Apply Fabric Finishing Materials Flashcards
Why should wooden wing spars be finished with transparent varnish?
The transparent finish allows any decay or rot that develops in the wood to be detected
Why is retarded used in dope when the dope is being sprayed in humid conditions?
The retarded slows the drying of the dope and keeps it from blushing.
When an aircraft is being recovered, 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 two basic types of dope used on fabric-covered aircraft?
Nitrate dope and butyrate (cellulose acetate butyrate, or CAB) dope
What kind of dope is used on polyester synthetic fabric that has been heat-shrunk on an aircraft structure?
Nontautening butyrate dope
Why are some portions of the structure of an aircraft dope proofed before they are covered with fabric?
Dope proofing keeps the fabric from sticking to the structure when the first coat of dope is applied. The fabric normally sags enough to touch the structure before it begins to pull taut
What is meant by dope blushing, and what causes it?
Blushing is a condition in dope finished in which moisture from the atmosphere condenses on the surface and causes some of the callouse to precipitate from the finish. Blushing leaves a porous, dull, and weak finish
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 retarded to two parts 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 doped applied
What is a rejuvenator?
A slow-drying finishing material that has potent solvents and plasticizers that soften a dried surface film and restore resilience to the film
Does rejuvanator restore strength to the fabric?
No, it only restores resilience to the finish
Why is the first coat of a dope brushed onto the fabric?
To ensure thorough penetration and encapsulation of all of the fibers
What is the general reason for runs and sags in a finish that is being sprayed onto a flat surface?
Too much dope is being applied. The film is too thick
What is the most common cause for dope roping?
The dope was improperly thinned or it was too cold
What causes pinholes in a dope finish?
Excessive atomizing air pressure on the spray gun
