corrosion control (from prepware)

for which of the following reasons would a water break test be conducted?

to make certain that a bare metal surface is thoroughly clean

corrosion should be removed from magnesium parts with a

stiff nonmetalic brush

which properly applied finish topcoat is most durable and chemic resistant?

polyurethane

fayed surfaces cause concern in chemical cleaning because of the danger of

entrapping corrosive materials

A nonelectrolytic chemical treatment for aluminum alloys to increase corrosion resistance and paint-bonding qualities is called

alodizing

If registration numbers are to be applied to an aircraft with a letter height of 12 inches, what is the minimum space required for the registration mark N1683C?

note: 2/3 x height: character width

1/6 x height: width for 1

1/4 x 2/3 height: spacing

1/6 x height: stroke or line width

52 in

intergranular corrosion in aluminum alloy parts

cannot always be detected by surface indications

select the solvent recommended for wipedown of cleaned surfaces just before painting

aliphatic naptha

which of the following are acceptable to use when utilizing chemical cleaning agents on aircraft?

cotton fiber wiping cloths when using a flammable agent and atomizing spray equipment

which of these materials is the most anodic

Magnesium

the lifting of flaking of the metal at the surface due to delamination of grain boundaries caused by the pressure of corrosion residual product is called

exfoliation

when humidity is low, what is likely to occur if hydrated wash primer is applied to unpainted aluminum and then 30 to 40 mins later a finish top coat is applied

a glossy blush free finish

galvanic corrosion is likely to be most rapid and severe when

the surface area of the anodic metal is smaller than the surface area of the cathodic metal

1. in the corrosion process it is the cathodic area or dissimilar cathodic material that corrodes

2. in the galvanic or electro-chemical series for metals the most anodic metals are those that will give up electrons most easily. regarding the above statements

only 2 is true

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 tap will

cure to the finish and be very hard to remove

corrosion caused by galvanic action is the result of

contact between two unlike metals

aluminum pigment in dope is used primarily to

reflect ultraviolet from the fabric

which of the following are desired effects of using alodine (also known and bonderite) on aluminum alloy?

a slightly rough surface and increased corrosion resistance

a primary cause of intergranular corrosion

improper heat treatment

which type of coating typically includes phosphoric acid as one of its components at the time of application?

wash primer

what may be used to remove corrosion from highly stressed steel surfaces?

fine grit aluminum oxide

one way of obtaining increased resistance to stress corrosion cracking is by

creating compressive stresses (via shot peening) on the metal surface

what is the usual cause of runs and sags in aircraft finishes?

too much material applied in one coat

ni cad battery cases and drain surfaces which have been affected by electrolyte should be neutralized with a solution of

boric acid

which of the following is an acceptable first step procedure to help prevent scratching when cleaning a transparent plastic surface?

flush the surface with clean water

select the solvent used to clean acrylics and rubber

aliphatic naphtha

the rust or corrosion that occurs with most metals is the result of

a tendency for them to return to their natural state

why is it important not to rotate the crankshaft after the corrosion preventative mixture has been put into the cylinders on engines prepared for storage?

the seal of corrosion preventative mixture will be broken

before applying a protective coating to any unpainted clean aluminum you should

avoid touching the surface with bare hands

what is used to slow the drying time of some finishes and to prevent blush

retarder

fretting corrosion is most likely to occur

when two surfaces fit tightly together but can move relative to one another

which statement is true regarding paint system compatibility?

old wash primer coats may be overcoated directly with epoxy finishes

which of these materials is most cathodic

stainless steel

which of the following may not be detectable even by careful visual inspection of the surface of aluminum alloy parts or structures?

intergranular corrosion

a primary reason why ordinary or otherwise non approved cleaning compounds should not be used when washing aircraft is because their use can result in

hydrogen embrittlement in metal structures

how may magnesium engine parts be cleaned?

wash with commercial solvent decarbonize and scrape or grit blast

which of the listed conditions is NOT one of the requirements for corrosion to occur?

the presence of a passive oxide film

which of the following are acceptable to use in cleaning anodized surfaces?

aluminum wool and fiber bristle brushes

fungicidal dopes are used in aircraft finishing as the

first coat to prevent fabric rotting and are applied thin enough to saturate the fabrics

when an anodized surface coating is damaged in service it can be partially restored by

chemical surface treatment

which of the following is a hazard associated with sanding on fabric covered surfaces during the finishing process?

static electricity buildup

which defect in aircraft finishes may be caused by adverse humidity drafts or sudden changes in temp?

blushing

caustic cleaning products used on aluminum structures have the effect of producing

corrosion

when humidity is low what is likely to occur if unhydrated wash primer is applied to unpainted aluminum and then about 30 to 40 mins pass a finish topcoat is applied?

corrosion

what should be done to prevent rapid deterioration when oil or grease come in contact with a tire?

wipe the tire with a dry cloth followed by a washdown and rise with soap and water

the interior surface of sealed structural steel tubing would be best protected against corrosion by which of the following?

a coating of linseed oil

a correct use for acetone is to

remove grease from fabric

spilled mercury on aluminum

causes rapid and severe corrosion that is very difficult to control

of the following, when and/or where is galvanic corrosion most likely to occur?

at the interface of a steel fastener and aluminum alloy inspection plate in the presence of an electrolyte