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I think I Just BLUE my tanks

claycookiemonster

Well Known Member
(Arrested Development Reference. Never mind)

So, my tanks have been my nemesis. I'm not sure why. Finally, after prying the rear baffle off of both tanks and then re-sealing and re-riveting them both, everything looked good. Leak test good. No bubbles. I even borrowed a smoke leak tester from an automotive source, and no smoke. Life is good. Today, in preparation for mounting the tanks on the wings and calling it all good, I did the final test: actual gas in the tanks. Each tank got a gallon or so, and both were set up with baffle side down while we attended to other chores. Everything was fine, until suddenly, both of us smelled gas. There was a puddle beneath one of the tanks, and there was seltzer-like bubbling along a small portion of one tank. That tank was returned to the nose down position in the cradle, and we continued building. After my partner left for the day, I smelled gas anew, and found a puddle beneath the other tank still sitting baffle down.

The skin of the second tank was noticeably pillowed, and the clue bird began circling. When I popped the fuel caps on both tanks, there was a noticeable gust of fuel vapor from each.

Now, the temperature hadn't changed significantly, and the gas had been stored where we were working, but somehow, the fuel in the tanks had vaporized quite a lot and overpressurized both tanks to the point of (I believe) inducing leaks were there had been none before. I now occurs to me that a finished tank is never really completely sealed; there's always the vent line to relieve excess pressure. But, I had sealed all vapor exits and locked the caps to keep fuel from spilling out as I filled and then turned the tanks over to check all sides.

So, if you do actual gas testing, put a hose on one of the fuel tank fittings so that you're testing for fluid leaks, not vapor tightness.

Now, advice from fellow leaky tankers (you know who you are) what are the relative nightmares of the Van's leak repair kit, versus rebuilding new tanks?
 
I am not sure if I ought to offer any thoughts/advise since I am not one of the "fellow leaky tankers" luckily but I really feel for you as I had followed your adventure building these tanks. Honestly, I didn't think it was a good way going your second round but I was glad you had success.

However, IF it was me, for sure I would be going the fixing route by cutting multiple access hole on the back baffle and do a real good job sealing from inside. Heck, after building mine, I thought if I ever build another one I may cut holes in the back from the get go and seal the baffle from inside.

With best wishes
 
Pressure test with Van's leak check kit (~1psi in the tank). Spray soapy water and pinpoint the leaks. Buy the tank repair kits from Van's and get inside where you need to to reseal as necessary. Rinse and repeat until you don't have leaks!

Click on my blog link in my signature, search for "tank repair" if you want more info on fixing leaks. I've fixed a few!
 
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