I new tonight to this forum, but an old Airstreamer ( 41 years )
I had a leak in the back where an upper outer panel had been replaced, every thing looked good but it leaked, I tryed tube type sealers but I never found the right spot.
I was in Camping World about a month ago, and found a sealer called Capt. Tolley's Creeping Crack Cure, it sounds expensive at $8.00 for 2oz, but I love this stuff
It is a very thin liquid, you put a drop up high on the seam and it runs down like a drop of skim milk until it finds a hairline crack, then it disapears, wait about 30-60 min for it to thicken, then do it again, after a while the drop will run a long ways down the side, you can wipe off the wet stuff with a slightly damp cloth.
I have gone over the main seams on the whole trailer with 1/2 of the bottle!
I have watched this stuff go into places that looked perfect, so there must have been a crack, I have even seen it go up into a horizontal seam from the bottom,
If you have a leak in the skin you have got to try this stuff