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 :cool:.

[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?820-Sealing-leaking-fiberglass-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.66216622

[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.66216622
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.

66326633

[raytoews]

Price for you to build us a tank??
Why did the right tank leak and not the left?
We put a fiberglass patch where it seemed to be leaking, didnt fix it.
Then we got some sealer that was guaranteed to fix it, painted it all over the bottom, quess what?
Are you building with Epoxy resin and closed cell?

[George Sychrovsky]

I did not say the right tank leak and not the left, I built both of them.
I use vinylester resin
and closed cell? - I don't understand what you are asking here
I can build a tank like this for us $1,400.00 a piece or $2,400.00 a pair

[raytoews]

I did not say the right tank leak and not the left, I built both of them.
I use vinylester resin
and closed cell? - I don't understand what you are asking here
I can build a tank like this for us $1,400.00 a piece or $2,400.00 a pair


I am curious, on our aircraft only one tank leaked. The other is fine. Left full it takes a couple of days to start leaking. What did they do different?
We thought we had found the leaking area and put a fiberglass patch over it. No luck. Then an aircraft mechanic suggested a product like rubber, (smelled like PRC we used to put windshields in F104s) painted on the bottom. Guaranteed it would work. Not so much!

Now we are a little stumped.

Your solution looks good but heavy and expensive.

The reviews on sloshing sealer are mixed??

Thanks

[Rick Clarke]

A previous owner sloshed one of my Luscombe's wing tanks. The sealant started coming off the tank. The carb did not like pieces of sealer trying to move through the system at takeoff power Tank replaced. Sloshing seems a temporary "solution." No problem if you're selling the plane.

[George Sychrovsky]

Your solution looks good but heavy and expensive.



Thanks

Yes the leaking tanks are a lot cheaper

[Bill Greenwood]

There was a problem with the integral wing tanks leaking in Mooneys as they got older. My a i sealed mine in the (77 M20 J) and it worked fine. I didnt do the work or see it first hand, but the sloshing sealer, I recall is a black tarry stuff, came in a quart can or so. The key he said was to remove ALL the old sealer and residue from the seam before using the new, I think he used plastic scraper, maybe even a credit card so as not to scratch the metal. I dont know how this would work with fiberglass tanks, the Mooney ones are metal, aluminum.

[cub builder]

A previous owner sloshed one of my Luscombe's wing tanks. The sealant started coming off the tank. The carb did not like pieces of sealer trying to move through the system at takeoff power Tank replaced. Sloshing seems a temporary "solution." No problem if you're selling the plane.

Tanks really have to be properly cleaned and prepped in order for the slosh compound to bond. (See the process on the KBS Slosh compound web site) Aluminum tanks in particular are smooth enough that the slosh compound tends to peel in the middle of the panels where there really isn't anything to give the compound any "bite" to the surface. Just putting a slosh in the tank is akin to painting aluminum without etching. It just doesn't hold. The KBS compound uses an acid etch as part of their process.

FWIW, I sloshed the composite tanks on one of my planes 22 years ago. I have never seen any peeling, flakes or fragments. It was sloshed with the Hirsch compound sold by Aircraft Spruce. The composite tanks on my other plane were recently coated internally using the KBS process, which is also recommended by Arion for the composite tanks in their Lightning Aircraft.

[Frank Giger]

I have nothing substantive to add to the thread, other than to remark that I laughed outright at this:


Yes the leaking tanks are a lot cheaper

It's rare that I actually laugh when reading something in a tech forum.

[DaleB]

It's rare that I actually laugh when reading something in a tech forum.
I do it all the time. Have you SEEN some of the advice people get?