a day, Siphon or Gravity Cup Guns are recommended.

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Siphon Feed GunsSiphon Feed Guns

Siphon guns are one of the oldest spray technologies. Because of their many years on the market these guns are the most common type of spray guns. As siphon guns rely on the atomizing air to siphon the coating, these guns are usually the most inefficient. This is due to the lack of independent control of atomizing air and fluid delivery. The more fluid you need the higher the atomizing air pressure will have to be. Although siphon guns are available in HVLP, these guns are limited to low viscosity coatings.

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Gravity Feed GunsGravity Feed Guns

Similar to siphon guns, these guns allow for some independent control of the fluid delivery and the atomizing air. However, care must be taken in selecting the right size fluid nozzle. If the fluid nozzle is too small the gun will starve for fluid. Operators may compensate for this by increasing the atomizing air which also increases fluid delivery, but may decrease efficiency. Viscosity is an other issue that should be considered when setting up a gravity gun. These guns are ideal for short color jobs, frequent coating changes, touch up, shading, glazing, staining and for coatings that are too viscous for siphoning.

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Pressure Feed GunsPressure Feed Guns

Pressure feed guns offer the best control of the air spray technologies. These guns allow for the independent control of atomizing air and fluid pressure. The guns come in a variety of air atomizing technologies from conventional to HVLP, The guns can be fed by pressure cups, pressure pots or low pressure pumps. They handle a wide variety of coatings such as adhesives, stains, sealers and top coats. These guns are ideal for most small to medium sized cabinet shops, however they are not as efficient, use more air, are not as productive, create more waste and do not give the finish quality of Air-Assisted Airless.

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Pressure PotsPressure Pots

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Pressure PotsPressure Pots

Kremlin recently introduced the 2.5 gallon, non-ASME, non-stainless steel tank. This low cost pot is good for most solvent based coating applications and works with most low solids, solvent based adhesives. It is not recommended for non-flam, pre-cats or water borne adhesive. Kremlin is planing to release their larger, ASME, stainless steel pots which would handle these other types of coatings as well as solvent based coatings and adhesives. In the mean time we recommend a Diaphragm Pump be used.

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Diaphragm PumpsDiaphragm Pumps

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Wall Mount Pail & Drum

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Low Pressure Diaphragm Low Pressure Diaphragm PumpsPumps

The system can be used for a wide variety of coatings including water base, solvent base, pre and post catalyzed coatings and water, solvent and non-flam adhesives. The unit is available in various mounting configurations including; wall mount, 5-gallon pail mount, 55-gallon cover mount and portable mount.

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Piston PumpsPiston Pumps

Piston pumps are like diaphragm pumps in that they are usually air operated, siphon directly out of 5 and 55 gallon containers and pressurize the coating to deliver it to a gun. All piston pumps have a pressure ratio, which is the relationship of the air motor piston’s diameter to the fluid section piston’s diameter. The larger the ratio, the higher the fluid pressure. For example, in a 10-1 pump, 100 pounds of air pressure into the system yields 1000 psi fluid pressure. A 20-1 pump with the same inbound air pressure would yield 2000 psi.

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Medium Pressure PumpsMedium Pressure Pumps

Portable Wall Pail Cart

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10-1 Pump10-1 PumpThese pumps are a 10 - 1 pressure ratio, stainless steel pump that is normally supplied with dual air regulators, wall mount bracket and a five-gallon siphon hose assembly with an inlet strainer. The pump is capable of supporting 2 - .011 tips at medium pressures but is normally used as a single gun pump with tips up to a .015. The pump is available in various mounting configurations including; wall mount, 5-gallon pail mount, cart mount and stand mount. The unit can be supplied with either a 5 or 55-gallon siphon hose.

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Small 10-1 Pumps Small 10-1 Pumps

Small 10 -1 pumps were designed to be both environmental and user friendly. By using small, but durable fluid sections on the pumps, waste generation from flushing is reduced to one fourth of the waste generated by pressure pots and large 10-1 pumps. The 10-1 models need only eight to ten ounces of fluid to prime and usually less than 16 ounces to flush.

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Small 10-1 Pumps Small 10-1 Pumps These pumps are easier to use than pressure pots. The pumps are air-operated and hook up to any standard compressed air supply. Only four to five cfm are required to run these pumps, which is one fourth of the cfm consumption of HVLP systems. By incorporating a quick acting, efficient pump design downtime is reduced by eliminating the high maintenance fluid regulators used on larger pumps. Maintenance of these pumps is relatively easy and can be performed in the field by in-house personnel.

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Small 10 – 1 Pumps Small 10 – 1 Pumps

To accommodate finishers, these systems were designed to reduce operator fatigue. They use smaller diameter fluid and air hoses that are lighter and more flexible than hoses used on pressure pots and Airless systems. The smaller diameter fluid hoses also reduce clean-up time and waste generation. Complete system flushing is done in as little as one minute. Material handling is greatly reduced as pumps can siphon directly out of containers and can handle higher viscosity materials with less solvent reduction.

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Two Component SystemsTwo Component Systems

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Two Component Operating Two Component Operating PrinciplePrinciple

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Electronic Meter Mix SystemElectronic Meter Mix System

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Control Panel Mix Manifold

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P2-2KP2-2KTwo Component (2K) pump systems reduce waste generation and rework by minimizing the amount of leftover post-catalyzed material left in the fluid supply system and ensuring a consistent viscosity to the gun.

Because the resin and the catalyst are mixed on demand by the pump, the only waste left over is the mixed material in the static mixer, the fluid hose and the gun.

This can reduce waste stream generation as much as 75%.

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P2-2KP2-2KAnother advantage of 2K pump systems is higher transfer efficiency.

The viscosity of the coating feeding to the gun remains consistent. The operator is therefore not prone to increasing atomizing pressure to compensate for viscosity changes.

