ACM-125 AIRCRAFT PAINTING Flashcards
(252 cards)
1
Q
What is the focus of Chapter 5?
A
Fabric covering
2
Q
What is the main topic of the section following Chapter 5?
A
Finishing process for fabric materials
3
Q
Why should technicians be aware of finishing systems for fabric-covered aircraft?
A
Because fabric-covered aircraft require refinishing
4
Q
What materials are used to protect fabric in aircraft covering?
A
Layers of dope containing fungicide and aluminum paste
5
Q
What are the aesthetic properties of finishing systems focused on?
A
Pleasing and durable finish
6
Q
What is a drawback of the traditional dope finish?
A
Prone to cracking
7
Q
What finishing systems are now available for fabric-covered aircraft?
A
Wide selection beyond nitrate or butyrate dope
8
Q
What do some STC systems require regarding topcoats?
A
Use of compatible paint or finishing products
9
Q
What is necessary for the finish to withstand continuous flexing?
A
The finish must be flexible
10
Q
What materials are used as plasticizers in dope films?
A
- Castor oil
- Tricresyl phosphate
- Modern vinyl resins
11
Q
What happens to plasticizers over time?
A
They migrate out of the dope film, causing brittleness
12
Q
What type of damage can occur to the dope film?
A
Cracking, usually in a ringworm form
13
Q
What environmental factors can cause premature loss of strength in fabric?
A
- Sunlight
- Moisture
14
Q
What is the first step in rejuvenating a brittle dope film?
A
Scrub the old finish with Scotch-Brite pads and water
15
Q
What should be used to remove wax from the surface before rejuvenation?
A
A rag dampened with an appropriate solvent
16
Q
What is rejuvenator primarily made of?
A
Potent solvents and plasticizers
17
Q
What does the first coat of rejuvenator do to the fabric?
A
Loosens the fabric
18
Q
What is the purpose of applying a second coat of rejuvenator?
A
Pulls the fabric back taut
19
Q
What should be done after sanding the surface during rejuvenation?
A
Wash off the sanding residue
20
Q
What type of dope should be applied after rejuvenation?
A
Aluminum pigmented butyrate dope
21
Q
How should the finish coats of dope be applied?
A
As heavily as possible without running or sagging
22
Q
What should be done if lighter coats are necessary?
A
Apply several top coats to fill the weave of the fabric
23
Q
What type of spray equipment allows more dope to be applied with less thinner?
A
Pressure pot
24
Q
What is the recommended mixture for achieving a glossier finish with pigmented dope?
A
Mix about 20% clear dope with the final coat of pigmented dope
Using more than 20% clear dope can lead to degradation from UV rays.
25
What is the purpose of adding Ultra Violet blocker to topcoats of paint?
To prevent UV damage to the finish
## Footnote
Chemical blockers are less effective than aluminum dope coats.
26
What should be done to achieve a deep gloss finish when applying pigmented dope?
Spray on several very thin coats and wet-sand with 600-grit sandpaper between each coat
## Footnote
Hand-rubbing with rubbing compound and wax is recommended after drying.
27
What factors can complicate the application of dope and fabric finishing?
Changing humidity and temperature conditions
## Footnote
These factors can affect equipment settings and chemical makeup.
28
What is essential for good dope adhesion?
Proper surface preparation
## Footnote
All paint or enamel must be removed before applying dope.
29
What can happen if nitrate dope is sprayed over butyrate dope?
The topcoat may peel off in strips
## Footnote
This occurs because solvents in nitrate dope cannot penetrate the butyrate film.
30
What issue arises from using too much aluminum powder in aluminum dope coats?
Topcoats may peel off
## Footnote
A thin layer of aluminum dope is recommended to avoid degradation.
31
What is blushing in dope finishing?
Blushing occurs when high humidity causes water to condense in the dope film, leading to a porous and chalky appearance
## Footnote
Blushed finishes are not as strong as normal finishes.
32
How can blushing be prevented during dope application?
By using retarder in the dope to slow evaporation or by warming the air to lower humidity
## Footnote
Waiting for more favorable conditions can also help.
33
What should be done if the dope has blushed and the conditions are not too severe?
Spray a mixture of one part retarder and two parts thinner in a light mist coat
## Footnote
This helps to melt the blushed surface film.
34
What causes pinholes in dope finishing?
