I don't have any pics from the inside; I will try to take some this weekend but I keep the trailer in a storage so you won't see much scenery through the windows ha ha...
When I bought the trailer from Bates the taillights were horribly corroded (like almost ALL new Airstreams I've seen on lots...the most recent are the worst, they have this yellowing bubbly corroded appearance that looks like cat pee solidified on the lights).
One of the purchase agreements for my trailer was that Airstream would supply new light assemblies which they did. But, I've never installed them. They are clearcoated, but you KNOW what would happen to them if they were installed...filiform time! I didn't want to go on the "quest" to find out what kind of clearcoat wouldn't peel or corrode. I'm going to have them powdercoated chrome sparkly blue to match my truck wheels and my trailer trim and see what they look like on there. Might look horrible, but it's just for fun as I've repaired my original light assemblies last year to perfection by sanding...and sanding...sanding...sanding...sanding...endless sanding...sanding...cussing...fingers raw...bleeding...sanding...sanding...sanding...non-stop f'in' sanding.
After countless hours of sanding (did I mention sanding???) to remove the filiform I simply polished them. No more filiform...
I took the housings off and stripped them with paint stripper. The Airstream clearcoat came off in thin plastic-like sheets.
At first I did a test area of about 2" x 3". All of my sanding has been done wet, with 3m wet/dry sandpaper. It took forever, but it seemed to work. In order to get through the filiform, I actually had to use 120 grit sandpaper (I was thinking maybe 320 or at the most 220 would at least get rid of it but no) as the filiform really eats deep into the metal. So, on the test area I sanded in stages by hand, going in only one direction per grade of sandpaper. When I would switch from 120 to 220 I would then sand entirely in the opposite pattern, and so on until the last grit. I worked my way down on this little 2" x 3" section for hours going through 120, 220, 320, 400, 600, 800, 1000, 1500
, and 2000 grit. I then polished (rather easily) by hand with a rag and Mother's Power Metal aluminum polish. The results on this test area were mirror smooth and shiny.
There is absolutely no way to remove the filiform on these taillights with ANYTHING less than 120 grit. And, it takes literally hours to get down to where the aluminum isn't pitted anymore. It would be impossible to remove it with 1000 grit. If all you wanted to do was remove the white chalky lines and the superficial corrosion, you can do that with 320 grit...but the pitted indented slightly darkened aluminum will remain. 120 grit is the least harsh grit to use to actually sand past the pits by hand. And, again...it takes hours, just with the 120 grit. Then, 220, 320, 400, 600, 1000, and 2000 followed by hand buffing (or machine buffing if you wish). Even at that point, it will be possible to see pits in the aluminum from the filiform if you didn't go deep enough with the 120 grit.
I taped off everywhere that I didn't want to touch with 120 grit as I didn't want to make unnecessary work for myself; I didn't want to buff out anything that didn't need it. So, only the filiform areas were hit with 120, 220, and 320. I initially sanded the entire casings with 400 only after I had taken care of the filiform areas to 320.
But, anyhoo...eventually they were completely polished, done and perfect looking. Removing filiform thoroughly the right way SUCKS. Did I mention removing filiform sucks? If I didn't, then I just want to say that removing filiform sucks. Sucks bad.
I'm leaving them exposed natural polished aluminum (the same as polishing aluminum rims...no clear coat). That way, any natural oxidation will be easily removed with aluminum polish. The filiform creates deep pits where it spiders under the clearcoat. With no clearcoat, the filiform shouldn't form. Just regular old fashioned aluminum oxidation...which is simple to remove and maintain. They have held up PERFECTLY with no clearcoat, and I've not re-polished them (or done ANYTHING to them) since I reinstalled them last year.
After sealing them, I surrounded the joint with 1/4" chrome trim (the same manufacturer "Cowles Products" as the chrome on the beltline, just thinner). Airstream REALLY liked the trim as it really finishes the lights, and were toying with the idea of incorporating it. I doubt if they will though, as it requires a keen eye and attention to detail to install it straight, true, proper, and competently. If you just slapped it on it would look like hell. I'll try to take a picture of the trim as well.
Here are some pics after I (and my loving girlfriend) polished the assemblies until we had no skin left on our fingers:
This is the ONLY way to fix the taillights and expect them to not turn back into a filiformed mess. Don't clearcoat them...when they get a tiny bit dull (mine haven't yet whatsoever after a year) just wipe them with some aluminum polish for about 3 minutes. Back to perfection. But getting there sucks. Did I mention removing filiform sucks? It sucks. But, once it's gone, it's not hard to maintain the aluminum. Just a quick wipe here and there. Simple and easy.