Another tank sloshing thread

[Captdill]

I successfully repaired my right wing tank (aluminum) some years back externally. It was leaking at the tank seam when I got it in 2004, right there below the gas gauge. I cleaned the surface, covered it with tank repair putty (two-part looks like a tootsie roll) and then covered that with a layer of fiberglass and two-part resin for gas tank repair. BTW, while leaking, with wings folded, the gas ran down the wing to the second flap hinge and into the flaperon, dissolving the Styrofoam core within. I got it that way.

I have read most of the threads about sloshing tanks. Curiously, they gravitate towards Kreem as the preferred slosh, even though it is the only one that is known to flake and peel away. (Honorable mentions are Por 15, Caswell, and the plastic replacement tank from AirDale.) Mine has aluminum tanks that were coated with Kreem. When I noticed that failing about four years ago I sloshed it with MEK to remove most of it. More recently I noticed my left tank seeping, but only with a full tank and I conclude that the source is at the top of the tank. I was going to rip into the fabric to do an external repair, but have decided first to re-slosh the inside. Why should I use Kreem?

[Xengineguy]

Hi Jeff, my vote would be a product called Red Coat, I have had very good results with it . It is mek based,remains pliable (unlike cream)
Your biggest problem is getting ALL the cream out! Some people say mek dissolves cream, I never got that lucky! In the last 20 years I have used red coat on maybe 400 /500 tanks. :)

[Captdill]

Thanks, their website says available at O'Reilly's. Your success means a lot. I really want to avoid future problems and the track record of Kreem leaves me uneasy. BTW, another name that came up was Hirsch. Also BTW, the two-part Caswell website says something like "most failures are because of improper mixing". Maybe so. I gather Red Kote is not two-part.

[Xengineguy]

You are correct Red Coat is not two part. Clean up and thinning done with MEK.
Normally you won't need to thin it. Make sure the tank is completely dry before coating. Cream = PITA. Good luck. Mike:o

[n85ae]

Red Kote says specifically in their spec sheet - "Do not use Red-Kote on
fiber-glass or any plastic".

http://www.damonq.com/techsheets/red-kote.pdf

[Xengineguy]

I would bet they are worried about the MEK softening the resin in the glass tanks. Don't know. Test it, and see if it works for your application. Mike

[SkyPirate]

I decided a while ago that if I ever have problems with my fuel tanks I am going to make new tanks out of aluminum,..but rather then weld the seams..I will use a fuel tank seam sealer and roll the seams,..a pliable sealer,..doing this should eliminate any vibration/torque induced cracks that can occur at welded seams

[Olle1975]

Why do you seal a aluminium tank?

I have the 6 gal aluminium wingtanks in a Kitfox III, there is nothing slosh inside and it works.

Olaf

[Captdill]

I am sealing mine because it is leaking. I will probably also slosh the right tank which is not leaking. This is not just to match. A few years back I did what I could to remove the cracked Kreem with wings installed, surely still some left. I think the new slosh will contain any of the old stuff that I cannot get out, it makes sense to do it while I am all tooled up.

[Olle1975]

OK, I have rinsed my tanks with aceton to remove the Kreem. The tanks are leakproof, I hope for a long time....

Olaf

[Captdill]

Hi Jeff, my vote would be a product called Red Coat, I have had very good results with it . It is mek based,remains pliable (unlike cream)
Your biggest problem is getting ALL the cream out! Some people say mek dissolves cream, I never got that lucky! In the last 20 years I have used red coat on maybe 400 /500 tanks. :)


Mike, or anyone, Has anyone used Red Coat with ethanol gas? I am thinking about returning two cans to O'Reillys because the label warns do not use methanol. It says some have experienced the methanol dissolving the red dye and sending it through the engine. Should I care if red dye goes through my engine? I usually don't use gas with ethanol, but Rotax allows 10% and I have in the past.

[Flybyjim]

I assume this is done to the old style tanks not the tanks with the SS7?

[Captdill]

Mine are aluminum, from the early 1990s. I suspect my leak was through the gasket for the fuel gauge, which is a float geared to a dial reader. But previous slosh had started flaking.

I called Red-Kote support to answer my own question. They said Ethanol is OK, Methanol is not OK. Auto racers sometimes use Methanol.

