Tank test w/ balloons

Finished the tanks, fixed two small leaks. I connected plastic tubing to the vent to pressurize the tanks. It was fine for finding the leaks but now that they are fixed, there is a leak around the vent line outlet and the tubing. Tried pro-seal, plumbers putty, tape, etc. Can't get it to seal.

So I tried to use balloons. Same issue. Cannot for the life of me get the stupid balloons to stop leaking where they go onto the vent line outlet. Tape, string, safety wire, etc.

Any suggestions?

Some balloons have pretty thick walls and take quite a bit of pressure to inflate. Condoms work. They take much less pressure to inflate and you don't need much to find leaks. I used small rubber bands to seal them to the vent fitting.

JonJay said:

Condoms work. They take much less pressure to inflate and you don't need much to find leaks.

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I had to laugh. I can see it now - trying to explain to the wife... "Really honey, they're for the airplane..."

NavyS3BNFO said:

I had to laugh. I can see it now - trying to explain to the wife... "Really honey, they're for the airplane..."

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Gives new meaning to your "aluminum mistress" I suppose

I used a small zip tie and tape. That worked for me.

JonJay said:

Gives new meaning to your "aluminum mistress" I suppose

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Hey- I resemble that remark!!

Lots of rubber bands worked for me. I bet F4 Tape - Self-Fusing Silicone Tape could help.

Tank test

Condoms, no it's not too funny as they were accepted practice since the early 1980s. They are better than any balloon as they will rupture befor the tank is distorted and provide enough pressure to show any leaks. Rubber bands work to hold them on, well the non lubricated kind anyway. Get the plain Jane Trojan kind, 3 pack as you might blow one on your first inflation. The last plane I built I purchased some from a very nice pretty young girl at the local pharmacy. I explained what they were for and she replied "I've heard a lot of stories,but this is the best yet". Then the usual eye roll. A couple of days later I took my iPad with pictures to show her and the pharmacist, a hot rod builder just about ready to weld up his gas tank came over and was ecstatic and wondered why no one in the hot rod world had thought of it. Yep, condoms have worked for many years on the RV tanks. Merry Christmas.

I used party balloons. I think I put a wrap of duct tape around and then used safety wire. Pull the balloon down onto the stem as much as you can. I had some trouble sealing this too.

Used two wraps of electrical tape and a zip tie. Good news bad news, balloon sealed but found two leaking rivets.