Jan 31/11 51-23-00 Page 1 EFFECTIVITY: All z SD3-60 STRUCTURAL REPAIR MANUAL SRM 51-23-00 PAINTING OF AIRCRAFT AND COMPONENTS 1. Introduction This section outlines the various procedures and equipment used for the removal of paint, preparation, priming, painting, and the application of erosion resistant and heat resistant coatings on the SD360 aircraft. The information provided, will ensure compatibility with the original painting specifications, but should any further information be required then reference can be made to Shorts Process Specification (P.Spec 910, 911, 915, 916 & 918). 2. General A. Paint materials from different suppliers must not be mixed together, even though released to the same specification. B. In any paint scheme a primer coat is an essential feature. In addition to serving as an adhesive link between the underlying material and any top or finish coats it is chiefly responsible for the protective value of the finishing scheme. C. For aircraft interior surfaces sufficient protection is normally afforded by the primer only, but the exterior surfaces receive additional top or finish coats to provide the desired aesthetic effect and also to augment the protective value of the finishing scheme. Epoxy primers are compatible with polyurethane as well as epoxide based finishes. D. The primer coat should preferably follow immediately after the preparatory operations described in para 8. E. Similarly the finish coat should preferably follow immediately after priming, as this will reduce preparatory work. Surfaces which have been primed for longer than 48 hours may have deteriorated due to ageing, contamination or damage, and will require a refresher coat of primer in accordance with para 8. F. 3. Environmental Conditions Temperature and humidity in the Paint Shop must be continuously recorded, and be within the following range:- Temperature: 14 to 29°C Humidity: 35 to 80% The humidity in the area where paint is mixed must not fall below 35% or exceed 80%, and must be within ±5% of the level in the Paint shop. The temperature difference between the Paint Shop and the mixing area must not be greater than ±2°C.
Transcript
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SRM51-23-00 9.0.0.0PAINTING OF AIRCRAFT AND COMPONENTS
1. Introduction
This section outlines the various procedures and equipment used for the removal of paint, preparation, priming, painting, and the application of erosion resistant and heat resistant coatings on the SD360 aircraft. The information provided, will ensure compatibility with the original painting specifications, but should any further information be required then reference can be made to Shorts Process Specification (P.Spec 910, 911, 915, 916 & 918).
2. General
A. Paint materials from different suppliers must not be mixed together, even though released to the same specification.
B. In any paint scheme a primer coat is an essential feature. In addition to serving as an adhesive link between the underlying material and any top or finish coats it is chiefly responsible for the protective value of the finishing scheme.
C. For aircraft interior surfaces sufficient protection is normally afforded by the primer only, but the exterior surfaces receive additional top or finish coats to provide the desired aesthetic effect and also to augment the protective value of the finishing scheme. Epoxy primers are compatible with polyurethane as well as epoxide based finishes.
D. The primer coat should preferably follow immediately after the preparatory operations described in para 8.
E. Similarly the finish coat should preferably follow immediately after priming, as this will reduce preparatory work.
Surfaces which have been primed for longer than 48 hours may have deteriorated due to ageing, contamination or damage, and will require a refresher coat of primer in accordance with para 8. F.
3. Environmental Conditions
Temperature and humidity in the Paint Shop must be continuously recorded, and be within the following range:-
Temperature: 14 to 29°C
Humidity: 35 to 80%
The humidity in the area where paint is mixed must not fall below 35% or exceed 80%, and must be within ±5% of the level in the Paint shop.
The temperature difference between the Paint Shop and the mixing area must not be greater than ±2°C.
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4. Equipment and Materials
Other equipment and materials may be used in lieu of those listed below provided that their quality and performance is not inferior, and that they comply with the relevant specifications and have been approved by Bombardier Aerospace (Belfast) Quality and Materials Technology Departments.
A. Equipment for Paint Mixing
B. Equipment for Paint Spraying and Paint Film Measurement
C. Fillers and Stoppers
Stoppers and Surfacers
For approved Stoppers and Surfacers. Refer to Table 1.
D. Paint and Primer
For approved polyurethane finishes. Refer to Table 1.