Excess heat or wind causing the surface to harden, trapping vapors that form bubbles
## Footnote
Bubbles that burst leave pinholes in the surface.
35
Fill in the blank: The most common trouble with dope finishing is _______.
blushing
36
__________ are used in aircraft dope to make its film flexible
[plasticizers]
## Footnote
Plasticizers are substances added to materials to increase their flexibility and workability, commonly used in various applications including paints and coatings.
37
6-5
A dope film should be scrubbed with _____________ and water and any wax removed with an appropriate solvent before the rejuvenator is sprayed on.
Scotch-Brite
38
6-5
Rejuvenator is a mixture of potent _________ and ________.
solvents
plasticizers
39
6-5
Rejuvenators restore the __________ to a dried-out dope film
plasticizers
40
6-5
Finish coats of dope should be sprayed on with a _________ (heavy or light) coat.
heavy
41
6-5
Colored dope may be given a glossier finish by mixing it with up to __________ % clear dope.
20
42
6-5
The topcoats of a doped finish may peel off if there is ________ (too much or too little) aluminum powder in the aluminum dope coats.
too much
43
6-5
A dope film blushes when _________ condenses out of the air into the freshly applied dope film.
moisture
44
6-5
Mixing __________ with the dope will prevent blushing if the conditions are not too severe.
retarder
45
6-5
The relative humidity of the air may be lowered to prevent blushing by __________ (warming or cooling) the air.
warming
46
6-5
Two causes for pinholes in a dope film are:
1. Excessive heat or wind.
2. Excessively atomized spray gun air
47
6-5
Three causes for runs and sags in a dope surface are:
1. Moving the gun too slowly
2. Holding the work too close
3. Not thinking the dope properly
48
6-5
Orange peel in a dope surface may be caused by:
1. Improper spraying techniques
2. Thinners evaporating too quickly
3. Air drafts over the surface
49
6-5
Localized spots within the dope film that do not dry are called:
fisheyes
50
6-5
Dope that is brushed on too heavy or brushed when it is too cold will cause dope __________ .
roping
51
6-5
Two disadvantages of a polyurethane finish on a fabric-covered surface are:
1. They are designed for metal.
2. They are more difficult to repair
52
6-5
Spraying the newer polyurethane materials over a special ________________ _
makes them suitable for use over fabric surfaces.
flexative modified primer
53
6-5
Polyurethane material should be removed from a damaged surface with __________ before a repair can be made.
sandpaper
54
What factors influence painting processes?
Type of material, painting surface, equipment used
## Footnote
Paint and equipment manufacturers provide information to ensure appropriate settings for equipment.
55
Why is following manufacturer's directions important in painting?
To create a finish that is smooth and pleasing to the eye
## Footnote
A quality finish reduces drag and protects the base material from corrosion and abrasion.
56
What is a key difference in finishing metal and composite surfaces compared to fabric surfaces?
The way the existing coating is removed
## Footnote
Fabric aircraft may only need a new coat or replacement of fabric, while metal and composite require complete stripping.
57
What are the three basic techniques for stripping paint?
* Chemical
* Mechanical
* Pyrolytic
58
What is the preferred method for stripping paint from metal parts?
Chemical paint stripper or air blasting with abrasive material
## Footnote
Mechanical methods are preferred for composite materials to avoid damaging resins.
59
What is the risk of using chemical paint strippers on fiberglass?
They can soften the resins in most fiberglass components
60
What should be done before stripping an aircraft?
Put it in an area where fumes will be filtered and vented away
## Footnote
Proper disposal of any air-filtering element is also important.
61
What is the purpose of masking parts of an aircraft before stripping?
To protect sensitive areas like windshields, windows, and plastic components from stripper
62
How should a stripper be applied to the surface?
Apply a thick layer with a brush without rubbing it in
## Footnote
Covering with polyethylene sheeting prevents solvents from evaporating.
63
What should be done after the stripper has worked into the surface?
Remove it with hot water or a steam cleaner
64
What is the consequence of premature removal of the stripper?
Usually provides poor results
65
What should be used to scrub the surface after stripping?
Warm water, good detergent, and a Scotch-Brite pad
66
What is essential to do with all waste sludge and paint after stripping?
Properly dispose of it
67
True or False: Pyrolytic methods are commonly used on aircraft parts.
False
## Footnote
Pyrolytic methods are rarely used due to the risk of damaging the base material.
