Completed my RV-12iS fuel tank a week ago, and leak tested today. I initially put a balloon over the filler neck (securely taped), pumped up with air until the balloon inflated. Used a commercial gas leak bubble fluid on every seam and rivet, and had no bubbles. However, the balloon deflated over the next hour. Replaced the balloon with a nitrile glove per KAI, and it again deflated after an hour with no bubbles around the taped-on glove. How long should the balloon/glove stay inflated? Should I use something other than soapy solution to check for leaks after pressurizing?