Tank Rehab.

[balibeemer]

I recently picked up an 1954 BMW R 25/3. Removed the petcock from the tank and about a cupfull of very fine rust fell out. Where I live, there is no such thing as tank treatment so I adopted the following procedure:
1. Remove tank and plug off all outlets( by pass and petcock) except the filler.
2. Half fill the tank with boiling water and soap and swish it around for about 10 minutes.
3. As it was a 12 liter tank, then fill with 10 litres of cold water, and then add 2 liters of phosphoric acid. screw on the filler cap and allow to stand for 24 hrs. The acid reacts with the rust but not bare metal.
4. Drain out the spent acid and neutralise the tank with 8 liters of warm water and 1 cup full of baking soda. Drain
5. spray an entire can of WD 40 into the tank to dewater it. Drain
6. Pour in 2 litres of thinners and swill it around to get rid of the WD 40. Drain. At this time, a lot if pinholes( 6) appeared
7. Mix up half a liter of nitrocellulose epoxy paint and swill it around the tank to cover all surfaces. Drain off the excess.
8. Buy, (or borrow from a very understanding wife) a hairdryer, remove all the plugs/ stoppers etc from the outlets and insert the hairdryer and turn it on full for 4 hours.
9. wait one day and repeat steps 7 & 8

This worked really well. no more leaks, no more rust and no need for extra fuel filters.  

[Ed Miller]

"nitrocellulose epoxy paint" is resistant to fuel and additives?  I'm not familiar with it.

[montmil]

"nitrocellulose ...

Ain't that another way to say "lacquer"? Epoxy lacquer paint? Me know nada 'bout dat stuff neither [smiley=huh.gif]

Monte

[balibeemer]

It must be a peculiarly Indonesian Product! - Made by Nippon Paint

[steve hawkins]

I would have taken down to your local workshop and got them to braise the tank up.

That is what I did with my R65 tank.  

And you would probably find a workshop to do the work more easily that us poor old souls in the 'civilised' world.  And for a lot cheaper.

[Ed Miller]

"And for a lot cheaper. "

And more willing to blow themselves up?  I know, I know.  I used to know how to braise, from high school.  I wonder if I could still do it.

[Barry]

Nitrocellulose paint (I don't know where the epoxy bit comes in) was what cars were painted with many many years ago before the modern 2 pack stuff came along.

Cellulose is still available for use on classic cars and was petrol resistant at least on the outside of the tank.

[balibeemer]

Braise the tank?? Do I do that with onions and gravy? seriously, the tank had just had a paint job and I didn't want to do it again. Also despite the fact that we have some fairly good artisans here, when the BRAZER says " I don't have small enough electrodes for this job" it's time to revert to epoxy paint!

[steve hawkins]

Spelling aside,

Tanks can be repaired properly if you can find and expert to do so.

Epoxy coatings will eventually fail and instead of rust particles you will epoxy particles in your fuel lines.  Hope it lasts a few years though.
 
Oh, and always check a tank properly before you paint it......especially if you are paying someone else to paint it.

Steve H