68
Fill in the blank: Paint strippers remove the finish by penetrating the surface film, either softening it and causing it to swell (__________) or by dissolving it (dope and lacquer).
[enamels, epoxies, and polyurethanes]
69
What should never be mixed when using different brands of paint strippers?
Ingredients used in different brands
70
What is crucial to avoid during the stripping process around sensitive areas?
Spreading the chemical onto sensitive areas
71
What is the most familiar method of removing old finishes and corrosion?
Mechanically blasting an abrasive material or compound against the paint
72
What is one of the most common methods of aircraft paint removal?
Sand blasting
73
What is a major disadvantage of sand blasting?
The violent and aggressive nature of the reaction of the sand against the material
74
What can happen if blasting occurs for too long in one spot?
The metal can become thinner
75
How does sand blasting affect thin-walled metal tubing like engine mounts?
It can reduce the wall thickness to the point of making it not airworthy
76
What type of metal is particularly damaged by sand blasting?
Aluminum
77
What is the alternative to sand blasting that avoids its dangers?
Media blasting
78
What is the most popular method of media blasting?
Using a plastic material
79
What does media blasting accomplish without harming the underlying metal?
Removes the old finish and surface corrosion
80
What is a critical aspect of the blasting systems used in media blasting?
They provide both the blasting action and remove the residue
81
What must be done with waste materials from media blasting?
They may require special handling due to potentially hazardous contents
82
What is essential for proper preparation during stripping operations?
Masking many items for safety and to prevent contamination
83
What types of additional blasting media can be used?
* Wheat starch
* Sodium bicarbonate
* Glass beads
* Nut shells
* Cornhusks
* Fruit seeds
84
Which lightweight and organic products can be used on thin substrates?
* Fruit seeds
* Wheat starch
85
What common problem can develop when polyurethane topcoats are improperly applied?
Filiform corrosion
86
What is the appearance of filiform corrosion?
A long, thread-like pattern under the dense film of polyurethane
87
What should be done if corrosion is too advanced?
The metal may have to be replaced
88
What process should be done after all corrosion is removed?
Acid etch the surface
89
What is the purpose of applying a conversion coating after acid treatment?
To change the active aluminum surface into a chemically inert oxide film
90
What should be used to check the airframe and fasteners for strength?
Eddy current or ultrasonic testers
91
What should not touch a cleaned surface before painting?
Bare hands
92
How can corrosion be minimized on an aircraft?
Timely touchup of the aircraft finish
93
What should the quality of materials used to cover the substrate match?
The desired durability, the type of material to be covered, and the desired look.
94
Which type of finishes are best for rigid aircraft?
Glossy finishes, like enamel.
95
What is a crucial consideration when picking finishing materials?
Compatibility of all components.
96
What is the purpose of applying a primer after surface pre-treatment?
To provide a good bond between the metal and the topcoats.
97
What has been the standard primer for aircraft due to its corrosion resistance?
Zinc chromate.
98
Why is the use of zinc chromate decreasing?
It does not provide as good a bond to the surface as some new primers and is hazardous.
99
What type of primer is recommended as an alternative to zinc chromate?
Two-component epoxy primer.
100
What is a wash primer and what does it provide?
A wash primer provides a good bond between the metal and the finish and cures after a half hour.
101
On which materials can wash primer be used?
Aluminum, magnesium, steel, or fiberglass.
102
What should be applied for maximum protection on seaplane or agricultural aircraft?
An epoxy primer over the wash primer.
103
What is critical to the application of the three-component wash primer?
Sufficient moisture in the air to properly convert the acid into a phosphate film.
104
What is the empirical requirement for proper conversion of primer?
63 grains of water for every pound of dry air.
105
How can one determine if there is sufficient moisture in the air?
Using a psychrometric chart comparing wet and dry bulb temperatures.
106
What happens if there is not enough water in the air for proper conversion?
The finish will trap active acid against the metal surface, leading to corrosion.
107
What is the primary component of the thinner used for wash primer?
Alcohol.
108
What should be added to the thinner when humidity is between 35 and 63-gpp?
One ounce of distilled water for each gallon of thinner.
109
What should be added to the thinner if humidity is less than 35-gpp?
Two ounces of distilled water for each gallon of thinner.
110
What can happen if acrylic lacquer is applied over improperly cured wash primer?
Moisture can penetrate the film, unite with free acid, and cause blistering.
