Leaking fuel tank

[CharlieZulu]

So I've recently discovered a fuel leak in one of my tanks after noticing some fuel coming from the wing. My tanks are scratch built. Not sure what the current tank design is but these are riveted. They are about 15 years old and it looks like the main culprit is a rivet on the back wall, although there is evidence of some other small leaks. One of the issues is that the seams have been sealed with some sort of sealant meaning it's hard to know how many problem areas lie under the silicone. So what would you guys suggest?

1) add a bit of pressure to the tank and use some sort of fuel resistant epoxy sealant to patch up what I can see.
2) similar to above but remove all the old sealant as well. I figure if there are small leaks and the tank is out it may be a good time to replace
​​​​​​3) bite the bullet and buy new tanks from avipro. I guess it depends on how confident I should be about being able to fix it properly...

What ​​​do you guys think?

[Battson]

New tanks are going to be the best solution in the long run. New tanks are NOT expensive, by aeroplane standards.

[slscott715]

I second what battson says. If you're on a shoestring budget, you could probably get by, at least short-term, by touching up the sealant. Success with that method depends greatly on how the tanks were constructed (i.e. sealant used, rivet spacing, etc). If you do decide to touch them up, make sure you clean areas you intend to seal very well and use the proper sealant such as ppg's pr1776. The stuff is very messy, so keep some alcohol or acetone nearby for clean-up.

[CharlieZulu]

Thanks guys. I've emailed Mark. Draining the tanks and removing the tank was a pain so I think a long term solution is the way to go.

[marcusofcotton]

Absolute agreement from here, otherwise you'll likely be back at them by the sounds of it. This is where close adherence to plans is nice, having the ability to get parts from Mark is great when desired.

[Juan C. Casabuono]

http://www.donmaxwell.com/publicatio...hem%202-05.htm

PRC 1422 sealant, not epoxy, clean and apply from outside with tank under vacuum.

[jaredyates]

Bob's plans have always called for welded 5052 aluminum tanks, though other things have certainly been done. As I recall, the factory tanks are leak-checked in production, but the same guy has welded so many of them that they almost never leak during the check.