Drat ! it's leaking

[egp8111]

Errrrr, just when I was bragging on how well my KFIII was doing I discovered the wing tanks were leaking. It's had fuel in it for several months and I've just noticed the leak. I've been very careful not to use any fuel with alcohol in it. Does anyone have any good experiences with any of the sloshing compounds available. The tanks appeared to have been orginially coated with Kreem.

thanks,

EG

[cap01]

When I acquired my kit it was partially completed . the tanks were installed and the wings covered and painted . The tanks were the small ones made in the early 90s . I made a attempt to slosh them with a epoxy tank sealer . Just can't be sure of how complete of coverage you get unless you stick in a borescope . With the baffles and the limited working time of the epoxy, I wasn't sure of the coverage . It really didn't matter to me since once I got her flying I found that the two small tanks just wasnt enough gas . I had never used any alcohol gas and didn't have any leaks but replaced one tank at around 100 hrs and the other at about 250 hrs . I replace them both with 13gal new alcohol resistant tanks .
Never looked back , really happy with the big tanks

[rogerh12]

Any chance you can reach the leak with Pro-Seal?
They have this new injectable type applicator:

http://www.aircraftspruce.com/catalog/graphics/prosealtank.jpg

[egp8111]

I'm thinking maybe cut a section out of the top on the tanks and go in and pro seal entire tank. Then pro seal and rivet an aluminum cover over the hole. Seems like I read about someone doing this. Will pro seal stick to kreem ? I'm open to suggestions.

thanks
EG

[DanB]

EG,
If you are going to go as far as opening the wings then I would look into the roto-molded tanks (plastic) that are made to fit into the existing ones. Someone here might know the web site address, but the idea was cutting out the top of the fiberglass tanks and inserting the plastic tanks. This would be a solution (I believe) to using the alcohol laced fuel, with the only downside I can see being the weight increase. FWIW

Found it... http://www.wingtanks.com/ Has anyone tried these?
Dan

[DesertFox4]

Resloshing the existing tanks is most likely the best approach. Cleaning out the old Kreeme and resealing should solve the problem short of replacing with new Kitfox fiberglass tanks, another option.
8 years ago, right after first flights, I had a leak in one tank and had to slosh it with Randolph's 912 alcohol resistant slosh. I've heard since that this product may not be available anymore. Had several friends there to help remove the offending wing and assist with the rinsing and then sloshing and then reinstall the wing. Not an easy job but doable with good assistants. Solved the problem without opening the wing and replacing a useable tank along with the fabric repair and repainting.

Haven't heard of any successes yet with cutting the tops out of existing tanks and using the drop in roto-molded tanks. Remember that your fuel tanks are a structural component of the wings construction along with forming a large section of the top surface shape of each wing.

[cardinal flier]

9 months ago I removed one wing and sloshed my leaking 13 gal. tank with a compound recommended by John McBean. I think the sloshing fluid was "line-a-tank" John could confirm. So far, no problems. I am currently helping another Kitfox owner patch his wing where he had to remove the covering to determine where his leak was. His leak was adjacent to the fill opening at the top of the tank, on the tip side of the tank. He thinks that possibly force on the tank opening with fuel nozzels, etc. caused the seam to come apart.
Bruce Estes
KF4 with 912ULS, Dynon, IVO IFA
A total blast to fly

[P Morel]

Leaking tanks are very discouraging. I think if I were in your situation, the first thing I'd try is to use Kreem in the tanks. I helped my neighbor Kreem his tanks while still installed in the wings. It was awkward but it worked. You can buy Kreem online. Youtube has many videos to watch.

http://www.youtube.com/watch?v=dT3vUX7vUGs

This may be the cheapest way out initially.

I'm about to Kreem a pair of tanks in my current project. This might work out a little easier since these aren't installed in the wing yet.

Good Luck!