111
What temperature and humidity range is recommended for applying modern two-component wash primer?
59 to 86 degrees Fahrenheit and 30% to 85% relative humidity.
112
What is the maximum amount of thinner to primer ratio?
Never more than eight parts of thinner to four parts of primer.
113
What are high performance aerospace coatings developed for?
The special needs of modern jet aircraft
114
What is the expected lifespan of airframes in today's military and commercial aircraft?
20 to 30 years
115
What are the main components of aerospace coatings?
Pigments, resins, solvents, and additives
116
What role do pigments play in paints?
Develop color and provide specific qualities such as light and heat reflectance
117
What is the function of resins in aerospace coatings?
Bind the pigments together to form a film
118
Name two types of polymers that resins in aerospace coatings may consist of.
* Epoxies
* Polyurethanes
119
What is an epoxy coating?
A two-part system consisting of a base and an activator
120
What are the typical mix ratios for epoxy coatings?
2:1 or 1:1
121
What advantages do epoxy primers provide?
* Maximum environmental protection
* Excellent flexibility
* Resistance to fluids, Skydrol®, and corrosion
122
On what substrates can epoxies be used?
* Aluminum
* Composite substrates
123
Which aircraft's coatings have been selected from PPG®/PRCDeSoto?
Boeing's new 787 Dreamliner
124
What types of spray application equipment are epoxy coatings compatible with?
* HVLP
* Airless
* Electrostatic spray systems
125
Why is surface preparation important before applying epoxy?
For good adhesion, chemical resistance, corrosion resistance, and appearance
126
What is induction time in the context of epoxy application?
The waiting period after mixing the base and activator that allows polymerization
127
What is the typical tack-free time for epoxies at 75°F and 50% relative humidity?
2.5 hours
128
How long does it take for epoxies to dry to fly?
48 hours
129
What is the full cure time for epoxies?
Seven days
130
What is one of the most durable and attractive topcoats for high-speed, high-altitude aircraft?
Polyurethane system
## Footnote
Polyurethane is known for its hard, chemically resistant finish, ideal for hostile environments.
131
What is the solids content of polyurethane compared to acrylic lacquers?
Up to 60%, twice that of acrylic lacquers
## Footnote
This high solids content contributes to its durability.
132
What gives polyurethane finishes their characteristically high gloss?
Slow-flowing resins
## Footnote
The resins continue to flow until they form a flat surface.
133
True or False: Polyurethane paints are resistant to Skydrol® hydraulic fluid.
True
## Footnote
Skydrol® is known to be highly corrosive.
134
How can the drying time of polyurethane paints be shortened?
By increasing the percentage of catalyst added to the resin
## Footnote
However, too much catalyst can lead to a brittle film.
135
What is the effect of acetone on polyurethane finishes?
Minimal effect
## Footnote
Polyurethane is resistant even to potent solvents.
136
Fill in the blank: The primer used under a polyurethane topcoat is a _______ part of the system.
Critical
## Footnote
Improper curing of wash primers can cause filiform corrosion.
137
What is the induction time in the context of polyurethane?
The time allowed for the material to begin curing after mixing
## Footnote
This is between fifteen to thirty minutes.
138
What is the purpose of a viscosity cup when working with polyurethane?
To determine the viscosity for spraying
## Footnote
The time for the liquid to break is measured in seconds.
139
What is a major difficulty when applying a polyurethane finish?
It is easily sprayed on too thick
## Footnote
This can cause cracking at skin lap joints.
140
How long should polyurethane be left before taping over it?
At least 24 hours
## Footnote
It is normally dry enough to tape in about five hours.
141
What happens if a can of catalyst remains open for too long?
It may absorb moisture and start the reaction
## Footnote
The can may swell up and burst.
142
What is the pot life of a catalyzed material like polyurethane?
About six to eight hours
## Footnote
After this time, the material is no longer usable.
143
What does repainting an aircraft with polyurethane paint usually include?
Picking an entire process system
## Footnote
This includes all metal preparation chemicals, primers, thinners, and additives.
144
What advantages do acrylic urethanes have?
Easy to apply and nearly as durable and chemical resistant as polyurethane
## Footnote
They are often used as clear coats over color coats.
145
What types of areas on aircraft require special finishes?
Wing walks, instrument panels, battery boxes
## Footnote
These areas have specific requirements due to their functional roles.
146
What is the purpose of high-visibility finishes on aircraft?