This improves finish quality, thus reducing rework.

2K pump systems also eliminate the need for forced curing, which saves energy.

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There are many factors which you must consider such as finish quality, productivity, environmental compliance, efficiency or (operating costs), personnel aptitude, your products and your frequency of color or coating changes, when selecting a spray gun. As these technologies were discussed earlier in this course we will not rehash these technologies here. Once you have selected the proper gun, you must make sure it has the proper set up.

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Selecting the Spray GunSelecting the Spray Gun

SELECT THE CORRECT SETUP FOR THE GUNSELECT THE CORRECT SETUP FOR THE GUN

Many finishing issues can be attributed to the improper selection of tips, air caps and nozzles and the failure to properly maintain them or replace them when they are worn out.

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Fluid NozzlesFluid Nozzles

The proper selection of the fluid nozzle is critical to successful use and application of the gun and the coating. If you select too small a nozzle you may starve the gun for fluid resulting in poor flow out of the coating or insufficient speed for the operator. Excessive wear may occur due to operators compensating by using excessive fluid pressure. Using too large a fluid nozzle may result in runs and sags or may contribute to poor atomization. Too large a nozzle may also result in excessive needle wear as operators compensate for high fluid delivery by turning the fluid needle in too far.

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Fluid Nozzle Selection GuideFluid Nozzle Selection Guide

A good rule of thumb for selecting fluid nozzles for customers is to duplicate his existing fluid nozzle size. To do this you will need to find out what the orifice of his nozzle is in thousandths of an inch or millimeters. Also verify that the existing nozzle is not too small or too large for what the customer is doing. To quickly convert Kremlin fluid nozzle sizes to thousandths of an inch, multiply the nozzle number by 4. For example a number 12 nozzle is approximately .048. See chart for exact sizes. The nozzle number is stamped on the nozzle.

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Fluid Nozzle SizesFluid Nozzle Sizes

07 = .028 Very Low Viscosity - Low Flow Rates

09 = .035 Low Viscosity- Low to Medium Flow Rates

12 = .047 Medium Viscosity - Medium Flow Rates

15 = .059 High viscosity - Medium Flow Rates

18 = .071 High Viscosity - High Flow Rates

22 = .087 Very High Viscosity - High flow Rates

27 - .106 Very High Viscosity - Very High Flow Rates

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Nozzle Flow ChartNozzle Flow ChartApproximate Flow Rate (Water)

0

20

40

60

80

100

120

140

Pressure (PSI)

Flow

rate

(oz/

min

)

27 Nozzle

18 Nozzle

22 Nozzle

15 Nozzle

12 Nozzle

9 Nozzle

7 Nozzle

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Fluid NeedlesFluid Needles

All guns are supplied with the appropriate fluid needle that corresponds to the nozzle size. Most needles are specific for each nozzle however, some needles have a range of 2 or 3 nozzles that they will work with. These sizes or numbers, are stamped on the needle. Needles are normally stainless steel.

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Air CapsAir Caps

For the most part, the gun you order will come with the proper air cap. However, care must be taken when reading the charts in the manuals or literature as the gun descriptions are very similar to each other. Usually, the air cap is specific for each type of gun such as gravity, siphon or pressure and for each subset of guns such as LVLP & HVLPVLP. Be sure you check the gun model number and the fluid delivery method. The air cap type is stamped on the face of the air cap.

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Air-Assisted Airless Air CapsAir-Assisted Airless Air CapsThis air cap is designed to use the lowest possible air pressure to eliminate the "tails" from the spray pattern and to enhance atomization. Always set the atomizing air just high enough to eliminate the tails. Atomization is done mostly by the fluid pressure, not the air pressure. There may be some coatings, such as urethanes that may require more atomizing air to minimize solvent popping. Again, use soft objects for cleaning. Air caps should only be soaked in solvent prior to cleaning. The air holes should then be blown out after soaking and cleaning with a soft needle. Be sure to wipe off all residue on the air cap with a solvent laden rag before re-installing the air cap.MM MM

Air-Assisted Airless Air CapAir-Assisted Airless Air Cap

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Air - Assisted Airless TipsAir - Assisted Airless Tips

These tips are designed to allow the atomizing or tail air, to be blended into the fluid stream at the point of atomization as the fluid exits the gun. This is the optimum point at which air should be introduced, to use the least amount of air pressure possible and to minimize forward spray particle velocity and turbulence. The fluid tip is constructed of brass or stainless steel with a tungsten carbide insert. Most manufacturers’ tips are cut in a way as to deliver an elliptical pattern similar to conventional guns.

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Air – Assisted Airless TipsAir – Assisted Airless Tips

Old Style New Style

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TipsTipsThe amount of fluid a tip can deliver is based on viscosity and pressure but is mostly controlled by the size of the hole in the tip. The larger the tip sizes the higher the flow rate. All tips are cut at specific angles, which determines the degree of the spray angle. It is therefore necessary to understand the tips’ identifying numbers and cross reference that with the manual to select the right speed and width of pattern that meets your needs.

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TipsTips

Selecting the right tip size and the degree of the spray pattern angle are crucial to the overall efficiency of your system. Selecting a tip that puts more coating on the part then is necessary is wasteful and costly. Using a spray pattern that is a lot wider than the part is inefficient. Tips should be chosen specifically for the part geometry you are finishing,

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Airless TipsAirless Tips

Airless tips are similar to Air-Assisted Airless tips in that they are constructed of similar materials, have pre-determined spray pattern widths and flow rates. The flow rates for these tips would be significantly higher than Air-Assisted Airless tips of the same orifice size as the fluid pressures used are substantially higher with an Airless gun.. Another unique feature of some Airless tips is that they are reversible which allows the plugged tip to be blown out by reversing the tip and triggering the gun.

