Fuel leak vanished...

...passed balloon test, soapy water, and windex but no bubbles with tank pressurized, what now??

There was a leak because a small circle of blue showed up along an aft baffle rivet line. This all came about a couple weeks ago when the tank vent was blocked and OAT rose to 85 or so. When under pressure the tank leaked profusely but stopped when pressure was released, it did not show any leakage until after 48 hours and then it was a very minor seep.

Well i found the little buggers today!!

Last night a thought popped into my brain, try some kids bubble making stuff from Toys R Us. I don't know where the idea came from but I bought a small bottle of it for 99 cents.

The tank was re-pressurized to max with a large balloon. The balloon had lost very little size over night.

The kids bubble making stuff is much thicker than soapy water. I applied it to rivet heads with a small brush and instantly there appeared a tiny growing bubble at 6 or 7 rivets along a line where I had thought the proseal bead had been broken. Amazing. Soapy water in the same area did not reveal the tiny leaks.

I've opened the tank and will apply a new bead inside tomorrow. Hope to have the airplane flying in a couple days - can't stand a grounded air plane.

But I will do another kids bubble test to make sure the leaks are sealed.

Idea

Good idea. Post it to the "Tips" section.

Just did the Super Miracle Bubbles test after proseal yesterday - no leaks!!
Tank reinstall begins - glad that matter is resolved.

The only thing better than bubble solution is some stuff called "Snoop", from Swagelok, available on Amazon and elsewhere. Unlike soapy water, there are no bubbles when you spray or brush it on, unless there's a leak.

+1 on "Snoop." Electricians at the power plant I used to work at used Snoop to find hydrogen gas leaks on our generators and associated piping.

Good tip, David. Thanx for posting. Tanks leaks can be incredibly frustrating.

Tank has been reinstalled with fuel in it and all appears to be back to normal. Full pump has been run circulating fuel via purge valve to left tank, no leaks anywhere so wing-fuselage fairing is also reinstalled. It is necessary to disconnect and slide outboard the aileron push tube to get at the Z bracket bolts so removing and reinstalling the tank is a lot of work - all for lack of a #30 hole in a vent cover .

This is turning into an annual condition inspection which is due so I removed and checked the fuel filter while in that area of the cabin this morning - nary a spec found in it. The AFP filter is quite large, I feel good about having it, it would take a lot of stuff to jam it up.

The engine compartment has been checked over and slowly moving aft checking and lubing flight control system. Amazing how much dirt and debris accumulates on fuselage floor, good time to vacuum it while panels removed.

Hope to have this thing flying by weeks end. Along with getting the medical certificate renewed last week, also got a quote on insurance for coming year starting in June, it is down $403 from a year ago at a bit over $1400, what a deal!!