Aircraft Finishes Flashcards
Name the safety and health precautions to be observed in operating a dope room, including storage of material.
The dope room should be well lighted and ventilated using spark proof motors, lights and switches. All flammable material should be stored in fireproof containers in protected areas. Dope and paint rooms that are not located in a separate building should be isolated from the rest of the building by metal partitions and fireproof doors.
What type of tests can be performed to identify existing paint finishes?
Apply a coat of engine oil to a small area. Nitrocellulose will soften in a few minutes, but acrylic and epoxy will show no effects. If not identified, next wipe down a small area with MEK. MEK will pick up pigment from an acrylic finish, but will not affect an epoxy coating.
What causes blushing, when applying dope or lacquer, and how can it be prevented?
When doping is accomplished under humid conditions blushing is common. Rapid evaporation of thinners and solvents lower the temperature of the surface of the wet dope causing condensation of moisture from the air. The moisture causes a milky white appearance known as blush. The condition may be eliminated by heating the room to decrease humidity, or by using a blush-retarding thinner to increase the drying time. Blushing is also caused by moisture in the air supply, drafts, or changes in temperature.
What is the purpose of using fungicidal dope when finishing aircraft fabric?
To prevent micro-biological deterioration (rotting) of the fabric.
What are the identification marking requirements for United States registered fixed wing aircraft?
The Roman capital letter “N” followed by the registration number must be displayed on both sides of the fuselage, or on both sides of the vertical tail surfaces. The height of the characters must be equal in size and be at least 12 inches, and the characters must be 2/3 as wide as they are high. The exceptions to the width rule are the number “1”, which must be 1/6 as wide as it is high, and the letters “M” and “W”, which may be as wide as they are high. Characters must be formed by solid lines 1/6 as thick as they are high, and the spacing between each character may not be less than 1/4 of the character width.
What are three types of dope used for aircraft finishes?
They are clear dope, semi-pigmented dope, and pigmented dope.
What would happen if dope were used over paint or enamel?
It would have the tendency to lift and remove such materials.
What is applied to metallic surfaces as a corrosion resistant covering before the application of enamel or lacquer?
Zinc chromate primer is normally used for this purpose.
What are the most common methods of applying aircraft finishes?
They are dipping, brushing, or spraying.
What type of paint may be used over any paint system that is in good condition?
Epoxy topcoats will adhere to all the paint systems that are in good condition and may be used general touchup, including touch up of defects in baked enamel coatings.
What is normally the cause of runs and sags in a spray paint finish?
Holding the gun too long in one place causing too much paint to be applied.
What causes an “orange peel” or “pebble” finish?
The spray gun setting, incorrect air pressure, incorrect paint viscosity, and holding the gun too far from the work.
What is used to thin zinc chromate primer?
Toluene.
Which federal regulation prescribes the size and location requirements for aircraft identification numbers?
FAR Part 45
What type of materials should be thoroughly protected when using paint remover?
Synthetic rubber surfaces, aircraft tires, fabric, and acrylics must be protected against possible contact with paint remover.