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Airless TipsAirless Tips

Flat Tip Twist Tip

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Airmix® Tip MaintenanceAirmix® Tip Maintenance

Never clean the tips with any hard object such as metal brushes or hard pins or needles. Kremlin has nylon brushes and special soft stainless steel unclogging needles for tip cleaning. The tip seal or filter seal is in the back of the tip and seals the tip against the fluid outlet on the head of the gun. This seal becomes compressed with frequent use and should be replaced regularly. Once a month is usually recommended.

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Air-Assisted Airless & Air-Assisted Airless & Airless Tip WearAirless Tip Wear

Air-Assisted Airless tips and Airless tips, are subject to wear as abrasive fluids pass through them at high pressures. The wear on the tips can distort their original spray pattern and therefore their uniform film build. As tips wear their flow rates can increase dramatically leading to increased material consumption and VOC emissions. More paint on the part then is specified is more costly than maintaining the tips. Manufacturers should monitor their flow rates from any spray gun, but as flow rates are dramatically affected by the tips orifice size, it is recommended that these technologies be checked more frequently. MM

In-Line Filter & ScreensIn-Line Filter & Screens

These filters are designed to remove particles of dirt and coating that might cause the tips to plug. The standard filter is 85 mesh for number 09 tips and larger. For number 06 tips and smaller, use the 140 mesh filter. The filter screen should be removed and cleaned by soaking, brushing and sometimes blowing. A filter that is just flushed is not properly cleaned. The flush solvent goes through the open areas of the screen. Over time, the screen will become clogged and the gun will lose volume and pressure thus effecting atomization.

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In-Line Filter & Screen In-Line Filter & Screen Maintenance Maintenance

Start with checking daily and then decrease the frequency of checking until a standard for that application is achieved. If the screens are loading up several times a day, you may need to add a super-filter to your system or you might be using a screen that is too fine for your coating. Keep in mind that if you go to a larger mesh screen you might plug your tip. The screens are available in various meshes to match the tip selected. Small orifice tips should use higher mesh screens. See the catalog or part sheet for specific recommendations.

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SELECTING THE CORRECT HOSES FOR SELECTING THE CORRECT HOSES FOR YOUR SYSTEM YOUR SYSTEM

Many users continue to use the old standard air and fluid hoses because they have always used those hoses. Some hoses can effect atomization, ergonomics and waste. The proper selection of both the air and the fluid hoses are critical to the performance of any system.

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Air HosesAir Hoses

It is recommended that you use 1/4" or 3/16" I.D. air hose for Air-Assisted Airless as the guns use very little air and we want to keep the guns as light and flexible as possible. HVLP on the other hand requires 5/16" air hose as the guns use a lot of air and small I.D. air hose can starve the gun of atomizing air. The 1/4” air hose can be used for short hose lengths of 15’ or less or for most conventional guns.

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Fluid Hoses- Low PressureFluid Hoses- Low Pressure

For low-pressure applications such as air spray or HVLP it is recommended that you use 1/4" nylon lined, low-pressure fluid hose for most coatings. Keep in mind that viscous materials such as adhesives may require 3/8" I.D. hose in order to maintain acceptable flow rates to the gun. For most adhesive applications, it is recommended that you use 3/8" I.D. fluid hose.

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Fluid Hoses- High PressureFluid Hoses- High Pressure

Do not use standard low-pressure fluid hose on Air-Assisted Airless pumps! The high pressures can blow low-pressure fluid hoses! Use only medium-pressure fluid hoses on these systems. The systems are supplied with 3/16" fluid hose with swivel connectors. 3/16” hoses use less coating to fill the hose, use less solvent to flush and generates less waste than 1/4" high pressure hose.

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Fluid Pressure Drop Fluid Pressure Drop Fluid pressure drop or loss should be considered when designing or purchasing a fluid supply system.

To maximize material savings and minimize waste stream generation in systems that will need to be flushed out frequently, it is recommended that manufacturers use the smallest diameter lines that will meet the needs of the application.

As viscosity greatly influences pressure loss, it should also be considered when sizing fluid lines.

Using too small of a line can result in insufficient fluid pressure (atomization) for higher pressure systems and insufficient flow rates for lower pressure systems.

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Fluid Pressure Drop Fluid Pressure Drop

Poise Zahn2 1/8” 3/16” 1/4” 3/8” 1/2”

0.3 20 33.55 6.63 2.10 0.41 0.13

0.5 24 55.91 11.04 3.49 0.69 0.22

0.7 30 78.27 15.46 4.89 0.97 0.31

1.0 41 111.82 22.09 6.99 1.38 0.44

Pressure Loss Per Foot In Relation to Viscosity In Poise

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Setting Up for Setting Up for SprayingSpraying

Insufficient air pressure and volume, as well as the contaminants in the compressed air such as oil and water affect many finishes. Guns that use high atomizing pressures such as conventional guns and guns that use high volumes of air are more susceptible to this than guns that use little or no atomizing air. We highly recommend that you always use clean, dry air.

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Checking the Air SupplyChecking the Air Supply

Oil & Water Extractors & Oil & Water Extractors & RegulatorsRegulators

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Air Pressure DropAir Pressure Drop

Air pressure and volume are directly related. If the volume of air required to operate an air motor or a spray gun exceeds that capacity of the compressor to supply that volume, than the air pressure will drop. This is critical when using HVLP guns as they are very dependent on volume or CFM. Items such as quick disconnects can severely reduce air volume and therefore air pressure.

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Setting the Fluid PressureSetting the Fluid Pressure

Fluid pressure, whether you are using a low pressure. medium pressure or high pressure system, is a critical element of setting up for spraying. In all systems fluid pressure is directly related to flow rate. The higher the fluid pressure the higher the flow rate. In medium and high pressure systems, fluid pressure is also the main source of atomization. Once you have established a value for your coatings fluid pressure, that value should be recorded for future reference.

