I tested QB fuel tanks in several ways: Baloon test – test the circumference over 24 hrs Soap test high concentration of washing up liquid – look for bubbles Manometer test – 700 mm column of water. Look for change at constant temp and atmospheric pressure All tests are tempo and pressure-dependent. Probably the manometer is the most reliable if done the same temp to the same temp over x hrs. I pressured the tank to about 700 mm (using my lungs) and watched for a change over 24 hrs. The pressure initially changes as the temperature of the air equalises. In my case, both tanks were absolutely fine no leaks whatsoever. Less impressive were the 2 rivet tails found in each tank. Anyway managed to remove them out through the filler cap. Talking of filler caps. My QB tank has a ‘feature’. The filler cap receptacle is not aligned correctly. Attaching the fuel tanks to the wings took a long time, to align and figure out how the brackets go.
More