For approved etch primers. Refer to Table 2
For approved epoxy primers. Refer to Table 3
Spatula, 100mm )
Commercially Available
Mechanically operated paint stirrer/mixer )100 mesh screen filter. PhospherBronze, Brass or Stainless Steel.(BS 410. APPENDIX C)
Durham, DL4 2QP, EnglandWhite Cleaning Cloths. General Purpose Commercially AvailableWet and Dry Abrasive Paper. 320 and 400 Grit Commercially AvailableScotchbrite sheet. Finishing Type �A� Very Fine 3M Co.TAK Rags TAK Chemicals Ltd
Pressure Sensitive Adhesive Paper Tape In 0.75, 1.0 and 1.5 Inch Widths
Commercially Available
Brown Kraft paper In 30 & 36 Inch widths Commercially AvailableCotton and Rubber Gloves Commercially AvailableDust Suit Commercially AvailableAirfed Protective Helmets Commercially AvailableRubber Covered Roller. 4 1/2 pound Commercially AvailableSolvent Safety Storage Can/Dispenser(Approved to Factory Inspectorate of Approval Certificate No.1)
Commercially Available
Pressure Sensitive Tape 1.0 inch wide. Code 250 3M Ltd.
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NOTE: Paints must be mixed in these ratios. It is not permitted to shorten cure by increasing the amount of activator of catalyst or by adding an accelerator.
Mixing of polyurethane finisher is to be carried out in a ventilated booth.
MANUFACTORER COMPONENTS APPROVAL PARTS BY VOLOME
VISCOSITY IN SECONDS (ES-B3)
POT LIFE @ 21°C
DRY FILM THICKNESS (MICRONS)
1700 South MtProspect Rd Box 5050Des PlainesI11. 60017
Base FE102 AFS 1605 2US Activator No 102 1 24-26 8 hours 40-50
Sikkens (UK)Akzo Coatings99 Station RoadDidcotEngland
Thinner C25/905 As requiredUK
APPROVED POLYURETHANE FINISHERSTable 1
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MANUFACTORER COMPONENTS APPROVAL PARTS BY VOLOME
VISCOSITY IN SECONDS 18-25°C BS-B3
POT LIFE @ 21°C
DRY FILM THICKNESS (MICRONS)
Base 9120P3000 DTD 5555 1PPG Industries (UK) Ltd Spray Reducer 1Rotten Park Street UK 2000 7 0004 27-32 8 hours 8-12Birmingham Thinner TDXL up to 10%England 2000 6 0020 up to 10%1700 South ML Base Chrometch Primer DTD 5555 1Prospect Rd Box 5050 US PR30B 1Des Plaines Thinners TH34B up to 10%Ill. 60017 Ordinary Thinners T22
orup to 10% 27 - 34 8 hours 4-8
Desoto Titanine Plc. Anti Chill Thinners T105 up to 10%Darlington Road UKShildonEnglandAkzo Coatings Inc.Aerospace Finishes US434 West Meats AveOrange CountyCalifornia 92065 Base HP143AS DTD 5555 1
Reducer 143R 1 27-32 8 hours 4-8Sikkens (UK) Thinner VTI/14 up to 10%Akzo Coatings UK99 Station RoadDidcotEngland
APPROVED ETCH PRIMERSTable 2
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NOTE: Paints must be mixed in these ratios. It is not permitted to shorten cure by increasing the amount of activator or catalyst or by adding an accelerator.
need for the addition of scotchweld 2216 a/b to be verified.
5. Health and Safety Precautions
A. Aircraft Safety
(1) The aircraft batteries are to be removed or disconnected.
(2) The aircraft shall be electrically grounded.
(3) Blank off all openings in area to be painted to prevent entry of sanding dust and paint spray ie static vents, etc.
(4) Mask off areas to protect from undesirable paint spray on working surfaces such as flap tracks, insulators, windows, de-icer boots, landing gear, etc.
(5) The sequence of operations for the movement of flaps and air-in-take deflectors shall be carried out after painting these systems or in those areas.
B. Paint Spraying Area and Personnel Safety
(1) No open flames or naked lights, are allowed in the painting area.
(2) The use of infra-red or other heat lamps in the painting area is prohibited.
(3) Smoking or eating is prohibited in the paint spraying area.