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Fluid Flow RatesFluid Flow RatesFluid flow refers to the amount of coating emitted from the gun in ounces per minute (oz./min) or cubic centimeters (cc/min) . The fluid flow rate determines the of surface area or products that can be coated per minute.

Flow rates can be checked by triggering the spray gun into a beaker with atomizing air turned off for 1 minute, but the most accurate way is with a flow meter.

Flow rates from higher pressure guns can also be obtained in a similar manner but require the use of a small piece of high pressure hose.

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Verifying Flow Rates for Compliance Verifying Flow Rates for Compliance with Work Practice Standards (WPS)with Work Practice Standards (WPS)

As a manufacturer, what does flow rate mean to you?

At regulated facilities, the Work Practice Standard for each spray gun should state the flow rate at which it is to be used as part of the operator’s application procedure.

In order to verify compliance with the Work Practice Standards at regulated facilities, the inspector may know how to measure the flow rate of the different spray guns, as explained in the previous slide.

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Verifying Flow Rates for Compliance Verifying Flow Rates for Compliance with Work Practice Standards (WPS) with Work Practice Standards (WPS)

(continued) (continued)The flow rate should then be compared to the Work Practice Standard for that coating.

If the flow rate is out of the range stated in the WPS then the flow rate is out of compliance, which is a violation. Either the gun’s flow rate needs to be adjusted or the WPS for that gun needs to be revised.

A flow rate higher than the WPS also indicates that the finisher is emitting more paint and VOCs than may be necessary, leading to more pollution and air emissions (a P2 opportunity).

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Pump Stall and Pressure Pump Stall and Pressure CheckCheck

Before using a higher pressure system such as Air-Assisted Airless or Airless, where fluid pressure is critical for atomization, it is recommended that the pump be pressure checked and stall checked.

The easiest way to check pump pressure is to install a high pressure, liquid filled gauge on the fluid outlet of the pump or in or near the spray booth.

Operators can then easily verify that they are using the correct fluid pressure.

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Pump Stall and Pressure Pump Stall and Pressure CheckCheck

(continued)(continued)At a minimum, the pump should be primed and the pressure increased to slightly above the desired operating pressure.

Allow the system to sit idle for a few minutes.

The pump should not move.

Trigger the gun and stop the fluid piston on both the up and the down stroke.

If the pump won’t “stall”, maintenance is required.

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Setting & Checking the Setting & Checking the Atomizing Air PressureAtomizing Air Pressure

Once the flow rate has been established and set it is time to set the atomizing air pressure, if you are using an air atomizing gun or air air assisted gun. The atomizing air should always be set to the LOWEST possible value that gives you the atomization or finish quality you want at the speed that you want. Once you have determined this value it should be written down for future reference. When operating an HVLP gun it is necessary that you use the test gauge air cap in order to verify that you have set the air to 10 psi gauge or less, when the air is triggered.

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Setting the Atomizing Air-Setting the Atomizing Air-HVLPHVLP

When operating an HVLP gun it is necessary that you use the test gauge air cap in order to verify that you have set the air to 10 psi gauge or less, when the gun is triggered for air. Both the fan pattern air and the atomizing air must be at or below this value, not only to be compliant but to be efficient. The higher the air pressure on an HVLP gun, the lower the efficiency will be. As Air-Assist and Airmix® are already compliant, it is not necessary to have a test gauge air cap.

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Setting the PatternSetting the Pattern

Once you have established your flow rate and have set your atomizing air pressure, it is time to set your pattern width. The pattern should not be set more than a 1/2” beyond the part you are spraying. Ideally the pattern should be smaller than the part you are spraying. An excessively wide pattern increases the angle of deflection which reduces transfer efficiency. Any part of the pattern that misses the part is wasteful and costly. The pattern should be consistent with your productivity needs. Too small a pattern will require too many strokes.

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Checking the PatternChecking the Pattern

Once you have established your spray pattern, it is a good idea to check the pattern for defects such as uneven distribution of the paint particles or gaps or distortions in the pattern. A control sample of the pattern taken at a fixed distance from a test panel is the best way to confirm pattern integrity. To check distribution, turn the air cap or gun 90 degrees so that the pattern is horizontal. Trigger the gun in a stationary position and hold for a few seconds. The coating should run evenly from the entire width of the pattern.

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Curved Pattern

Plugged or damaged air passage in fan air jet. Possible bent nozzle.

Uneven Pattern

Plugged or damaged atomizing air passage. Fluid

needle in too far

Narrow Center Fat Center

Insufficient fluid Too much fluid pressure pressure Too much air Not enough air pressure pressure

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Checking the PatternChecking the Pattern

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Operator TechniqueOperator Technique

Once you have verified the integrity of your spray pattern, you are ready to begin spraying. It is crucial to your success that you use proper spraying techniques. There are several elements to good finishing technique, gun to part distance, gun to part orientation or targeting, gun angle, gun speed and triggering. The more consistent you become with these elements, the more consistent your results will be.

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Gun To Part DistanceGun To Part Distance

Gun to part distance is usually indicated in your spray gun’s manual or operating instructions. It is usually recommended that you maintain this distance from all of the substrates surfaces at all times, except when attacking difficult or complex shapes. However for the best results consistency is critical.

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6 Inches - HVLP 8 Inches - Air Spray 10 Inches – Air Assist 12 Inches - Airless

Technology

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Operator TechniqueOperator TechniqueGun orientation is the most common improper spraying technique and is often referred to as “gun waving”. This is directly attributed to a lack of training of inexperienced finishers although some finishers were taught this improper technique. Keeping the gun properly orientated keeps the fan pattern width consistent and the coating deposition uniform. When the orientation changes, the amount of coating applied to a specific area varies as the gun is actually closer to the part in the middle of the wave and further from the part at the ends of the wave.

