Hi all, looking for some suggestions to potentially apply a liner to the inside of my aluminum fuel tank on my TT replica. It's been beat up a bit, but I like it as it adds some "patina" to the machine. I've had the underside modified to work on my frame/carburetor configuration. Even though the tank was pressure tested by the fabricator (who is a welding expert and used the tig process) I think a minute amount of fuel is getting out of the tank somehow. It certainly isn't a "leak", a "weep", or even a "sweat" of fuel -- I've just noticed a trace amount of fuel residue underneath the seam on the right hand side. All that I've seen are products that are designed to work with steel tanks. I'm wondering if anyone has a suggestion for a product (perhaps aviation or marine application) that would work in this case. I might just get it re-welded, but the amount of fuel that is "coming out" is miniscule. From what I understand, a lot of the oldtimers liked to oxyacetelyne weld aluminum tanks, as the process (as hard as it is to do properly) was less likely to lead to microscopic pinhole leaks than tig. Best I can tell, this tank had an interesting life -- it's been gas welded, mig welded and now tig welded since it left the factory back in the 80s!

I think a sealer should be a last resort. If the welder is an expert, let him get to the bottom of the problem and fix it. Even the best sealers break down eventually and cause other problems. For me, one of the purposes of an alloy tank is to never have to seal it or worry about rust. I use something called Caswells as it seems to be the better of what is available. I still am not happy using it, but it beats a whole tank reconstruction. I'm referring to a fiberglass tank. Lou

Put Green Loctite on the outside & pull a vacuum from the inside. Green loctite will seal pinhole. Make you use the loctite primer beforehand.