Sloshing sealer

[raytoews]

My friend Bill has an Avid with the integral fiberglass fuel tanks.one of them developed a leak after four yrs, we removed the wing, peeled off the fabric under the tank, cleaned prepped and patched. Now four months later it is leaking again.
I am suggesting sloshing sealer, I've never used it, read about it, so of course I'm an expert. Not.

Any experts out there who have used it and success?

Thanks

Ray

[L16 Pilot]

I'm hardly an expert never having sloshed tanks but everything I've read concerning it seems to lead to the possibility of some of the sloshing material getting loose and plugging fuel lines and strainers. I had a fuel tank that was pin holed on my Chief but replaced the bottom of the tank (aluminum) rather than taking a chance with sloshing. I do know it has been used on old cars, tractors, etc. but they don't fly .

[Michael Huffman]

There was a sloshing sealer (PR-1005L MIL-S-4383) that was popular back in the 1960s and 1970s before the advent of 100LL fuel--it is essentially a rubber compound dissolved in MEK. In those days, aviation fuels (80/87 and 100/130) were made using straight-chain ("aliphatic") hydrocarbon stocks and it worked well. I used it routinely back then.

However, modern fuels have more "aromatic" content (especially auto fuel)--molecules that have more of a solvent action (think benzene, toluene, etc) than straight-chain stocks. In addition, most auto fuels also contain ethanol. So, the experience was that the fuels began to dissolve the PR-1005L; there were stories of people opening up fuel tanks to find the PR-1005L hanging in long strings from the top to the bottom of fuel tanks--definitely a bad thing. In fact, in 2009 a Stewart P-51 crashed in Florida due to sloshing sealer clogging the fuel tank outlet; the pilot was killed.


I don't know anybody who still uses PR-1005L for airplanes. The manufacturer still offers it for sale for a few race car users. I notice that Aircraft Spruce has an old-formulation sloshing sealer (Randolph #802), but there is a prominent warning against using it with any fuel containing alcohol. They also have a new alcohol-resistant sloshing sealer (Randolph #912); however, in the situations I've seen with fiberglass tanks, by the time the tank begins to leak, the entire tank bottom is soft and mushy--a situation sloshing sealer will not fix.

Most everyone has moved from fiberglass tanks to either aluminum or molded polyethylene/polypropylene. You can probably still buy molded tanks specifically for the Avid series.

[martymayes]

Somebody had a similar problem with a similar plane. Maybe you can contact him and see how he solved the issue?

http://eaaforums.org/showthread.php?...lass-fuel-tank

[Mike M]

I built an Avid. Lots of folks told me about their problems of pinholes in the tanks so I decided to slosh them before installation, since it would be a bit tough to rotate the tanks in all directions once they were installed on the flying aircraft. Used alcohol-proof sealer, just in case I mistakenly got fuel containing alcohol. It did not adhere well to the completely fresh, unused, never contaminated with fuel or two-stroke oil, factory-supplied tanks. I discovered this after a couple years of flying. On old Route 66 just east of Joseph City Arizona after a precautionary landing due to slow steady power output decrease. The fuel filter was clogged. Huge sheets of the stuff came loose. And broke into little flakes. Removal was not fun. on the bright side, I never had a fuel leak in ten years. Your mileage may vary.

[cub builder]

I have successfully sloshed new, uncontaminated fuel tanks constructed with Saf-T-Poxy using the inexpensive alcohol resistant sloshing compound sold by Aircraft Spruce (Bill Hirsch Sealer). 20 years and 1100+ flight hours later, there is no sign of failure in any of my tanks, no flaking, no peeling. However, based on the experience related by Mike M, it sounds like the compound does not adhere well with the type of glass or polyethylene used in the Avid tanks. If I was going to open the wing to do tank repairs, I'd probably plan to build new tanks.

-Cub Builder

[Rick Clarke]

Bought a Luscombe that had one tank sloshed due to corrosion.....did not know that. After a year of active flying the "slosh" moved into the carb, etc. Tank was trashed.........Looked like a slosh jungle inside. I sure wouldn't do that if I had the choice.

[George Sychrovsky]

It is unlikely sloshing old tank will seal it , One of our local guys had the same problem , I ended up cutting the top of the tanks off and building new tanks inside the old ones.

[raytoews]

It is unlikely sloshing old tank will seal it , One of our local guys had the same problem , I ended up cutting the top of the tanks off and building new tanks inside the old ones.

How did you get it to seal. We put a patch of fiberglass on one spot it was leaking. It continued to leak. Did you reglass the inside?

[George Sychrovsky]

I built new tanks and put them inside the old ones , That way I didn't have to rip the wings apart by removing the old ones.