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Gun To Part OrientationGun To Part Orientation

Improper Gun Orientation Proper Gun Orientation

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Keeping the gun properly orientated keeps the fan pattern width consistent and the deposition uniform. When the orientation changes, the amount of coating applied to a specific area varies as the gun is actually closer to the part in the middle of the wave and further from the part at the ends of the wave. This results in variations in mil thickness as well as finish quality as the coatings flow out at different rates based on the application amount. The wetter areas flow out better then the drier areas,


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Gun To Part AngleGun To Part Angle

The guns angle is easier to explain but harder to notice as the hand is not held in the line of sight of the eye. This technique is best observed by another person observing the operator and making adjustments verbally. There is however a new technology on the market that helps the operator see this for himself and make adjustments to his technique. The new laser guided technology allows operators to adjust to the proper gun distance, orientation and angle.

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Improper Gun to Part Angle Proper Gun to Part Angle

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Gun To Part AngleGun To Part Angle

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Gun SpeedGun SpeedGun speed is another technique for ensuring consistency. This is also referred to as rhythm. Like dancing or playing an instrument, this technique is harder to teach but if properly instructed most finishers can do it. The best way is to count but because of all the different substrates, the different geometry and complexities, it is not always practical to count.

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Gun TriggeringGun Triggering

Gun triggering is another common problem observed in finishing operations. The trigger should be pulled a fraction of a second before the part presents itself and end a fraction of a second after the gun passes the end of the part. Triggering too soon and letting the trigger go too late is inefficient, wasteful and costly. Over a period of hours, days and months, the cost of improper triggering can be thousands of dollars in extra coating usage and causes unnecessary VOC emissions.

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TargetingTargeting

Targeting or attacking the part plays an important role in obtaining an excellent finish. Finishers should be analytical in their approach to each item to be coated. It is recommended that manufacturers standardize how each part is attacked in order to gain consistent results. Difficult areas should always be coated first and then the easy areas. Parts should be approached from from to back and from the top to the bottom, keeping the overspray away from the freshly coated surfaces.

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Part PresentationPart Presentation

Whenever possible the part should be presented to the finisher in such a manner as to facilitate ease of application. Finishers who are forced to reach well beyond their comfort zone are at risk and finish quality will suffer. Whenever possible consider the use of step stools, ladders, man lifts, turntables and intelligent conveyance of the parts to be coated. The goal should be to allow the finisher to maintain proper gun to part relationships.

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Box Coat or Cross CoatBox Coat or Cross Coat

A technique used by some finishers is called box coating or cross coating. In this technique the gun moves horizontally across the part on the first series of passes and then moves vertically on the next series of passes. This helps ensure a uniform film build across the surface of the substrate. Your material supplier may actually require that you use this method to ensure finish quality or uniform coverage.

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OverlappingOverlappingThis technique usually requires a good eye. Good finishers do it well and the others don’t. In essence almost all spray gun and material suppliers agree that a 50% overlap is the norm. When overlapping the first stroke always starts with 50% of the pattern being over the part on the first stroke. On the second stroke the gun is dropped down so that the top of the pattern is now even with the top of the part. On the third stroke the gun is dropped down until the top of the pattern is now 50 % over the last stroke and 50% on the unfinished area directly below the last stroke.

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By properly overlapping the finish appearance becomes consistent and so does the film build on the surface of the part. Again the laser guided technology can help finishers by placing a laser beam directly at the 50% mark of the last stroke. After a while finishers develop an eye for this an can do it unassisted.

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OverlappingOverlapping

Checking The Checking The FinishFinish

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FilmFilm

For wood finishing, the film is a thin layer of a coating on a substrate. This coating can be measured wet with a mil thickness gauge or dry with a dry film gauge. For the most part we recommend using a mil thickness gauge by the finisher. After applying the coating, the wet mil gauge is pressed onto the substrate surface. Small hash marks will appear when the gauge is removed. The amount of coating applied is represented by the last hash mark between the ends of the gauge.

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Film Build & Mil ThicknessFilm Build & Mil Thickness

Usually coatings are applied in a series of passes over the part to gradually build up the film or mil thickness of the coating. Some technologies such as Air-Assisted Airless, Airmix® and Airless can lay down higher mils in a single pass or stroke. However even these technologies are often used when performing multiple passes or coats. During this process both the overlapping technique and the type of the spray pattern affect the ability to achieve uniform film build.

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Uniform Film BuildUniform Film Build

To achieve uniform film build several key elements must come together. The coating solids must be evenly distributed throughout the fluid in the system, the fluid delivery rate must remain constant, the atomizing air if any, must remain constant. Proper overlapping technique, gun to part distance and gun to part orientation, gun angle must be maintained. If using a system that utilizes fluid pressure as it’s main source of atomizing energy, the fluid pressure must also be consistent.

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Crosscut of Film BuildCrosscut of Film Build

1 Mil

1.3 Mils

Substrate

Different spray technologies can have dramatic results in uniform build

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Film Build Consistency Film Build Consistency Reduces VOCsReduces VOCs

Manufacturers will often apply more coating than necessary to ensure that the lowest measured mil thickness meets the specification for that application. In some cases, this can mean applying 30% to 50% more coating to the part then is necessary in order to compensate for the inadequacies of the application technology. In the previous slides the manufacturer in the first example had to apply 2 mils on average to ensure a minimum of 1 mil. In the second example, the manufacturer needed only to apply 1.3 mils to ensure a minimum of 1mil.

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Checking Mil ThicknessChecking Mil Thickness

Checking for consistent mil thickness of an applied coating helps maintain finish quality and increases transfer efficiency.This reduces VOCs by ensuring that the proper amount of coating is applied and thus reduces rework coating usage.