(4) Primers and paints shall be stored in accordance with the manufacturers instructions.
MATERIAL/SUPPLIER DESCRIPTION MIXING RATIO POT LIFE CURE TIME TIME BEFORE
ABRADING
Polystop LP (Sikkens) Stopper
Polyester Knifing
30 Parts Base 1 Part Hardener
7-15 minsat 25±3°C
30 minutesat 25±3°C
30-45 mins
KS 30 (Desoto Titanine)
Polyester Knifing Stopper
60 Parts Base 1 Part Hardener
7-15 minsat 25±3°C
30 minutes at 25±3°C
30-45 mins
Laminar X 500 Off-white surfacer (Dexter Corporation)
EpoxySurfacer
4 Parts Base 8-W-5. One Part Hardener 50-C-3. One Part Reducer (Brush Viscosity) or One or two parts Reducer (Spray Viscosity)
6 hours at 25±3°C
6 hoursat 25±3°C
6 hours
Approved Stoppers and SurfacersTable 4
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(5) Solvent contact with the skin must be avoided.
(6) Solvents must be kept in an approved Safety Storage Can/Dispenser.
(7) Cloths saturated with solvents must be disposed of in metal containers with close fitting lids. The containers must be emptied daily.
(8) Ensure correct safety equipment is used. Working overalls, Rubber Gloves and suitable Airfed Helmets should be used at all times during operations.
(9) Volatile liquids surfacers, and fillers, can be harmful by ingestion and by inhalation of their vapours, and the majority are also flammable. It is therefore essential that adequate ventilation is provided at all times, and that the necessary fire precautions are observed. Spray dust which has accumulated in ventilation ducts or spray booths must be removed by frequent cleaning.
(10) Ventilation ducts, filters etc., must be serviced regularly.
(11) All electrical equipment, switch gear and lighting must comply with BS 5345 (BASEFA Standard), or US Electrical Standard 00-25-172 (intrinsically safe electrical equipment).
6. Removal of paint
Partial or complete removal of paint from aluminium and composite surfaces. Refer to 51-22-00, pb1.
7. Repainting of Aircraft
The two systems employed by Bombardier Aerospace (Belfast) for aircraft repainting are:-
NOTE: System 2 incurs an additional weight penalty to the aircraft.
A. System 1 is the most demanding and time consuming method of paint removal. It is however the only method approved by Bombardier Aerospace (Belfast) to completely remove paint. Operators may find that chemically stripping an aircraft to bare metal is a difficult and hazardous operation, but may be necessary for inspection for corrosion, surface or structural damage. It should be noted that on some areas of the aircraft, ie wing and fuselage areas, an adhesive primer eg BSL 101 (red colour) is applied during bonding manufacture. Adhesive primers are almost impossible to remove, and should if possible be left intact as they will provide an excellent surface for subsequent repainting.
System 1 - Refer to 51-22-00, pb1. Overall chemical stripping (in accordance with back to bare metal, followed by the application of a chemical conversion coating, epoxy priming and topcoating.
System 2 - Mechanically abrading and partial stripping, (where necessary), followed repainting over the existing scheme.
After paint stripping the following procedures should be applied:-
(1) Treat any bare metal surfaces in accordance with paragrapgh 8. K.
(2) Epoxy prime overall in accordance with paragraph 9.A. through 9.E.
(3) Finish topcoat as required in accordance with paragraph 9. F.
B. System 2 is employed where a change of livery is required, and where inspection for corrosion, surface or structural damage is not necessary or the time, facilities and expense prohibit the use of System 1.
The success of this system depends on the extent of the abrading and repainting, which in turn will be influenced by the existing colours on the aircraft.
If the aircraft is mainly white, with a minimum of colour, cheat lines and logo, the repaint will be relatively straightforward. However, difficulty may be experienced in covering dark colours successfully. In such cases local chemical stripping is advised.
If the existing livery is predominantly coloured, it will require overall abrading, and the following procedures should then be applied:-
(1) Abrade in accordance with paragraph 8. E.
(2) Primer paint (as required) in accordance with paragraph 9. A. through 9. E.
(3) Finish coat as necessary in accordance with paragraph 9 (6).