[HighWing]

Resloshing is the thing to do before major surgery. a couple of things to keep in mind. The wing needs to be removed so it can be moved in all positions to cover all slurfaces including inverted. The top fabric should be covered with vinyl sheeting taped in place to protect the finish from spills. All ports should be plugged. The old Kreem should be removed. The typical method is to use a couple of gallons of Acetone, one at a time. For some reason, the acetone rinse produces a gas pressure that needs to be vented a time or two during the rinse to avoid opening a seam. Don't know the recommended procedure now, especially with the newer sealers, but I seem to recall in the old says, the Kreem was reduced about 50% with MEK. I did it once with some rather elaborate support structures, but a friend is essential to help and three or four is even better. Wings get heavy when held by hand for several minutes.
Lowell

[dholly]

Refer to Kitfox Service Bulletin #60 for proper tank preparation.

[HighWing]

This bulletin only covers the tanks produced by Kitfox Aircraft. Tanks produced for the I,II,III,IV,V and 6 are an entirely different material.

[bumsteer]

For what it's worth, Wicks still shows the Randolph alcohol resistent sealer for sale.

[Northof49]

I sloshed a set of tanks last year (March 2011) with Bill Hirsch Gas Tank Sealer from Aircraft Spruce.

They were originally coated with the Kreem, and before sloshing I rinsed them out with fuel. I sloshed them twice; the first slosh I diluted with MEK(aprox 2oz to the quart), the second slosh I did not dilute. I got great coverage in the tank. After the second slosh, I let the tanks sit for about a week before filling with fuel.

They are not installed in the aircraft yet, but they are kept full of fuel (10% ethanol-based) as a test. So far, there is no sign of leaking or delam, as I do tap tests on the tanks.

[dholly]

This bulletin only covers the tanks produced by Kitfox Aircraft. Tanks produced for the I,II,III,IV,V and 6 are an entirely different material.
Lowell,

While SB #60 was written by Kitfox Aircraft for fuel tanks manufactured since November 2007, the proper slosh/rinse procedure recommended for the earlier model 1-6 tanks is also specifically mentioned... and that is my point exactly. One must be certain to prepare their tank(s) properly depending upon whether polyester or vinyl ester resin was used during the tank manufacturing process. Clearly, it was important enough for Kitfox to mention in their SB and, IMHO, worthy of reminder here in the event EG (and others) happened to miss it.

Regards, Doug

[rogerh12]

I am kinda confused. My model 4 was made in about 2001. Do I need to slosh the tanks with something before installing them in teh wings, even though I will be running car gas with no alcohol? I was just going to pressure test the tanks before covering with fabric.

Roger

[Av8r3400]

If you are still at that stage I would definitely advise rincing and sloshing them. It's very surprising that (in KS) you can still get uncontaminated gas. Will you still be able to in the future? That's the great unknown.

[rogerh12]

Yes, the 91 octain BP gas has no alcohol here, and the gas station is near the airport. Also, my ellison injector carb can't used fuels with alcohol either.

Oh, by "slosh", what product do you mean for my particular tanks?

[Esser]

Even if you have ethanol free gas I would still treat the tanks before they go in your wing. It's easier now than later plus you never know when you might not have that supply anymore. Worst case it would help with resale

[HighWing]

Thanks Doug, I did reread the SB and the only reference to the prior to 2007 tanks I could find is - quote:

Tanks that do not have serial numbers etched in the side of the tank were manufactured prior to November 2007. Do not use Acetone in these tanks. They do need to be rinsed thoroughly but rinsing with AVGAS would be the suggested rinse media.

I would suspect that the tanks referred to are the tanks Kitfox Aircraft manufactured before the resin formula change. John has, with good reason, been very reluctant to offer advice on products produced by previous companies. The use of Acetone with regard to the removal of Kreem prior to re-sloshing has been a common practice with no reports of adverse effects.
Lowell

[Dorsal]

I have tanks from around 2000 and rinsed with acetone with great results, would not use tanks without rinsing in this fashion.