Every spray equipment operator should be equipped with a wet mil thickness gauge. It is an inexpensive tool and is simple to use.A manufacturer could realize a savings of 10 to 30% or more just from improvement in mil thickness monitoring.

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Wet Film Thickness GaugeWet Film Thickness Gauge

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Mil Thickness Gauge

1 2 3 4

Mil Thickness hash MarksMil Thickness hash Marks

1 2 3 4

In this example we can see that the teeth on the wet mil gauge has left four marks, the two on each end and the two between the ends. In this example the wet mils would be two.

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Checking Wet Mil ThicknessChecking Wet Mil Thickness

When checking pigmented or color coat mil thickness it is possible to look at the teeth of the gauge after you have pressed them into the coating. When you look at the teeth, the highest number tooth with the color coating on it is the mil thickness for that spot. It is important to take several readings to ensure mil thickness accuracy over the entire surface of the part or substrate.

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Checking The FinishChecking The Finish

After checking the mil thickness it is recommended that you inspect the substrate for any dry or light areas and if necessary, touch-up those areas before curing occurs. If the finish quality is below normal, you should recheck your process parameters backwards from the application of the coating back to the viscosity of the coating.

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Flushing & CleaningFlushing & Cleaning

Flushing & CleaningFlushing & CleaningAfter you have completed your finishing operation for the day, it is time to prepare the system for shut down. Much will depend on your process and your coating. For most systems, especially higher pressure systems, it is recommended that you leave the coating in the system, under pressure, except when using two or more component paint. Precautions must be taken so that the pump can not run should a fluid leak develop. This is easily accomplished by shutting off the air supply to the pump.

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Without air the pump can not run and therefore will not pump material if a leak does occur. Leaving material in the system under pressure, reduces waste generation and solvent use. VOC emissions are also reduced. As the higher pressure systems are more airtight than low pressure systems, such as pressure pots, the coating stays as fresh as it is in the container.

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The best system to reduce waste from flushing is a dedicated fluid system, one pump per primary color. The second best method is to use a color change system. The next best system would use an air/solvent purge device, then flushing with clean recycled solvent, new solvent then dirty solvent and the worst is flushing the existing color with the next color. It usually takes longer to flush out a coating or color with another and can lead to other finish contamination issues.

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Line & Gun CleaningLine & Gun Cleaning

When it is necessary to flush your system, NEVER spray the coating and solvent directly into the spray booth filters. It may be possible to reclaim some of the material in the hose and gun by either back flushing your Air Spray or HVLP pressure pot system or by pumping them dry with your pumping system.. NEVER back flush with any fluid pump.

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Line & Gun cleaningLine & Gun cleaning

After you have reclaimed as much coating as possible re-prime the pot or pump with solvent. Keep the atomizing air off. Trigger the gun with the fluid stream directed into a waste container until the solvent is clear and tacky free. For short time storage (overnight & weekends) it is O.K. to leave the solvent in the system. If storing for longer periods of time, it is recommended to use a slow solvent such as mineral spirits.

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Spray Gun CleaningSpray Gun Cleaning

Depending on your finishing process you may be required to clean your spray gun. Although the use of a gun washer is practical and efficient, many washers are incorrectly used and maintained. If you have a working gun washer use it, but remove the guns after cleaning and reinstall them on the system. Leaving the guns in a mixture of clean and dirty solvent is not recommended. Only the fluid head of the gun was designed for solvents, the other side is designed for air. Solvent can damage the o-rings and get deep into air passages.

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At a minimum, it is recommended that you wipe the gun off with a rag containing some solvent. Soak the air cap briefly in solvent, clean with a nylon bristle brush and then blow dry the air passages. Never use anything hard to clean out the air holes or jets of an air cap. This will affect the guns atomization characteristics. It is O.K. to soak fluid nozzles, needles and tips. Again, the best way is to soak briefly, brush clean, air dry and reinstall.

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Spray Gun CleaningSpray Gun Cleaning

Solvent Reclaim SystemsSolvent Reclaim Systems

Solvent recovery or reclaim systems can be an effective way to reduce operating costs by reusing old solvent. Dirty solvent is placed into the reclaim systems which heats the solvent to promote evaporation or distilling of the solvents. The solvents condense as they cool and are collected for reuse. The byproduct is a sludge, but the volume of waste is greatly reduced.

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Solvent RecorckeepingSolvent Recorckeeping

Depending on the regulations that apply to your facility, you may be required to keep track of the amount of solvent, the type of solvent, the amount evaporated into the atmosphere and the reason for the use of the solvent.

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Parts Washoff & Parts Washoff & RecordkeepingRecordkeeping

In the event that parts must be washed off you may be required to once again keep track of the type, quantities of solvent and reasons why the parts were washed off. Each part must be recorded and reported monthly.Washoff tanks must be normally closed when not in use. Rags used in this procedure should be deposited in a normally closed safety container.

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Fluid HandlingFluid Handling & Storage & Storage

Fluid Handling & StorageFluid Handling & Storage

The main environmental issue concerning fluid handling and storage is that containers must be “normally closed” when not in use.

A “normally closed container” means a container that is closed unless an operator is actively engaged in activities such as emptying or filling the container.

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There are other local, state and federal regulations that govern the handling and storage of flammable and hazardous materials. Agencies such as your local fire department, city or town ordinances and state and federal agencies such as OSHA and NFPA all have regulations and guidelines concerning these materials. It is your responsibility to be well informed and follow the regulations imposed by these agencies.

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Fluid Handling & StorageFluid Handling & Storage

Fluid HandlingFluid Handling

Care should be taken around all solvents and coatings. It is always recommended that you use gloves and protective clothing.

All fluid handling systems, including pressure pots and pumps, that contain flammable coatings or solvent should be grounded. Fluid moving through the system may create a static charge which could ignite the coating or solvent.

