Gas Tank Coating Removal

[billpedalino]

When I received the gas tanks for my '47 FL they were internally coated with a red (supposedly) protective coating. I hate this stuff, but I decided to leave it on and hope for the best (yes, I was lazy). Now, apparently the pass-over line gets clogged and the bike runs on the left tank only. I haven't disassembled the tanks yet nad he carburetor strainer is clean, but I'm fairly certain that the coating is flaking off and causing the clog.

Does anyone know a safe and effective way to remove this internal coating?

Thanks...

[T. Cotten]

Bill!

I would try blowing out the line first, before going to a lot of trouble. It might be something else.
A turkey baster with a vinyl tubing extention worked for me. (It was a mayfly exoskeleton.)

....Cotten

[17thairborne]

There are hundreds of posts on various sites discussing this issue. I had the same problem with my 42WLA. Constant clogging of filters and carb jests as the crap flaked of the interior of the tank. I did not, nor do I intend on re-lining.

The options I found were:

1. Cut the tank, blast and re weld. You just can't blast inside all the nooks and crannies with a conventional blast gun unless you cut the tank. I'd hate to destroy an original tank by cutting, but this will be the best way to clean 100%. I did not chose this option.
2. Insert some abrasives (rocks, nuts, bolts) and tumble for a while knocking off all the old crud. (will damage the areas inside where rust might have begun to eat away at the metal. might also pierce the tanks and make small dents) I don't know why people choose this option for an old tank.
3. Hot tank like a radiator. I wanted to do this, but ALL of the radiator shops in my town of 50,000 have quit dipping tanks in the old style due to environmental issues. (This might be the best way, but I was not able to try it)
4. Use a very caustic material like MEK, to eat away at the lining. This is the method I used and although it is not environmentally friendly and the fumes can be deadly if the procedures are not followed, this will literally eat all the crud out of the tank. I let mine sit and fume for about 5 days turning to make sure the MEK could work on all surfaces. I followed up with a rust remover after wards.

Using option 4 I cleaned out my tank about 99%. I will let the NOS filter catch the rest. I ran the bike for several miles with a clear line and clear in-line filter just to see if anything was left. After about 80 miles, the clear in-line filter had no more crud. Now the problem is to keep the tank from rusting. Just keep it full and use a water remover like Stabil or sea foam. I also use AV gas in stead of auto gas.

Others with more experience should weigh in on my comments. I have only done my one tank and read 100s of post about the subject, evaluating the merits and detractors based on all the comments and images posted.

[Travis]

I had the same problem with a tank coated with tank "Cream" of the 80's and 90's. Never had gas in it for 20 years. (plenty of time to cure) First tank full of gas and the stuff started coming off and it was a restored bike with an excellent paint job so I was really in a fix !! I did find a place in Calif that could dip it to strip the inside WITHOUT damaging the paint !! And it did work. BUT it cost over $350. to do it. If you want to spend this kind of money the place was called "Rusteco" I don't know if they still offer this service but it is worth checking out.
best of luck Man, Travis The Nimbus Nut

[billpedalino]

Thanks to all for the above options.

Cotton: I do plan to disassemble the fuel system and take a close look at, and evaluate the tank interiors before exercising my usual M.O. of slamming a mouse with a bazooka.

17thairborne: I used to work in the bridge painting industry and have a full 5-gallon pail of MEK, but I'm reluctant to use it because of the damage that the fumes may cause to the paint, even with the caps installed. While I know that a re-painting is a distinct possibility, I'm certainly trying to avoid it. Were you able to MEK-treat your tanks and not damage the paint?

[Jim]

I used paint remover very carefully poured in with TAPE surrounding the gas cap area. Shook it around with a piece of chain, nuts, bolts to help. It worked... and I did not ruin my paint. I was extremely careful. GOOD LUCK!!

[T. Cotten]

...I also use AV gas in stead of auto gas...

That's great, 17thairborne!