NOTE: When repainting the flying control surface, if the existing paint system has not been abraded prior to repainting (as noted above at para 7.B. (Refer to (1))), then the additional weight penalty incurred may be sufficient to disrupt the balance condition. In such circumstances rebalancing will be necessary.
8. Surface Preparation for Metallic & Composite Components
A. General
All areas not requiring priming/or painting shall be protected as follows:-
(1) Construct, using Brown Kraft Paper, a mask of the required shape and size.
(2) Secure mask over the specified area with Pressure Sensitive Adhesive Paper Tape.
(3) For small areas, masking tape only may be used.
B. Paint Stripping
Refer to 51-22-00, pb1.
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C. De-nibbing
Use clean Brown Kraft Paper as a mild abrasive to remove minor surface irregularities.
D. Solvent Cleaning
Wipe areas as required with clean white cloths dampened with MEK, or acetone cleaning fluid, exposing fresh cloth surfaces as necessary, until all contamination has been removed. Always add solvent to cloth. Do not dip cloth into fluid. Do not allow the fluid to evaporate to dryness on the surface, but dry by wiping with clean white cloths. Do not dampen cloth directly from the main cleaning fluid container. Use only an approved Safety Storage Can/Dispenser correctly labelled with fluid type. After use discard the used cloths in a metal safety bin.
After solvent cleaning parts must not be handled with bare hands. Wear clean white cotton gloves.
E. Abrading
Dry abrade using 320 or 400 grit abrasive paper. Remove sanding residue by wiping with clean TAK rags. If smoothing filler use either water or a cleaning fluid to lubricate the action of the abrasive paper so as to produce a smooth, level, fine grained surface. Remove all traces of abrasive and sludge, particularly from crevices. If water or solvent is used allow at least one hour drying time before subsequent operations.
NOTE: If abrading composite surfaces take care not to expose the composite fibres.
Wet abrasion is not permitted on primed parts, unless the epoxy primer has been applied for more than 7 days.
F. Refresher Priming
Whenever a primer surface has agred or become contaminated it is necessary to return it to a suitable condition for subsequent finish coating. If only slight deterioration has taken place solvent cleaning, with or without mild abrasion, may suffice to reactivate the surface. In more severe cases, however, it is additionally necessary to apply a very light coat of epoxy primer. This 'refreshes' the surface and provides a good ground for subsequent paint. The primer is prepared in the normal manner, (Para 9.C), and applied as lightly as possible consistent with surface wetting.
H. Primed Surfaces more than 48 hours old and/or contaminated
(1) Mask as required. (para 8.A.)
(2) Lightly Abrade. (para 8.E.)
(3) Solvent Clean. (para 8.D. )
(4) Apply a refresher coat of primer (para 8 F.) and allow to dry for 4 hours minimum.
(5) Solvent Clean. (para 8.D.)
(6) Apply Finish Coating. (para 9.F.)
I. Filled and Flatted Surfaces either more than 48 hours old and/or contaminated.
(1) Mask as required. (para 8.A.)
(2) Lightly Abrade. (para 8.E.)
(3) Solvent Clean. (para 8.D.)
(4) Apply Finish Coating. (para 9.F.)
J. Finished Surfaces requiring additional Coating or the addition of Markings and Placards
(1) Mask as required. (para 8.A.)
(2) Lightly Abrade. (para 8.E.) if more than 200 hours old.
(3) Solvent Clean. (para 8.D.)
(4) Apply additional Finish Coat or Marking and Placards as required. (para 9.F.)
K. Metallic Components
Bare aluminium surfaces especially those exposed following chemical stripping of/or mechanical abrading can be suitably treated using the Alodine/Alocrom 1200 chemical conversion coating. Refer to 51-24-00, pb1.
Parts which require the Alodine/Alocrom treatment followed by epoxy priming can be categorised as follows:-
(1) Parts ultimately forming part of the outside profile of the aircraft.
(2) Parts which do not form part of the outside profile, but could be painted within 16 hours of Alodine/Alocrom treatment.
(3) Parts which because of time consuming operations subsequent to anodising cannot be painted within 16 hours of anodising.
