Tank repair.

[SteveD]

How much does it take to renovate a BMW airhead tank? The answer involves money and time, your money and your time or someone elses time.

DIY is cheapest but unless you have the skills and equipment, it might not be the quality outcome you want. you'll make time though and hopefully not rush it.

1. Cleaning the inside. Vinegar, molasses, acetone, flushing, drying.
2. Stripping a tank outside...paint stripper, metal blasting, dent repair, pinhole repair.
3. Paint preparation. Filling, sanding, primer, sanding, primer, sanding.
4. Paint. Equipment, booth, paint layers, clear coat layers.
5. Final prep: minor blemish repair, polish.
6. You have it home. Now to reline it. Decisions...redkote, por15, kreem, others...

What's that worth d'ya think?

An off the shelf ready to paint tank is http://www.meyer-bikes.de/index.php?pag ... 6111234821 Euro476. Add another 300-500 for paint.

[dirtsurfer]

I tried out the vinegar on my MZ tank and I was pleasantly surprized at the result. There is still some rust in the tank but much less than before. I thought I might leave it at that and insert a filter in the fuel line and see how it goes

I guess the desired end product is an influential factor. Personally, I just want a functioning bike to ride.
$630 AUD plus not less than $60 AUD plus plus paintwork and rondels puts the meyer bikes option out of my consideration.

[SteveD]

Either way is expensive, but if you have the time and patience diy is a valid option. Lots of time, no rushing and an excellent result has got to be possible.

[Chuey]

But, wouldn't you coat the inside before painting the outside?

Chuey

[SteveD]

But, wouldn't you coat the inside before painting the outside?

Chuey

Depends if you need to repair the tank with heat I suppose.
Doing it yourself you could do a solder repair, then line the tank, then paint the outside. The local pro that did mine said to do the liner after the paint as the repair might damage a new liner. Seeing as it's a 3 hour return drive to collect I followed his advice.

[dwerbil]

I used three big bottles of toilet bowl cleaner in the /7 tank to remove rust. It was around 5% hydroflouric acid, same stuff included with the Kreme Koat kit. Left it in a couple days shaking it every now and then. Gave it a good rinse and dry. Maybe has been 15 years now; coating is still good. Think this prep is what KK needs to last.

[Gurstang]

My tank was real bad.
I took the tank for my 75/7 to a local guy to clean and paint the inside. That was a couple years ago.

I put gas in it a couple weeks ago and there are about 2 dozen bubbles forming on the outside. This is with 1 gallon of gas and letting the tank site and hang in different positions.

The guy said he would coat/paint it again, but I am thinking this tank needs to be scrapped. Maybe he can coat it and get it to seal, but I wanted to one day get the tank painted nicely. It seems like it is too far gone to risk spending any more money on it.

What do you think?

[SteveD]

Depending on the size of the holes, POR15 tank liner might fix it from the inside. It's pretty hard stuff.

[Wobbly]

The shop I worked in coated vintage and classic tanks all the time. No matter what the brand of sealer, you should etch away the rust first. Usually a mild acidic solution works best (vinegar to muratic acid) left for hours to days. Then, add your coating to keep the rust from returning. These are best applied before any painting is attempted becasue all of them can be a real mess to work with.

In the US, after trying 4 or 5 brands, we are having the best success with a product called Red-Kote from local auto parts store.

Click to see Red-Kote

[SteveD]

I used red kote. Easy enough to apply.

I di the strip and paint first on the advice of the painter. His concern was any heat or holes drilled to repair anything he thought would need repair would compromise any lining. I'm not convinced it mattered on my tank, but I did it his way.