If one only rides in a circle around a friendly airport.

....Cotten

[17thairborne]

Actually Cotten I did that for a living in an A-10. Av gas has lead which helps a lot.

Cheers

[T. Cotten]

Actually Cotten I did that for a living in an A-10. Av gas has lead which helps a lot.

Cheers

So... .. ...

What good does that do the daily rider, for whom it would actually be prohibited?

Some of us like to travel.

...Cotten

[17thairborne]

Cotten,

I'm not a daily rider, and I don't worry about every government regulation. It's use due to the lead content, less tendency to build lacquer makes it better than the crap that is put in most blends today. I can't remember when anyone opened my fuel cap to see what color my blended gas was.

Not much in our live isn't prohibited today.

Anyway, sorry that this thread has gotten off track somewhere.

[17thairborne]

17thairborne: I used to work in the bridge painting industry and have a full 5-gallon pail of MEK, but I'm reluctant to use it because of the damage that the fumes may cause to the paint, even with the caps installed. While I know that a re-painting is a distinct possibility, I'm certainly trying to avoid it. Were you able to MEK-treat your tanks and not damage the paint?

As I was careful to seal off the openings properly, and not spill any, I had no paint damage in the end. I was not too worried about the paint, its not original, just OD spray and I plan on restoring in a few years after I get done riding around the airport in circles.

[harleytoprock]

Bill, I've used both MEK and paint remover with good results. I'm planning to make a neck extension which is basically a 6" long tube that will go on to the tank cap bung and make a tight seal with a gasket. This will prevent dribbling on the paint when pouring out the remover. The extension will also prevent the problem of over flow of remover which happens when the full tank of remover is exposed to temperature changes.( the stuff expands) I would still take all redundant pre-cautions to protect the paint. This neck would be easy to machine for early tanks that have machine thread bungs. It would be trickier on later tanks but it's possible.

[Two lil indians]

Just restoring a 1940 4 and the tanks at some time in their lives had the coating installed. Since I am repainting I had them dipped, and they have been there for 2 weeks trying to soften up the coating. Next up is MEK, which should do the trick. The new tank coatings are comparable with today's gas, so for me a decision will need to be make, weather to recoat.
I think MEK is the answer.

[Steve Swan]

i've removed mek based liners using mek or acetone from a number of (at least 10) tanks including tanks with perfect paint. as mentioned above, the operative words are "be extremely careful." i lay a cover of some sort over the filler opening, such a a hand ball or even tape off the opening with duct tape. and of course, block off fuel tap or other openings. i do the work in an open and ventilated area. i've had no issues with fumes damaging paint. i routinely "roll" the tank so the mek or acetone gets to all the surface area. i use duct tape with palm of my hand over the filler opening to keep any solution from leaking out and not had an accident yet. when i drain out the old gooey solution, i have a copious running water supply at hand and i will drain out the gooey crap through a petcock opening whenever possible. not uncommon to have to repeat the process a 2nd or even a 3rd time. not how i like to spend my time, it's no fun, but i've done it a several times, it can be done.

[Steve Slocombe]

Dear All, MEK is methyl ethyl ketone, an oxygenate, like the stuff they're putting in the modern gas. If it removes tank sealer then I wouldn't use that sealer again. Here in the UK I'm using a new two pack tank sealer that is allegedly proof against this vicious modern gas with all the oxygenates in it. I screwed up the installation once by not having the tanks warm enough, so had to remove the coating. The vendor sold me a 'special solvent' at some cost which was obviously carbon tetrachloride from the smell when it arrived. It worked OK, but I needed a lot more. In a rare flash of inspiration I went to my stock of old Pyrene fire extinguishers and found a couple still had fluid in them. It's banned now of course, as it can generate phosgene with heat, which is never good. Anyway, the dyed red Pyrene carbon tet did the trick over a week or so, with granite chippings and occasional tank shaking helping it along. Yup, I have an economical streak a mile wide, and you're welcome.