Side triangle window frames

[Flybyjim]

I am ready to glue the door frame and window channels in place. As I look down the road to covering and painting the window frames need to be addressed. It seams that the frames should be painted/powder coated before gluing this all in place. I think I did see a post a while back about covering the frames, looking for your experiences with these frames.

Jim

[Esser]

I left mine bare exept the poly fiber product that attaches the fabric to them. Maybe others have primed. I live in a very dry place so I wasn’t too worried about coating non structural aluminum.

[efwd]

I suppose your thinking "corrosion"? I wouldn't spend money on powder coat myself. I alumaprepped and alodined mine. covered them in fabric.
Eddie

[jrevens]

Jim,

I did the same as Eddie. You don’t want to install the plastic in them until later, after you cover, paint, etc. anyway, and they are finished just like the rest of the structure, however you do that. Mine were covered with Oratex.

[jiott]

I left my triangle frames bare, then epoxy primed them, and finish painted them with the same Aerothane as the fabric in that area.

[David47]

I'm applying Aldine 1201 to mine before I go to covering. They're already bonded in place but I'm not too concerned about corrosion on the inside bonded surfaces because I'm extruding silicon or polysulphide sealant into any gaps before close out.

FWIW..... many years ago an airframe mechanic friend of mine was rebuilding part of the wing of a Cessna 150 so he had the skins off. There was no corrosion proofing at all on the ribs, spars or skin inner surfaces - primer was an option in those days. I know Aluminium has a natural corrosion inhibitor in the form of the Aluminium Oxide that forms on the surface when exposed to air, but that only stretches so far, especially if you're operating in a saltwater or other corrosive environment. Having said that, I'm a great proponent for corrosion protection for Al Alloys, with Alodine as a minimum.

[jrevens]

... I know Aluminium has a natural corrosion inhibitor in the form of the Aluminium Oxide that forms on the surface when exposed to air, but that only stretches so far, especially if you're operating in a saltwater or other corrosive environment. Having said that, I'm a great proponent for corrosion protection for Al Alloys, with Alodine as a minimum.

Pure aluminum, as well as some other alloys like 6061 (used quite a bit on the Kitfox), is much less vulnerable to corrosion than some of the higher-strength alloys, like 2024 and 7075 that are used extensively on many aircraft. There were a few 2024-T3 parts in my kit. That is why there is "Alclad" sheet, which has a very thin layer of pure aluminum on one or both surfaces. Additional protection is still recommended. It's needed between dissimilar metals also. I'm a big proponent of protecting the aluminum too, but I have seen aircraft that spent their lives in our dry climate here in Colorado, had no obvious corrosion protection, and still looked good after many years. If you live on the coast of an ocean, in a humid environment, or fly a float plane, that's not likely to be the case. When building my first airplane (all metal) I Alodined almost everything, inside and out, as well as using zinc chromate primer between faying surfaces. I built a power supply & tank to chromic acid anodize everything I could fit in my tank. You will rarely see factory-built aircraft that have that degree of corrosion protection. Overkill, no doubt.

[Flybyjim]

This is all very good information, yes we all tend to over think, over build, over protect sometimes, I am in the same group.