Airframe Chapters (Aircraft Finishes)

What is likely to occur if un-hydrated wash primer is applied to unpainted aluminum and then about 30to 40 minutes later a finished topcoat, when the humidity is low. a) corrosion. b) a glossy, blush-free finish. c) a dull finish due to the topcoat 'sinking in' t primer that is still too soft.

a) corrosion. Covered with a dense film of a finish such as a polyurethane, there is a good probability that filiform corrosion will form under the polyurethane.

What is the usual cause of runs and sags in aircraft finishes? a) too much material applied in one coat. b) material is being applied too fast. c) low atmospheric humidity

a) too much material applied in one coat. Runs and sags in the surface of paint that had been sprayed are normally caused by applying too much material in one coat.

Which type of coating typically includes phosphoric acid as one of its components at the time of application? a) wash primer. b) epoxy primer. c) zinc chromate primer.

a) wash primer Wash primer is a two-part primer that contains phosphoric acid to etch the surface of the metal to improve the bond between the surface and the topcoats.

What is likely to occur if hydrated wash primer is applied to unpainted aluminum and the about 30 to 40 minutes later a finish topcoat, when the humility is low? a) corrosion. b) a glossy, blush-free finish. c) a dull finish due to topcoat 'sinking in' to primer that is still to soft.

b) a glossy, blush-free finish.

Which defect in aircraft finishes may be caused by adverse humidity, drafts, or sudden changes in temperature? a) orange peel. b) blushing. c) pinholes.

b) blushing Blushing is a condition in dope or lacquer finishes in which moisture from the atmosphere condense on the surface and cause some of the cellulose to precipitate from the finish. Blushing leaves a porous, dull and weak finish. Blushing may be caused by the temperature being too low, the humidity being too high, or by drafts of sudden changes I temperature.

Fungicidal dopes are used in aircraft finishing as the a) first, full bodied, brushed-on coat to prevent fungus damage. b) first coat to prevent fabric rotting and are applied thin enough to saturate the fabric. c) final, full-bodied. brushed-on coat to reduce blushing.

b) first coat to prevent fabric rotting and are applied thin enough to saturate the fabric. Fungicidal dope is used for the first coat applied to cotton or linen aircraft fabric. it is thinned enough to allow it to thoroughly saturate both side of the fabric. The purpose pf fungicidal dope is to retard the formation of fungus and mold which would cause th fabric to rot.

A correct use for acetone is to a) thin zinc chromate primer. b) remove grease from fabric. c) thin dope.

b) remove grease from fabric. Acetone is a fast evaporating dope solvent that is suitable for removing grease from fabric prior to doping. It is also used for cleaning paint spray guns and as an ingredient in paint and varnish removers.

What is used to slow the drying time of some finishes and to prevent blush? a) reducer. b) retarder. c) rejuvenator.

b) retarder Retarder is a special type of thinner that dries slowly. It is used in dope and lacquer to slow its drying time. The slower drying time prevents blushing and provides a smoother finish.

Which of the following is a hazard associated with sanding on fabric covered surfaces during the finishing process? a) overheating of the fabric/finish, especially with the use of power tools. b) static electricity buildup. c) embedding of particles in the finish.

b) static electricity buildup. When dry-sanding a fabric-covered surface, be sure to electrically ground it to a cold water pipe or some other good electrical ground. Rubbing the sand[paper over the surface will generate enough static electricity that a spark could be caused to jump and ignite the highly flammable fumes inside the structure.

Before applying a protective coating to any unpaid clean aluminum, you should a) wipe the surface with avgas or kerosene. b) remove any conversion coating film. c) avoid touching the surface with bare hands.

c) avoid touching the surface with bare hands. It's important when preparing a bare metal surface for painting that, after it has been cleaned you do not touch it with your bare hands. There is enough oil on the surface of you skin that it can contaminate the surface enough that the finish will not adhere.

If masking tape is applied to an aircraft such as for trim spraying, and is left on for several days and/or exposed to heat, it is likely that the tape will a) not seal out the finishing material if the delay or heating occurs before spraying. b) be weaken in its ability to adhere to the surface. c) cure to the finish ad be very difficult to remove.

c) cure to the finish ad be very difficult to remove. Masking tape should be removed from the surface as soon as the finish has dried to the extent that it is no longer tacky. If the tape is left on the surface too long, it will cure to the finish and be extremely difficult to remove.

Which statement is true regarding paint system compatibility? a) old type zinc chromate primer may not be used directly for touchup of bare metal surfaces. b) Acrylic nitrocellulose lacquers may be used over old nitrocellulose finishes. c) old wash primer coats may be overcoated directly with epoxy finishes.

c) old wash primer coats may be overcoated directly with epoxy finishes. Old wash primer coats may be overcoated directly with epoxy finishes. A second coat of wash primer, however, must be applied to the surface if an acrylic finish is to be applied.

Which properly applied finish topcoat is the most durable and chemical resistant? a) synthetic enamel. b) acrylic lacquer. c) polyurethane.

c) polyurethane This is the most durable of all finishes that are used for modern aircraft. It is noted for its chemical resistance and for its famous 'wet look' that is caused by its slow-out time.

Aluminum pigment I dope is used primarily to a) provide a silver coat. b) aid in sealing out moister from the fabric. c) reflect ultraviolet from the fabric.

c) reflect ultraviolet from the fabric. Aluminum pigmented dope contains tiny flakes of aluminum metal that spread out to form a solid, lightproof film over the coats of clear dope. The aluminum dope prevent the ultraviolet rays from the sun damaging the fabric and the coats of clear dope.