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Parts in category (a) must be painted in accordance with paragraphs 9.E. and 9.F. should 16 hours elapse before painting, the parts must be stripped, re-alodined/alocromed and painted within the next 16 hour period. Refer to 51-22-00, pb1. Etch primer must not be used.
Parts in category (b) may of course be painted within 16 hours of anodising. Should 16 hours be exceeded the parts must be etched before epoxy priming.
Parts in category (c) are to be etch and epoxy primed in accordance with Paragraphs 9.A. through 9.E.
L. Composite Components
(1) General
Laminate and honeycomb composite surfaces require careful preparation prior to priming so that the required standard and appearance is achieved when final top coating is carried out.
The composite surfaces prepared in accordance with this section, include exterior, interior, structural and non-structural components, prior to the application of epoxy primer in accordance with paragraph Refer to 9..
The stopper and surfacer materials shall be usable for a period of 6 months from the date of receipt when stored at a temperature of 20 ± 2°C. Materials which have exceeded the above storage time may be re-lifed at the discretion of the local controlling laboratory.
(2) Procedures
(a) Operational Sequence
Refer to Figure 1.
The following procedures must be applied in continuous sequence. No single operation may be omitted.
Lightly dry abrade the surface of the composite component using 320 or 400 grit abrasive paper, taking care not to expose the composite fibres.
(c) Solvent Cleaning
Wipe areas as required with clean white cloths dampened with cleaning fluid, exposing fresh cloth surfaces as necessary, until all contamination has been removed. Always add solvent to cloth. Do not dip cloth into fluid. Do not allow the fluid to evaporate to dryness on the surface, but dry by wiping with clean white cloths. Do not dampen cloth directly from the main cleaning fluid container. Use only an approved Safety Storage Can/Dispenser correctly labelled with fluid type. After use discard the used cloths in a metal safety bin.
After solvent cleaning parts must not be handled with bare hands. Wear clean white cotton gloves.
(3) Pinhole Filling
Do not use pinhole filler as a smoothing agent. A continuous layer is detrimental to subsequent primer adhesion.
(a) Stir the filler to a uniform consistency
(b) Prepare the surface to be filled in accordance with Paragraphs 8 L (2) (a), and (c).
(c) Apply the filler to the cleaned surface using hand pressure to force the material into any pinholes.
(d) Allow to dry until conditioner turns white. (Approximately 30 minutes at 21 to 32°C).
(e) Thoroughly wipe off excess material with a clean white dry cloth. Scotchbrite Sheet, Finishing, Type A may also be used. Do not use water or cleaning fluid as they would remove the static conditioner on contact.
(f) Determine if surface filling is required. If necessary apply the filler, in accordance with the appropriate part of Paragraph 8.L. (4) (b) within 24 hours.
(4) Surface Filling
Refer to Table 4.
Small irregularities, indentations, etc., other than pinholes, must be filled with an approved stopper as listed, and in accordance with the following procedures.
NOTE: Use only Static Conditioner Filler 28-C-1 for pinhole filling. (See Paragraph (3)).
Refer to Table 4. Mix stopper components in the ratios specified, and label the container immediately after mixing with the date and time of mixing and the pot life expiry time.
NOTE: Material which has exceeded its pot life must be discarded.
Apply by filling the surface irregularities with the mixed filler and smooth with a spatula, using firm hand pressure.
Refer to Table 4. Allow to cure.
Abrade to original profile, (paragraph (2) (b)) taking care to observe the time before abrading. Refer to Table 4..
Remove sanding residue by wiping with clean TAK rags.
(b) Laminar X 500 Off-White Surfacer
When Laminar X 500 is specified by the Engineering Drawing it may be applied by burhsing or spraying.
The procedures are as follows:-
u. Mix the surfacer components in the ratios specified and add reducer as requried to give a brush or spray viscosity.
Apply a single brush coat, or apply a single cross coat using a paint spray gun.
NOTE: If further coats are necessary, allow to dry for 10 minuts at 18 to 25°C between each coat.
Allow to cure. Refer to Table 4.
Lightly abrade, if required, to original profile (Paragraph (2) (b)) taking care to observe the time before abrading. Refer to Table 4..
Remove sanding residue by wiping with clean TAK rags.
