Tank leak test

Guys,

Closed up the tanks and using balloon method to test. It's been a couple hours and balloon looks the same size. How long should I run the test? I was thinking let it sit overnight and if balloon looks same size, call it good. As usual your thoughts and comments are appreciated.

soapy water

That balloon will change with the air temp
check this

https://youtu.be/BANMqZ35vYw

Cm

Leak test

Probably fine but spray them down with soap solution or a bottle of kids bubbles just to be sure.

Yeah temperature and pressure will cause the balloon to change size. I was wondering about how long should I leave the balloon on.

I know this isn't "approved," but I have my tanks tested at a radiator shop. They have all the fittings, know not to go over .5 psi, and can do in 10 minutes what I MIGHT be able to do in a day. Yeah, I remember having a fitting leak, and wasted more time figuring it out. This way, go in, plug the tanks, submerge them (one at a time) add .5 psi, and look for leaks. Have done two planes that way and am not going back to the balloon. Yes, we found a leak in one tank. If you are careful, you will find every possible leak. I will admit I wouldn't have this done in some shops, but there are good ones out there. Big time saver, and costs almost nothing, $10 for the last one.

Bob