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It is always recommended that in areas where flammable liquids are being handled, be well ventilated. Coating and solvent fumes can collect and concentrate to explosive levels. Do not smoke or use any open flames when handling flammable materials.

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Fluid HandlingFluid Handling

StorageStorageAside from keeping all containers of coating and solvent in “normally closed” containers, there are several other ‘storage” issues we should mention. Again, local, state and federal agencies have regulations concerning the storage of flammable and hazardous materials. In general we recommend that you use safety storage cabinets and lockers. Never store coatings inside the booth. In some areas you can only have one day’s supply of coating near the booth. Large quantities may need to be in approved paint storage rooms or special buildings. Ventilation may be required as well as sprinkler systems, explosion proof lighting and blast doors.

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In general we recommend that you use safety storage cabinets and lockers. Never store coatings inside the booth. In some areas you can only have one day’s supply of coating near the booth. Large quantities may need to be in approved paint storage rooms or special buildings. Ventilation may be required as well as sprinkler systems, explosion proof lighting and blast doors.

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StorageStorage

Waste Disposal Waste Disposal

All coatings, including water based coatings contain solvents and other hazardous materials and should be disposed of in accordance with the regulations for your facility. Never pour coatings or solvents down the drain or onto the ground. Always use waste containers and recycle the waste or have it recycled for you by a certified waste disposal company. In most cases the coating and solvents you use remain your responsibility until they are recycled or incinerated.

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Equipment Equipment MaintenanceMaintenance

Equipment Preventative Equipment Preventative MaintenanceMaintenance

All parts that come in contact with dynamic fluids, such as paint, and gases, such as air, are subject to wear.

This includes cups, pots, pumps, hoses, fluid tubing, and of course, guns.

As spray guns are exposed to both coatings and air, they should be inspected at least once a month on a regular basis for fluid leaks and to ensure optimum performance.

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Equipment Preventative Equipment Preventative MaintenanceMaintenance

(continued)(continued)Replacing worn air caps, nozzles, and tips will help return the gun’s operation to its optimum performance and help ensure maximum transfer efficiency and finish quality.

The following slides show an example of how a worn spray tip leads to an inconsistent finish, low transfer efficiency, and increased VOC emissions.

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Gun Leak& Maintenance Gun Leak& Maintenance InspectionInspection

There are many different guns on the market. Some may have unique designs that may not fall within these guidelines, but for the most part the following are areas to look at for leaks on spray guns:

Almost all guns have a mechanical device that functions like a valve.

When opened the fluid can exit the gun.

When closed the fluid should remain in the gun.

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This valve is usually comprised of a spring loaded, trigger operated needle and a nozzle or a cartridge with a ball and a seat.

The area where the needle enters the fluid side or head of the gun is sealed with packings while the cartridge is sealed with an o-ring or gasket.

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Gun Leak Inspection & Gun Leak Inspection & MaintenanceMaintenance

Fluid Nozzle

Air Cap

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Packings

Fluid Inlet Fitting

EXEL-NA

Low Pressure

Packing

Packing Nut Fluid Needle

Spring Seal

Fluid Nozzle

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EXEL-NA

Fluid Adjustment Assy.

Packing & Nut

Fan Adj.

Air Cap Nozzle

Ring

Air InletTrigger

Gun Body

Air Valve

Fluid In

Low Pressure

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EXEL-NA

Medium Pressure

Air Cap Tip & Tip Seal

Seat Assembly Seat Seal Insert (seat) Seat Retainer

Cartridge Assembly Cartridge Seal & Needle

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EXEL-NA

Medium Pressure

Cartridge

Trigger Lock

Fan Adj.

Body

Air In

Inlet Fluid Filter

Trigger

Air Valve

Fluid Tube

Seat Assy..

Tip

Air Cap

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EXEL-NA

High Pressure

Cartridge

Seat

Reversible Tip

Tip Guard

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EXEL-NA

High Pressure

Filter

Handle

Trigger

Swivel

BodyCartridge

SeatTip Guard

Reversible Tip

Trigger Guard

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EXEL-NA

System Leak InspectionSystem Leak Inspection

Gun - Nozzle & Packing Fluid Inlet Fluid Hoses & Connections

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Fluid Outlet Cup Seal

Air Line

Air Regulator

Cup

EXEL-NA

Pressure Pot Leak InspectionPressure Pot Leak Inspection

Pressure Relief Valve

Head & Clamps

Fluid Outlet

Head Gasket

Fluid Tube

Shell

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Agitator Gasket

Regulators

EXEL-NA

Pump Leak Inspection & Pump Leak Inspection & MaintenanceMaintenance

All pumps have wearing hard and soft parts.

Hard parts such as cylinders and pistons wear slowly, while soft parts such as packings wear quickly.

The most common type of pump leak occurs on the upper packing* assembly.

Normally this problem can be fixed quickly by depressurizing the system and tightening the packing* nut or retainer.

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Normally this problem can be fixed quickly by depressurizing the system and tightening the packing* nut or retainer.

If tightening does not stop the leak, the packings* must be replaced.

*Tightening of packing glands is specifically included in § 129.103(c)(4)(i) as a repair for a leak.

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Pump Leak Inspection & Pump Leak Inspection & MaintenanceMaintenance

Upper Packing AssemblyUpper Packing Assembly

Lubricant Drain

Pump Body

Upper Gland Retainer

Upper Packing Glands

Lower Gland Retainer

Packing Nut or Lube Cup

Fluid Outlet

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Other Pump PartsOther Pump Parts

Piston

Upper Ball

Delivery Valve

Packing Washer

Packing Gland Retainer

Lower Packing Glands

Packing Gland Retainer

Upper Seat

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Other Pump Parts ContinuedOther Pump Parts Continued

Cylinder

O-Ring

O-Ring Ball Stop

Lower Ball

Foot Valve

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Finishing AccessoriesFinishing Accessories

There are many accessories available for coating application equipment that are designed to improve equipment performance, improve finish quality, minimize down time and rejects, and illustrate system operating parameters.

