Cleaning 7AC Tank

[k2bords]

Hi all - I was able to find an old gas tank for my project, but the tank has been sitting empty for quite some time looks like. It's corroded, not badly, but it's definitely not fresh inside. I was wondering if anyone has any experience cleaning these things up. Is there a slosh I can do and just seal up all the bad stuff? I figure in the worst case I can cut a hole in it, blast it and then have it welded shut. Any suggestions?

[joea]

Have not heard good things about the various sloshing compounds. Most people I have heard take a length of chain and some carb cleaner that is approved for use on aluminum and place the two inside the tank and agitate as needed until clean.

Joe

[CptKelly]

Years and years ago, I used to own a Clipped wing Cub. Its fuel tank had several very small pin holes. I soldered what I could, and then sloshed it with Randolph's Sloshing Compound. I flew that cub for another 3 years, and never had a minutes worth of trouble with it. It worked well for me.

Mike

[joea]

Mike,

Problem is that the fuel "years and years" ago did not have the additives that it does these days.

Ethanol is evidently VERY corrosive to lots of stuff, sloshing compounds among them. Would be very careful with things like this these days...

Joe

[CptKelly]

Joe,
I reckon the best thing to do is to call Randolph, and just ask them if their compound is ok'd for use with auto fuel that contains ethanol. By the way, ethanol is only slightly corrosive. Now, methanol is completely another story.

Mike

[Nathan K. Hammond]

Matt,
You'll be surprised what house-hold cleaners can do. "Greased Lightning" is a tamed down version of 'White Lightning' used by truckers to clean all their aluminum; it's basically Muriatic Acid. This will do wonders for brightening the aluminum in the tank and at the same time, will remove any bits of corrosion. I used a gallon of "Greased Lightning" to clean a 150gal aluminum tank that was converted into a portable fuel dolly; and it did wonders. Pour a little in, slosh and shake, dump and repeat. Joe's suggestion of adding a bit of chain is pretty slick; but a couple things to remember that tank is fairly light and fragile. Banging chain could damage a seam and create a leak. Aluminum wool or a handful of nuts and bolts may be a little easier on the tank.

Cutting open the tank and re-welding is a little excessive.

From my experience, sloshing compounds for sealing are bad news. We used some on the Cub fuel tank when trying to seal up little weeping pin holes. It worked and fixed the problem, but about 5 years later the compound started to breakdown and release into the fuel tank and eventually through the fuel system. It looked like snot; long string globs, which travelled down the fuel lines (partially blocking them), collected in the fuel strainer and became a Major headache! FWIW.

Good luck.

nkh

[Captgrumps]

Sloshing compounds with todays fuel is a crap shoot..

Doug

[Captgrumps]

Sloshing compounds with todays fuel is a crap shoot..

Doug

[flyingfool]

I have to remove the aux tank in my chief beause somewhere in the past someone used a sloshing material. I suspect this was many, many years ago. The previous owner used autofuel. And I think that cut the old sloshing material. That or having the tank sit bone dry forl years never used may have dried the sloshing material out and now it is falling off!

So now I have to find a way to remove it and clean it out. SO my recommendation is not to use any sort of sloshing material of any kind. You're only asking for trouble (or the next owner) latter.

I heard Acetone will work to clean this stuff out. I'm not sure about bare aluminum. But is is pretty harsh stuff so I wouldn't doubt that it would work.

The size of chain to put into the tank is aluminum chain about the size that you would hang a shop florescent light up with. You know those cheap $20 florescents that you can get. You can probably get a foot or so length from your local hardware store or Home Depot. Use your judgement as to what size/weight of chain would likely not cause damage to the tank.

[gusc]

I know theChamp oil tank is Al but I thought the fuel tank was lead lined steel??

[joea]

Gus,

Stock was aluminum with no lining. Who knows whats in many of our planes by now.

Joe A

[Robert Henley]

Hi all - I was able to find an old gas tank for my project, but the tank has been sitting empty for quite some time looks like. It's corroded, not badly, but it's definitely not fresh inside. I was wondering if anyone has any experience cleaning these things up. Is there a slosh I can do and just seal up all the bad stuff? I figure in the worst case I can cut a hole in it, blast it and then have it welded shut. Any suggestions?

I sent my Champ fuel tank to Conrex, Inc. near Phoenix Skyharbor airport. They are an approved repair shop. They cleaned my tank and pressure tested it. No welding needed however there was a slight seep at the filler neck. They wouldn't weld that because the filler neck is steel. They send the tank out for cleaning. Mine was very dirty and gummy inside. It looks great now.

Conrex is at 602-275-9585. It wasn't cheap but I feel it was worth it.

Regards

Robert

[k2bords]

Well I tried the grease lightning with some chain and it did alright. Still needs a little more tossin' around but I think it will get there (good enough anyway). I looked on the label and was surprised when it specifically said not to use it on aluminum. Know anything about that Nathan? I made sure to rinse very well after I read that. What about using alumiprep?

Matt

[Nathan K. Hammond]

I was told it can make some nasty fumes with aluminum. What they are, I don't know, but it didn't hurt much when I breathed them in.. them in.. them in..
I see no signs of damage in our tank, 3 years later.

Alumniprep would be fine, and might pick up the bits left by the other cleaners.

nkh