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Airframe
AIRCRAFT FINISHES
Question | Answer |
---|---|
Why should wooden wing spars be finished with a transparent varnish? | The transparent finish allows any decay or rot that develops in the wood to be detected. |
Why is retarder used in dope when the dope is being sprayed in humid conditions? | The retarder slows the drying of the dope and keeps it from blushing. |
What is used as a protective finish for the inside of steel tubing? | Hot linseed oil. |
How thick should a coat of wash primer be that is used on an aluminum alloy aircraft structure? | It should be thin enough that it does not hide the surface of the metal. |
What happens to an enamel finish when paint remover is applied to it? | The enamel softens and swells so that it pulls away from the surface of the metal. |
What should be done to an aircraft surface that is covered with paint remover to give the remover the maximum amount of time to soak into the old finish? | The surface should be covered with a piece of polyethylene sheeting such as a paint drop cloth. This will keep the solvents from evaporating before they have time to penetrate the paint film. |
When mixing epoxy paint, should the converter be added to the resin or the resin to the converter? | The converter should always be added to the resin, never the resin to the converter. |
What is the general reason for runs and sags in a finish that is being sprayed onto a flat surface? | Too much paint is being applied. The film is too thick. |
What can be done to remedy blushing that has formed on a doped surface that has just been sprayed? | Spray a very light mist coat of a mixture of one part retarder to two parts of thinner over the blushed area. Allow it to dry and spray on another coat. If this does not remove the blush, the blushed dope will have to be sanded off and new dope applied. |
How can a vinyl film decal be removed from an aluminum alloy surface? | Place a cloth saturated with cyclohexanone or MEK over the decal until it is softened, and scrape it off of the surface with a plastic scraper. |
What safety precaution must be observed when sweeping a paint room that has dried dope or lacquer overspray on the floor? | The floor must be wet down with water before it is swept. Static electricity from dry sweeping can cause a fire. |
When an aircraft is being re-covered, when is fungicidal dope applied to the fabric? | With the first coat of dope that is brushed into the fabric. |
What will happen if dope is sprayed over an enameled surface? | The thinner in the dope will penetrate the enamel surface and cause it to swell. |
What are three types of primer that may be used when painting an aircraft? | Zinc chromate primer, wash primer, and epoxy primer. |
How is the finish removed from a fiberglass aircraft component that is being repaired? | The finish must be sanded off. Paint remover can soften the resin of which the component is made. |
What are the two basic types of dope that are used on fabric-covered aircraft? | Nitrate dope and butyrate (CAB) dope. |
What kind of dope is used on polyester synthetic fabric that has been heat-shrunk on an aircraft structure? | Nontautening butyrate dope. |
What type of thinner is used with zinc chromate primer? | Toluol or toluene. |