(5) Quality Requirements
The Quality Department shall be satisfied that the requirement of this section have been complied with, and that prior to priming, the surfaces of the components and assemblies are smooth and free from defects, such as dents, cracks, and other surface irregularities.
9. Application of Primers and Polyurethane Finish Coating
A. The following priming and painting procedures are to be applied in a continuous sequence. No single operation should be omitted.
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B. Preparation
The primer should be prepared 30 minutes before use. it must be discarded 8 hours after mixing.
The polyurethane paint must be used within the potlife stated. Refer to Table 1.
Before opening the containers
(1) Check identities of contents.
(2) Shake, up-end etc., for several minutes to mix contents.
(3) Wipe dust etc., from containers.
(4) Open containers and stir contents, using a hand held stirrer until each component appears homogeneous. Use a separate stirrer for each primer component.
C. Mixing
(1) Mixing or paint and primer is to be carried out in adequately ventilated areas.
(2) Mix paint and primer components in the ratios specified:
- Polyurethane Finishes. Refer to Table 1- Approved Etch Primers. Refer to Table 2- Approved Epoxy Primers. Refer to Table 3.
(3) Mix thoroughly for 1 to 3 minutes using a mechanical stirrer, or for 4 to 6 minutes if mixing by hand.
(4) Determine the viscosity as specified:
- Polyurethane Finishes. Refer to Table 1- Approved Etch Primers. Refer to Table 2- Approved Epoxy Primers. Refer to Table 3.
(5) If necessary adjust mixture with the appropriate thinners to obtain the required viscosity.
(6) After mixing has been completed the primer must be passed through a 100 mesh screen filter into a clean container.
(7) Allow mixed primer to stand for 30 minutes in the Paint Shop environment prior to use.
D. Application of Etch Primer
(1) Use paint spraying equipment (para 4.B) ensuring that correct working pressures are employed.
NOTE: For suction type equipment 40 psi is required at the gun.
(2) Apply one light coat of etch primer, which, when dry, shall be within the thickness limits stated. Refer to Table 2
(3) Record the date and time of application.
(4) Allow to air dry for not less than 2 hours and not more than 8 hours before application of epoxy primer.
(5) Examine for appearance and check for adhesion. (para 11).
E. Application of Epoxy Primer
(1) Use paint spraying equipment (para 4.B.) ensuring that correct working pressures are employed.
NOTE: For suction type equipment 40 psi is required at the gun.
(2) Apply one double track coat of epoxy primer, which, when dry, shall be within the limits stated. Refer to Table 2
(3) Record the date and time of application.
(4) Air dry for not less than 4 hours and not more than 24 hours prior to application of finish coat.
(5) Examine for appearance and check for adhesion. (paragraph 11).
NOTE: The final coat of epoxy primer must not be wet abraded prior to the application of polyurethane finish.
F. Application of Polyurethane Finish
Allow at least 24 hours for the aircraft structure temperature to reach that of the surroundings in the paint shop before painting. During this period the aircraft surface can be prepared for priming.
NOTE: (a) The environmental conditions quoted in para 3. and 5. must be observed.
(b) To remove dust etc., periodically wipe the surface being painted with a TAK rag. Use only new TAK rags immediately prior to finish coating.
(1) Use paint spraying equipment para 4.B ensuring that correct working pressures are employed.
NOTE: For suction type equipment 40 psi is required at the gun.
(2) For all finishes, except FE 115, apply one light coat, allow to dry for 30 to 60 minutes, and then apply a wet double track coat which, when dry, shall be within the limits stated. Refer to Table 1.
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(3) To obtain the required ry film thickness for FE 115 erosion resistant paint, proceed as follows:-
Apply two wet on wet double track coats, and allow to dry for 1 to 3 hours. Repeat this procedure 3 or 4 times to give a dry film thickness as specified. Refer to Table 1.
(4) Record the date and time of application of each colour.
(5) Allow to air dry for 16 hours minimum prior to taping, masking and application of overcoat or markings if required.
(6) Following final painting of aircraft allow 3 days minimum before outside exposure and 7 days minimum before flight.
NOTE: If an aircraft is subjected to rain within 7 days of painting it must be dried off as soon as possible.