To make aircraft more visible on the ground and in the air
## Footnote
These finishes are typically applied to wing-tips, cowlings, empennage, or fuselage bands.
147
What is the base coat used for high-visibility finishes?
A white, reflective base coat
## Footnote
This base coat enhances the visibility of the colored pigments applied over it.
148
What is the function of the clear topcoat in high-visibility finishes?
To retard fading of the vivid transparent pigments
## Footnote
The topcoat absorbs ultraviolet light.
149
What is a wrinkle finish used for?
Instrument panels, electronic equipment, parts subject to rough treatment
## Footnote
Wrinkle finishes provide a durable surface that withstands handling.
150
How is a wrinkle finish created?
By using fast drying oils that shrink as they dry, forming wrinkles
## Footnote
The size of the wrinkles depends on the formulation of the material used.
151
What are the two types of wrinkle finish?
One that cures by heat (baked) and one that dries in the air
## Footnote
Air-dry finishes are softer and not recommended for high-wear areas.
152
What is flat black lacquer used for?
Durable, non-reflective coating for instrument panels and glare shields
## Footnote
It should be applied thinly to avoid glossy spots.
153
What is wing walk compound made of?
Sharp-grained sand mixed with tough enamel material
## Footnote
This creates non-slippery surfaces for wing walks.
154
What is the purpose of acid-proof paint on aircraft?
To prevent corrosion in battery boxes and surrounding areas
## Footnote
Acid fumes and spills can damage the metal.
155
What is Alodine?
A brand name for a chromate conversion coating process
## Footnote
It provides corrosion protection and helps paint adhere well.
156
What is the difference between chromate conversion coating and anodizing?
Chromate is conductive and corrosion-resistant; anodizing converts aluminum to non-conductive aluminum oxide with better abrasion resistance
## Footnote
Chromate is generally cheaper and offers good adhesion promotion.
157
What is the recommended finish for battery boxes when using polyurethane?
Polyurethane enamel
## Footnote
It provides superior protection against battery fumes and is resistant to solvents.
158
What is the purpose of float bottom compound?
To protect seaplane floats from abrasion and corrosive elements
## Footnote
It is similar to acid-proof paint and is often an asphaltum product.
159
How can you modify the appearance of the float bottom compound?
By suspending aluminum paste in thinner and spraying it onto the black compound
## Footnote
This allows the aluminum powder to embed in the finish.
160
What may develop seeping leaks around rivets and seams in built-up fuel tanks?
Seeping leaks
161
What is the common name for the resilient, non-hardening tank sealer used in fuel tanks?
Sloshing compound
162
What is the first step in tank preparation before applying a sealer?
Drain the tank and ventilate it thoroughly
163
What should be removed from the tank before sealing?
Gauge sender, vent line fittings, main line screen, and quick drain
164
What should be used to rinse the tank to remove fuel dyes?
Clean white gasoline
165
What is the purpose of pouring acetone or ethyl acetate into the tank during preparation?
To soften the old sealer
166
What should be done after sealing the tank with the sloshing compound?
Drain out the excess compound
167
How long should the tank be dried after applying the sealing compound?
At least 24 hours or 16 hours with low pressure air circulation
168
What should be used to coat the float of the sender unit?
Light grease
169
What should never be done before resealing a tank?
Leave any trace of the old material
170
What is seam paste made of?
Thick zinc-chromate material with organic fibers
171
What is the purpose of seam paste?
To make waterproof joints and leakproof seams
172
What method is effective for paint removal from aircraft components?
Pyrolytic paint removal using high temperature or hot chemical solutions
173
What is the maximum temperature that heat-resistant aluminum paint can withstand?
About 1,200 degrees Fahrenheit
174
What type of paint is designed to protect engine components from high temperatures?
High temperature finishes
175
What is a key characteristic of engine enamel?
Colorfast under high temperatures
176
Fill in the blank: Seam paste is used to join _______ metals.
Dissimilar
177
True or False: Seam paste hardens after application.
False
178
What should be done with threaded holes in the tank during preparation?
Plug all the threaded holes with pipe plugs
179
What is the recommended method for applying sealant around rivets and seams?
Brush sealant into the seams and around the rivets
180
What are organic materials like aircraft woods susceptible to?
Fungus or mildew
181
What should be mixed with a very low solids content alkyd resin to treat wood structures?