As they may be used in the handling or storage of coatings they may require separate leak inspection and maintenance plans.

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Spray Booth Spray Booth OperationOperation

Types of Spray BoothsTypes of Spray Booths

Dry Filter

Water Wash

Purpose of Spray BoothsPurpose of Spray Booths

The main purpose of a spray booth is to evacuate dangerous levels of hazardous vapors from the room in which the booth is located. Paint fumes can be deadly if not properly ventilated. Also paint fumes can be highly explosive and have been known to cause fires. The booth also removes toxic particulate matter, mostly paint particles, from the air surrounding the painting process.

Spray Booth filtersSpray Booth filters

Spray booth filters are designed to stop the particulate matter from escaping the building and being deposited into the atmosphere along with the VOCs.Most regulations in the country require that spray booth filters be at least 98% efficient in stopping the escape of particulate matter.The filters do not stop the VOCs, although some carbon absorption filters do stop some. Filters become clogged with use and prevent the booth from performing its function.

ManometersManometers

The purpose of the manometer is to indicate when the filters have become clogged sufficiently enough to warrant changing them. It is critical that manufacturers monitor the manometer for everyone’s safety. The manometer measure the difference in static pressure between the area in from of the filters and the area behind the filters. When the pressure differential exceeds the recommended value it is time to change the filters.

Spray Booth EnvironmentSpray Booth Environment

• Ensure adequate lighting

• Maintain clean finishing area

• Minimize exposure to contaminants

• Optimize air movement through booth

• Optimize booth temperature and humidity

• Optimize part location in booth

• Optimize part presentation to operator

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Typical Case Goods Spray Booth Typical Case Goods Spray Booth

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Better Booth for FinishingBetter Booth for Finishing

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Advantages of a Booth with Advantages of a Booth with Air Make-UpAir Make-Up

A closed booth with an air make-up system is the BEST booth design for minimizing rework and therefore emissions.

This type of booth provides its own clean and dry environment.

The positive air pressure created in the booth ensures that dust and dirt do not migrate into the booth and affect the finish quality.

The temperature is controlled, which also improves the finish quality. This in turn can mean less emissions from rework.

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Booth MaintenanceBooth Maintenance

Booth Cleaning

Booth Coat

Flame Retardant Paper

Lighting

Filters & Baffles

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Spray Booth CleaningSpray Booth Cleaning

Again, compounds containing more than 8% VOCs may not be used for cleaning off components of the spray booth unless it is being refurbished.

This does not apply to metal filters, conveyors, or continuous coaters and their enclosures.

If the spray booth is being refurbished, no more than 1 gallon of organic solvent may be used to prepare the booth for booth coating.

The booth coating shall contain no more than 0.8 lb VOC/lb solids, as applied. (§ 129.102, Table IV)

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Strippable Spray Booth Strippable Spray Booth CoatingsCoatings

Booth coatings help manufacturers maintain a cleaner finishing environment.

A dirty booth will affect finish quality which may result in rework.

To minimize this problem, manufacturers should use a peelable booth coating. These coatings are either clear or white.

The reflectivity of these coatings helps the operator to see the substrate better. When the overspray from the finishing process builds up on the booth coating, the booth coating should be peeled and a new coat applied.

The booth coating shall contain no more than 0.8 lb VOC/lb solids, as applied. (§ 129.102, Table IV)

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Flame Retardant PaperFlame Retardant Paper

Like booth coatings, flame retardant paper helps to keep the booth finishing environment clean.

A clean finishing environment reduces rework.

Reduced rework means reduced VOC emissions.

When the paper gets too dirty it should be replaced and disposed of properly.

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LightingLightingLighting in the booth affects coating usage and finish quality.

If the lighting is insufficient the operator may apply more coating then necessary, thereby emitting more VOCs.

Usually parts with cosmetic finishes are not reworked for excessive mils.

However some parts with protective finishes may have to be reworked to meet manufacturing specifications. If the operator applies too little coating, the part may be rejected by quality control, which may then require the part to be reworked.

Rework increases VOC emissions.

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Spray Booth FiltersSpray Booth Filters

Spray booth filters stop particulate matter, especially paint particles, from escaping into the atmosphere.

Lack of proper filter replacement procedures increases the potential for this matter to escape.

The uneven air movement through the booth caused by clogged filters affects transfer efficiency and finish quality, which may result in rework.

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BafflesBaffles

Baffles can be beneficial to some manufacturers by improving transfer efficiency and reducing VOC emissions for some finishing processes.

Baffles help to evenly distribute the air movement through the booth and around the part.

If the air movement around some areas of the part is faster than around other areas, transfer efficiency and finish quality may be negatively affected.

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BafflesBaffles(continued)(continued)

Baffles also help to distribute overspray more evenly over the booth filters.

In some applications, such as UV coatings, baffles are used to capture the overspray so that it can be recycled, thus decreasing coating usage and VOCs.

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There are MANY safety issues pertaining to finishing operations. There are local, state and federal agencies that have regulations concerning safety. OSHA is probably the most known and the most enforced agency concerning safety. Every manufacturer should be aware of the OSHA regulations concerning hazardous materials. NFPA is less well known, but is the agency that most local fire inspectors look to for guidance concerning fire hazards. There is a lot of overlapping of these two agencies concerning finishing.

Safety Issues

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Safety IssuesSafety Issues

It is not within the scope of this workshop to adequately cover these issues. The following is some common sense safety issues that at a minimum, should be considered:

Ventilation Respiration Fire extinguishing Protective

Clothing Gloves Safety Glasses Eye Wash Stations Grounding

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