Vintage BMW Motorcycle Owners

Hi All

I have taken my tank in for a spot of rust removal (outside only thankfully). The tank restorer has called me and said that he was cleaning the tank internally with acetone and has found that the red lining on the tank has turned gooey.

Is this normal? Should he not use acetone? I would not have thought that the original BMW red coating would go soft like that. Perhaps it hs had a third party lining put on it.

The next question is - Shall we acid dip it to remove the goo and re-line the tank or remove the acetone and see if goes hard again?

I am sure a lot of you are gasping at my treatment of this fine tank.

Any help would be appreciated.

Cheers

Warren

I'm not very good with these kinds of chemicals, but I probably wouldn't have used acetone or things like MEK. Snowbum has a section on cleaning tanks:

http://bmwmotorcycletech.info/fuelmiscl.htm

He has a link there to a product called POR15 which is pretty popular for removing old linings and then relining a tank.

Im no paint xpert but any time the paint has been compromised I would strip in down and start over. Make sure you use gas tank paint that will handle ethanol gas. And i'm sure most do these days. Its OK to say Ill never use ethanal gas but if your out riding and switch to reserve. The gas station is one mile away and all they sell is ethanol base gas it maybe better than walking or pushing.
I used POR 15 gas tank paint ( make different paints) in the gas tank on my 1970 Datsun Roadster 6 yrs ago and still going strong.

Wow, that is a nice Datsun Fairlady.

Thanks neb,
There getting to be like "old BMWs" I bought this Fairlady over 6 yrs ago and even tho the paint being a little ruff and new interior. Its worth 3 times what I paid for it.

I have been thru this myself, more than once. I would definitely NOT use either POR 15 or Kreem, probably the 2 most popular brands.

I found Caswell epoxy liner to be far superior to either of the above, in fact the instructions w/ Caswell include a section on what to do when following up a failed POR 15 or Kreem treatment.

Here's a link:

http://www.caswellplating.com/epoxy-gas ... ealer.html

U don't want to do this twice & no matter what u do w/ the paint on the outside of the tank the inside needs to be sanitary & perfectly sealed !

b

Ive been using POR 15 for about 10 yrs now never a problem. But its all in the preparation same as any paint applied. Only thing that bothers me about the Caswell you can use it on steel, aluminum, plastic etc. Does it do all real well or......

I used it in the engine bay of my 1967 Saab 3 cylinder, 3 carb, 2 stroke.

I,ve only used it on my 6 1/2 tank. It is clear & leaves a thick tough coat. I was impressed by it. I have not used POR 15 & only know it from it's reputation. I have used Kreem....it's a poor joke in my personal opinion. I agree that prep is very important.

Thanks for all your comments. We ended up stripping it back to bare metal and re lining it. The new lining(I don't know what it was) looks great almost like an enamel bath.

New paint job done and it looks great.

Acetone is an extremely potent solvent which is commonly found in nail polish remover and paint thinner. It will melt paint, tank liners etc and if baffles me that this was a surprise to the person doing your tank work.