[rdooley79]

This worked well in mine and it'll work with fiberglass. Also steel, aluminum and pretty much everything. Aircraft Spruce sells it but you can get a 3-part kit from Bill Hersch's web site, same exact stuff, that has a cleaner and an etcher.
I personally think the kit with the 3 part process is the way to go. You'll need one quart per tank, so two kits for both wings.

http://www.aircraftspruce.com/catalog/appages/gastanksealer.php?clickkey=11756

http://www.hirschauto.com/prodinfo.asp?number=ARK-01

Word of advice is to go to your local auto store and get a spare gas cap. They're like $5, no biggie. You'll need it no matter what. Plug up the breather hole in the cap. JB weld worked great for me and resisted the etcher nicely. Use it to cap off the tank for this entire process, save your nice cap and don't even think that you can seal it any other way. I tried and had to do a little paint touch up... ya it wasn't cool. $5 cap at autozone is the way to go.
Go to your local home depot and get a 6" length of cheap threaded pipe that will fit your sump drain fitting, get a cap for the pipe as well. It works great to drain all the liquid out cleanly in to a bucket. cap the pipe while sloshing of course.

Use some throw away fuel line, the blue-clear poly type is nice. Use some scrap bolts to thread in to the fuel line to stop them up. They seal great when a little larger than the ID of the hose.

Get one buddy to help you pull the wing off but definitely two to put it back on. hahaha.

You'll need a good buddy to help you slosh the wing around. You'll find it gets acquard and heavy but just take your time and be sure to get the top outboard towards the wingtip side. It's the hardest to reach. You'll have multiple sloshings with the 3 step method.

Find a small fan that you can rest on the gas cap to help it breath, pulling air through all the fittings. Expect to be able to do one step per day, roughly.

For the sealer, after you're done sloshing every nook and cranney. Tilt it all the way up, even the cas cap. Get every surface at least a couple times until there is nothing left inside to really move around. The entire quart should cover the tank evenly and have nothing left over when done. Let it tack up a little then take an air compressor with a blower nozzle and blow back through all your fuel fittings and sump in the tank, directly blowing any white slosh back in to the tank. I'd check it in an hour after that and blow them out again. This let the cream set and I knew the fuel fittings weren't covered up. With mine, about 40lbs of pressure in my tiny pancake compressor was enough to blow them out nicely. No residue or anything, worked great.

While you're at it, I would replace your fuel filters and get a new sump drain valve. If you have a brand new sump drain then that's fine, they do leak at the most inopportune time and the seals get chewed up after a while, plus they're like $18 from spruce as well. Definitely get new filters and watch them for the first few tanks. It's only prudent. I haven't seen anything in mine yet but it's always good to do anyways. Easy little stuff that'll make you feel good about your fuel system.

Put the wings back on and hook everything back up. Dump some ethanol pump gas in and fire it up. Go fly!

Just my $0.02. Others probably have had great success with their methods. This is the only one I found that was reported to work very well with Fiberglass. I've only got about 20 hours on mine since the slosh but others have used this same system on here and none have reported any problems. Looking around on the internet this Bill Hirsch system has been used with much success for other fiberglass tanks. Your results may vary and they do say it's not for "aircraft" use but is great for everything else. go figure, it's a liability thing. You know the deal with Experimental anyways.

[Captdill]

Working alone. Made a rotisserie using tow-strap material. Was able to leave the struts attached; 15+ foot ceiling helped. Previous note referenced a $5 gas cap to seal with wing inverted, but I was already looking for something else, since my experience suggests that a regular gas cap leaks even with vent hole plugged. Besides, I had already found my solution, which came from a bicycle horn. It had been plugged by mud-wasps anyway, so I cut it at the largest diameter and found an absolute seal when clamped. I could invert the wing no leaks with Acetone and remove the clamp to drain the tank with a huge flush that carried much Kreme with it. I graduated to sloshing MEK then Red Kote.

Before I forget, that Tygon vent line in the picture was no match for the MEK, so don't make the mistake of leaving it there.

The picture shows a hole used in my tank for the fuel gauge, which allows a good vantage for viewing progress, along with the gas-cap hole. There is high risk of paint damage with all three chemicals and eventually it becomes a risk vs. benefit equation trying to get it all out. When I made the decision to go ahead with the Red Kote, it was with the conclusion that it would encapsulate any remaining loose Kreme and keep it out of my fuel system.

I like the previous suggestion to replace the fuel drain with a threaded pipe and cap, my solution was a valve that was in my junk box.

Hope this helps. I rely on the pontifications of those before me when addressing maintenance issues, often dredging up good info from years ago using the search feature.