Fungicidal materials
182
How long should treated wood structures dry before varnishing?
At least 24 hours
183
What is spar varnish primarily made from?
Phenolic modified oil
184
How does spar varnish cure?
By oxidation
185
What type of film does spar varnish produce?
A tough, highly water-resistant film
186
What must be completely removed from circuit boards before soldering?
Spar varnish
187
What type of oil is used to protect the inside of tubular structures in aircraft?
Tube oil
188
What should be done after forcing tube oil into each tube section?
Drain the oil out and plug the holes
189
What is the purpose of thinners and reducers in paints?
To make them less viscous for spraying
190
What should be used to thin nitrate dope and nitrocellulose lacquers?
Nitrate dope thinner
191
What indicates that a dope film is nitrate when using nitrate dope thinner?
The film softens immediately
192
Can butyrate dope thinners be used in nitrate dope?
No
193
What is the recommended mixture ratio for retarder to regular thinner?
One part retarder to four or five parts regular thinner
194
What is the maximum ratio of retarder to thinner that will be beneficial?
One part retarder to three parts thinner
195
What type of thinner should be used for airshow-quality fabric finishes?
Anti-blush thinner
196
What is a common use for acetone in aircraft painting?
To remove lacquer finishes
197
What effect does acetone have on acrylics or lacquers set in spray guns?
It softens them
198
What is recommended to ensure the quality of acetone used?
Use only virgin acetone
199
Fill in the blank: A rot-inhibiting sealer, as any fungicide or mildewcide, is _______.
Poisonous
200
What is the appearance of the transparent coating used in spar varnish?
Light amber cast
201
What is the primary function of a retarder in dope spraying?
To prevent blushing in high humidity
202
What is a good practice after applying several coats of dope for a smooth finish?
Sand with number 600-grit paper between each coat
203
What should be done to a surface after using a paint stripper?
Wash down to remove wax
204
What type of coating is often used to protect electronic components?
Topcoat of spar varnish with fungicide
205
What is Rejuvenator primarily composed of?
Potent solvents and a plasticizer
## Footnote
Tricresyl-phosphate (TCP) is a common plasticizer used in rejuvenators.
206
What is the function of Tricresyl-phosphate (TCP) in rejuvenators?
It is a permanent, somewhat fire-retardant plasticizer that softens old dope and flows cracks together.
207
What should be done if a fabric job has been interrupted during finishing?
Spray on a coat of rejuvenator to soften the dope and then spray on the color coats.
208
What type of putty is recommended for filling cracks or low spots in wood skins?
Nitrocellulose spot putty.
209
What should be ensured when using spot putty?
Defects that may cause a loss of structural strength are not covered up and hidden.
210
What type of spot putty should be used if the skin is covered only with a film of enamel?
Enamel spot putty.
211
What is the purpose of using enamel spot putty?
To prevent the solvents in the putty from lifting the film.
212
What is the function of a sanding surfacer?
To fill surface irregularities with a material that can be sanded smooth.
213
What should be applied after using the filler on wood or fiberglass structures?
A sanding surfacer.
214
What is the foundational step in the refinishing process of an aircraft?
Preparation of the surface of an aircraft
## Footnote
This step is crucial for ensuring proper adhesion and finish quality.
215
Name the three basic techniques for stripping paint.
* Chemical
* Mechanical
* Pyrolytic
## Footnote
Each technique has its own methods and safety considerations.
216
What precautions must be taken when using chemical strippers?
* Proper ventilation
* Use of protective equipment
* Compliance with EPA regulations
## Footnote
Chemical strippers often contain toxic chemicals that pose health risks.
217
What is media blasting?
A type of compound blasting that removes old finishes and corrosion without harming the underlying metal
## Footnote
Common media used include wheat starch, glass beads, nut shells, and plastic.
218
What is the purpose of a conversion coating on aluminum?
Changes the aluminum into a chemically inert oxide film
## Footnote
This prevents filiform corrosion and allows primer adhesion.
219
What is a wash primer?
Provides a good bond between metal and applied finish and cures quickly
## Footnote
This allows a topcoat to be applied shortly after application.
220
List some aircraft surface finishing materials.
* Synthetic enamels
* Acrylic lacquer
* Polyurethane
* Acrylic urethanes
## Footnote
Polyurethane finishes are noted for their durability and attractive appearance.
221
When should specialty finishes or surface treatments be used?
