Pressure testing fuel tank

[Av8torTom]

How long should I wait after completion before pressure testing the fuel tank?

[airguy]

At least a couple of days in warm weather for the proseal to thoroughly cure, I moved my tanks inside my house for stable temps and waited a week.

[JimWoo50]

I tried that route and was not convinced that it was a good test and was advised not to put more than one or two pounds of air to the tanks or they could get damaged. So I just put about a gallon of gas in the tank after the proseal cured for a week and stood the tank on each end for a couple of days and level to check for leaks. I figured I already had a gallon container of gas in the garage for the lawn mower so why not my fuel tanks? BTW I had one tank totally leak free and one tank a small seep in the lower seam of the rear baffle which did not manifest itself until after I had installed the tank on the wing. Good Luck to you and Happy Building!

[newimaging]

I did mine the day after. Put 2 balloons, the second one was for the return line option I added to each tank. I pump it up with my bicycle pump until one balloon was inflated, which still showed less than 1psi. That way the balloon pops before you can damage the tank. Then I sprayed everything with soap water. One tank had some tinny bubbles come out of a blind rivet I forgot to cover. After covering that and waiting for about 6 hours I filled it with air again, and everything was tight, no bubbles. Left the balloon on for 2 days, hasn`t changed. I figure I am good to go for now.

[bkthomps]

to rule out having a leaky balloon ( i had a few)

whenever you tie your balloon off on the tank, make another balloon as a standalone control balloon, if both are deflated it's atmospheric/conditions or bad balloon