(7) Examine for appearance and check for adhesion. (para 11).
During final painting of aircraft, matt down composite components, (previously prepared in accordance with paragraph 8 (L) and apply a light coat of epoxy primer. Dry as per paragraph 9 (5) (d) and apply finish coating.
10. Repairs to Damaged Finish Coatings
A. Damage Slight - Finish Coat only affected
(1) Lightly Abrade. (para 8. E.)
(2) Solvent Clean (para 8. D.)
(3) Apply Finish Coating. (para 9. F.)
B. Damage Moderate - Finish and Primer Coat affected
(1) Lightly Abrade (para 8. E.) to expose primer layer.
(2) Solvent Clean. (para 8. D.)
(3) Apply refresher coat of primer. (para 8.F.)
(4) Apply Finish Coating. (para 9.F.)
C. Damage Severe - Penetration to Substrate Surface
(1) Strip Paint.
(2) Brush ALODINE/ALOCROM 1200 on Aluminium Alloy components. Refer to 51-24-00, pb1.
11. Inspection for Appearance, Ahesion and Thickness
A. Appearance
Primed and/or painted areas are to be uniform in colour and texture. Swelling, wrinkling, 'orange peel' effect, spray dust, roughness, sags, or runs are absent. The primer and/or paint are to be free from entrapped particles and show no evidence of 'blushing'.
B. Adhesion Test
No adhesive failure is to take place when tested as follows:
(1) Primer
Firmly press 6 inches of 1.0 inch wide Pressure Sensitive Tape, Code 250, on to a selected area. Age of tape not to exceed six months. Remove the tape with a single, firm, abrupt perpendicular motion. Examine the tape and the bared area for evidence of primer adhesion failure.
(2) Finish Paint
Adhesion tests shall be made on the completed exterior finish of the painted area after drying for a period preferably of at least 48 hours on a sufficient number of selected areas to assure that a satisfactory level of adhesion has been maintained overall.
Tape a piece of cloth to the area under inspection. The test area shall be kept soaked for 24 hours minimum wiht tap or distilled water. The test area shall have a minimum area of three inches.
Remove the wet cloth and blot up the surface water. Immediately apply a one inch strip of Pressure Sensitive Tape, Code 250, adhesive side down. Age of tape not to exceed six months. press the tape down, using two passes of a 4-1/2 pound rubber covered roller or employ firm pressure with the hand.
Remove the tape in one abrupt motion and examine the tested area for any paint damage such as removal of paint at one of the layers of the finish system, or removal of the entire system from the painted surface.
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C. Thickness
When measured with a suitable instrument, eg a PERMASCOPE, the polyurethane finish thickness shall be within the limits stated.
- Polyurethane Finishes. Refer to Table 1- Approved Etch Primers. Refer to Table 2- Approved Epoxy Primers. Refer to Table 3.
NOTE: (1) The accuracy of the PERMASCOPE must be checked at six monthly intervals.
(2) When calculating the finish coating thickness, allowance should be made for the etch primer (if applicable) and the epoxy primer thickness.
12. Application for Erosion Resistant Coatings
A. General
- Refer to Figure 1.- Refer to Figure 2.
Erosion resistant paint is applied together with, or over, the deocrative paint scheme, to reduce erosion damage in the impingement areas of the aircraft. See Figs Refer to Figure 1 & Refer to Figure 2, for specific areas of erosion coating.
B. Preparation
(1) For areas primed ready for painting, in accordance with Paragraphs 9. A. to 9. E., the erosion resistant paint is to be applied as soon as possible after the minimum drying time specified in Table Refer to Table 3.
(2) For aircraft already painted with polyurethane finish coat, the area to be covered must first be solvent wiped in accordance with Paragraph 8.D. Dry abrade the surface using 320 or 400 Grade abrasive paper. Remove sanding residues by wiping with clean TAK rags. Apply refresher coat of primer in accordance with Paragraph 8.F.
C. Application
- Refer to Figure 1.- Refer to Figure 2.
Erosion paint (FE 115) to be applied as 3 overlapping coats to dimensions shown (sections aa, bb, cc or dd) in accordance with paragraph 9.F. Refer to Table 1.
