Wood Finishing

By: Ryan Hawthorne, Jonathan Kavanagh,Sean Redmond, Ed Darrh

Finishing Safety

When in lab, wear your safety glasses. Wear Proper clothing. Wash hands immediately after use of any finish. Keep solvents away from heat. Use in a ventilated room. After using any finish, close all containers and put

away properly. Clean up any spills that may be a hazard in the lab.

Finishing Wood

The two main reasons for finishing wood include: To protect it To add to it's beauty

* When finishing, take your time, DON’T RUSH!

Three Types of Wood Finishes

Transparent Coatings- coatings that can be seen through. Ex. Shellac, varnish, lacquer

Penetrating Finishes- these soak into the wood rather than just coat it. Ex. Linseed Oil, Danish Oil

Opaque Finishes- covers the surface completely, cannot be seen through. Ex. Paint, enamel

Transparent Coatings

Varnish- a preparation consisting of various resins, dissolved in an oil or in alcohol. When applied to the surface

of wood, it dries and leaves a hard, glossy transparent coating. Shellac- a varnish made by dissolving this material in

alcohol or a similar solvent.

Lacquer- a protective coating consisting of a resin, sometimes with pigment added.

Resin – Resin is a thick and sticky yellowish- brown substance used to chemically bond materials together.

Penetrating Finishes

Linseed Oil- A yellowish oil extracted from the seeds of flax and used as a drying oil in paints and varnishes and in linoleum, printing inks, and synthetic resins.

Danish Oil- is a blend of oils and resins that penetrates, seals, and preserves wood surfaces.

Finishing Supplies

Abrasives Brushes Solvents Wax Oils Paints

Brushes used for Finishing

Two main brushes used are bristle brushes and foam polybrushes. Natural bristle brushes- are made with hog hair, commonly

used with oil base paints. Synthetic bristle brushes- are made of nylon or polyester,

commonly used with water soluble finishes, and most oil base finishes. Foam polybrushes- made of plastic foam tapered on both

sides to a sharp point, can be used on most finishes.

Finishing Considerations

Project design Type of wood being used Projects intended use What do you want your end result to look like? Will it be exposed to heat, or moisture?

Preparing the Surface

After assembling the project, check for the following before applying your finish:

Dried glue Dents Chips Scratches

Preparing Surface Cont…

Remove access glue Remove Mill Marks Correct dents, chips or gouges; Using hot steam, Wood fillers may be needed, such as a wood

patch. Fill deep cracks and gouges with wood filler or water putty; leave the filler slightly high to allow for shrinkage as it dries. When the patch is dry, sand it smooth.

Sanding

Sanding is crucial to preparing your wood for a finish, whether it be hand or power sanding.

Anyone tell me why? Different grit sand paper

Coarse- (80 grit) Medium to fine- (100-180 grit) Very Fine- (220-280 grit)

Applying Stains and Clear Finishes

Staining- is the process to change the color of the wood without changing it’s texture.

Types of stains: Pigment stains -are made by adding color pigments together.

Ex. Mineral spirits, etc

Penetrating stains – are made by mixing aniline dyes in oil. Ex. Minwax, etc

Applying Stains Cont…

Wood Stain Finishes: Wood Toned - Lightly pigmented wood-toned finishes add

color to the wood, while enhancing its natural beauty. Semi-Transparent- Semi-transparent finishes allow both the

natural grain and texture to show through.

Solid Color- The most durable finish, solid color stains reveal

the texture of the wood, but generally conceal the grain.

Clear Finishes

Two basic types of clear top-coat finishes:

Those that penetrate the wood Ex- linseed oil, danish oil

Those that stay on top of the surface Ex. Shellac, varnish, polyurethane and lacquer

Spray Finish

Applying Sealer

After stain has dried completely, a sealer should be applied over the stain before a clear finish is applied. Why?

-This prevents the stain from bleeding into the clear coat which causes the end result to be cloudy.

Applying a filler

This is put on over the sealer to seal the pores of the wood before applying a clear finish.

Apply filler first along the grain of the wood. Then work across the grain to fill the pores completely.

Applying Paint and Enamel

These may include, water based latex or oil based.

An enamel paint is a paint that dries to an especially hard, usually glossy, finish.

Before applying paints, a primer should be applied, priming ensures better adhesion of paint to the surface, increases paint durability, and provides additional protection for the material being painted.

Applying paint and enamel cont…

Generally two coats of paint or enamel are applied.

Between each coat, a light sanding job will help with the looks of your finish.

Wood Finishing Review

Keep in mind, all safety precautions when working in the lab.

Two main reasons to finish your wood; To protect it To add to its beauty

There are many various finishes, your choice depends on many factors such as;

Type of wood used Project design Projects intended use Visual appearance Will it be exposed to heat or moisture?

Wood Finishing Review Cont…

Before applying your finish make sure you prepare the surfaces being finished. This includes;

Check for imperfections Correct those imperfections Apply finish

• Take your time, don’t Rush!!!

Any Questions???

Support Resources

http://home.howstuffworks.com/guide-to-furniture-finishes-ga4.htm

http://www.diynetwork.com/how-to/natural-wood-finishes/index.html

http://home.howstuffworks.com/guide-to-furniture-finishes-ga5.htm

http://home.howstuffworks.com/guide-to-furniture-finishes-ga2.htm