In situations where traditional paint finishes cannot be used or will not work
## Footnote
Examples include instrument panels, battery boxes, and non-slip surfaces.
222
What are examples of specialty finishes and treatments for specific aircraft surfaces?
* Acid-proof paint
* Fuel tank sealer
* Wrinkle finish
* Spar varnish
* High-temperature finishes (engine enamel)
## Footnote
These finishes are designed for specific environmental conditions.
223
What are thinners and reducers used for in aircraft finishing?
To make dopes, enamels, and lacquers less viscous for spraying
## Footnote
This helps achieve a smoother application.
224
What is a rejuvenator used for in fabric-covered aircraft?
To soften the dope on the surface so that interrupted fabric finish work can be completed
## Footnote
This is important for maintaining the integrity of the fabric finish.
225
6-18
The three basic techniques for stripping paint from metal surfaces are:
1. chemical
2. mechanical
3. pyrolytic
226
6-18
The potent, possibly toxic ingredients in chemical strippers must be used with care to prevent:
1. personal injury
2. aircraft damage
227
6-18
The use and disposal of chemical strippers is strictly regulated by the ___________ and _____.
Environmental Protection Agency (EPA)
Occupational Health and Occupational Safety and Health Administration (OSHA)
228
6-18
Parts of an aircraft surface that must not be touched with paint stripper may be masked with:
1. aluminum tape (or foil)
2. polyethylene sheeting
229
6-18
Paint stripper should be brushed on in a _________ (thick or thin) layer.
thick
230
6-18
Stripper residue is cleaned from an aircraft surface with __________ or _____.
hot water
steam
231
6-18
Sand blasting _____ (is or is not) a good method for removing paint from aircraft structure or parts.
is not
232
6-18
New media blasting systems use __________ material to remove the old finish and surface corrosion.
plastic
233
6-18
Filiform corrosion may occur under the dense film of __________ (polyurethane or acrylic) topcoats.
polyurethane
234
6-18
A(n) __________ coating changes the surface of an aluminum alloy into an oxide film that is chemically inert and will not allow filiform corrosion.
conversion
235
6-18
Two common primer materials are:
1. zinc chromate
2. epoxy
236
6-18
Most high-volume production all-metal aircraft are primed with a(n) __________ primer.
wash
237
6-18
Wash primer is made up of these three components:
1. primer
2. acid
3. thinner
238
6-18
Wash primers should be applied with a maximum film thickness of __________ mil.
0.3 mil (0.0003 in or 0.0076mm)
239
6-18
If the topcoat is not applied over the wash primer within ____ hours, another coat of primer must be applied over the first one.
eight
240
6-18
About the most critical aspect of the application of wash primers is the necessity to have sufficient __________ in the air to properly convert the acid into a phosphate film.
moisture
241
6-18
Acrylic lacquer has a __________ (high or low) solids content.
low
242
6-18
The best finish produced by an acrylic lacquer will result from (circle a or b)
A. A few heavy coats of finish sprayed on.
B. Several light coats of finish sprayed on.
B
243
6-18
The most durable finish system and the one that gives the most pleasing appearance is produced by the __________ system.
polyurethane
244
6-18
__________ primer may be used under a polyurethane topcoat, but if it is not properly cured, it may cause fi.lifonn corrosion.
wash
245
6-18
After mixing polyurethane with its catalyst, it must be allowed to stand for 15 to 30 minutes. This is called the __________ time of the material.
induction
246
6-18
The viscosity of a thinned finishing material is determined using a(n) _____.
viscosity cup
247
6-18
A polyurethane finish is usually dry enough to be taped after __ hours of drying time, but it is best to wait _____ hours.
1. 5
2. 24
248
6-18
The time between the mixing of a catalyzed material and the time it has set up too much for it to be used is called the _________ life of the material.
pot
249
6-18
High visibility finishes consist of three layers: a __________ base coat
a coat of ______________ and an _____ - _______ topcoat.
white reflective
transparent pigment
ultraviolet absorbing
250
6-18
An acid-proof finish, far superior to asphaltum or bituminous paint, is a good coat of __________ enamel.
polyurethane
251
6-18
Zinc chromate paste that is used for making leak-proof seams __________ (will or will not) harden.
will not
252
6-18
__________ oil is used to protect the inside of the tubular structure in aircraft fuselages, empennage structure, and landing gear.
Linseed
