Alum. tank cleaning

[Joel H.]

I removed my tank from the boat and successfully siphoned, then rinsed, out 30+ yrs of sediment, using a strong detergent and lots of water. I then dryed it thoroughly by forcing air through it for two days.
But on close inspection through the access holes I see a layer of varnish scale on the sides from about a quarter tank level on up. Obviously it sat a while at one point. Anyway I have all winter to get this perfect and I'm wondering what home remedy there is to eat that varnish off. I don't want to use a volatile solvent because I don't want to re-arm the bomb, so to speak. I'm thinking Muriatic acid, or something similar, but of course I don't want to compromise the aluminum.
If anyone has a suggestion I would appreciate the input.
Thanks in advance,
Joel H.

[JOHN COOKSON]

Carburetor cleaner or lacquer thinner. Both are volatile however. Do some research before using strong acids or bases around aluminum*. Maybe pressure washing would work? Maybe tapping on the outside of the tank with a hammer would loosen the crud?

TRUE GRIT

* Edit: Don't use strong acids and bases around aluminum. You won't have much aluminum (metal) left!

[Mo]

I agree with John. Lacquer thinner is probably the best option...dump a gallon in it and slosh it around. Safety first, no ignition sources around and follow safety instructions. An appropriate mask would be a good idea as well. If you have an opening large enough might want to try and get a toilet brush or something similar and give 'er.

I'd keep acid away from aluminum. Good luck with it.

[edwardc]

Well, since one of the drawbacks of E10 fuel is that the alcohol supposedly dissolves varnish out of your fuel system to be deposited elsewhere, why not try 100% alcohol? It's non-explosive. 100% ethyl alcohol is pricy to get, but either 100% iso-propyl alcohol, or denatured (ie - stove fuel) alcohol, is easy and inexpensive to get, and may do the trick.

Maybe one of the more chem literate members could elaborate.

[msmith10]

I did this a few years ago with carb cleaner- NAPA has it by the gallon.

[dvd]

If the tank is compromised why take a chance putting it back in. At least look into a new tank. I bought a plastic Moeller tank and it works great. cost was about $150.00. Go to the Moeller website and at least see if they have something that will fit right in no hassle or fuss. They all seem to come with fuel guage sending units already installed.

Might save you some time and trouble in the long run.

dvd

[JOHN COOKSON]

Well, since one of the drawbacks of E10 fuel is that the alcohol supposedly dissolves varnish out of your fuel system to be deposited elsewhere, why not try 100% alcohol? It's non-explosive. 100% ethyl alcohol is pricy to get, but either 100% iso-propyl alcohol, or denatured (ie - stove fuel) alcohol, is easy and inexpensive to get, and may do the trick.

Maybe one of the more chem literate members could elaborate.

Ethyl alcohol is both flammable and explosive. As we know it is used in place of gasoline. 100% alcohol has a lot of pop because there is less water in it.
Stove alcohol is methyl alcohol (1 carbon) which is even more treacherous.

TRUE GRIT

[ndutton]

DVD, you da man!

Solid advice, thumbs up vote from me.

[Joel H.]

Thanks for all the feedback guys. I'm going to think about my options for a while. Any other input is greatly appreciated.
Joel H.

[Marian Claire]

I tried solvents and pressure washing to clean my SS tank. Ended up having to create an access port and scrub the crud out with a Brillo pad. Replacing with a new plastic tank would have been easier and safer. But due to the unusual shape and my desire to retain the large, 35 gal, capacity I choose to clean the old tank.
Warning: Creating an access can be hazardous.
This thread may help. http://www.moyermarine.com/forums/sh...highlight=tank
Be safe. Dan S/v Marian Claire

[Mo]

plastic tank...good point guys.

Never considered the plastic tank. By the time you gear up for safety, cleaner, access you will likely be ahead of the game if you purchased a plastic tank.

[Whippet]

Joel H

Have been thinking of removing alum tank as well. I have 1981 C&C27 and never sure of longevity of alum tank. Wouldn't be anxious to have it fail 3 hours from marina. What is your boat and how hard to remove? I have heard C&C is tight squeeze to remove.

a few questions for forum:
1) any opinions about expected life of alum tank before failure?
2) Assume Moeller replacement size just has to be in ballpark, not exact, and attach points have to be modified. Did you re-use prior fuel sender or replace?

I also heard of marine supply (HMP in Toronto) that will take current tank and coat inside with plastic. might be another path

[dvd]

Whip

The Moeller tanks all seem to come with the fuel sending stuff already installed. The only thing you need to get is the guage. Not sure if any guage would work.

[Mo]

Whippet,
Is your tank in the stb lazarette...cylindrical looking thing. If so it should be easy to come out. I've fixed up a few 27's this summer and the tank was right there. Shouldn't be much to it to get it out and replace with plastic if that is what you want to do.

[rhody jim]

just cleaned out my aluminum tank by the Moyer suggested method....2gallons of denatured alcohol and MANY ( more than 20) flushes thru the tank and filtering with coffee filters in between. no real expense involved as remaining alcohol will be used in Origo stove. Most of debris coming out of tank is aluminum oxide.... pressure test was positive and no leaks exist at this time.....only question now is whether or not catalina's 5 hole pattern in sender in 1980 is the same as todays SAE pattern 5 hole replacements.