Protective Coating 1

roozle..

I have never heard of the materials You indicated.

The FAA does NOT specify corrosion protection as You were expecting: it is part of the damage protection scheme for structures and systems... and interiors MUST not contribute to structural or systems corrosion. This includes metallic protection schemes and use of non-corrosive non-metallic materials and other chemicals materials [such as fire-proofing impregnants]. These materials must NOT out-gas, cross-link or otherwise transfer corrosive chemistry [clorine, salts, etc]; or otherwise don't encourage corrosive behavior, such as trapping moisture against metal parts [IE: moisture-proof insulation].

Typically "Alodine" [AMS-C-5541] and Epoxy Primer [MIL-PRF-23377, or variations of this primer] are used for aluminum protection.

All non-metallic materials have to be checked for moisture retention, out-gas constiuents, contact chemistry [IE: materials touching sometime cross-link, like rubberbands against certain paints], abrasiveness, fire resistance... etc. This includes "new" and aged" versions of the same materials. Regards, Wil Taylor

Yellow is probably a chem-film.

TTFN

Yes the surface treatment is yellow. Do you have any more infomation regarding this.

Rgs,
Roozle...... Highest Regards,
Roozle

roozle...

It's hard at best, impossible at worst, to diagnose coating-systems without hands-on inspections.

The surface is "yellow" could mean a host of things, based on Your perspective.

a. If this is an aluminum surface that appears to "shimmer" with a "golden-yellow" reflection-tone, it could be alodined or chromic acid anodized... or possibly phosphoric-acid anodized if viewed at an angle.

b. If this is a painted coating it could be an epoxy, polyurethane or enamel primer [in that order] with yellow corrosion-protective pigments... or if the assy is adhesive-bonded, it could be an adhesion promoting epoxy primer.

It could also have a + b on it.

More specific deatails are important. Regards, Wil Taylor