Sealing Gas Tanks

[Rust rider]

Hello CABERS,

While I know this might not classify as a vintage motorcycle in comparison to what others post on this site. I think others might have some insight on some questions about sealing gas tanks. I have a motorcycle gas tank that needs to be sealed as it is weeping along the bottom. Someone has tried to repair it from the outside with some sort of clear sealant. The tank is very clean inside except for the very bottom edges where the leaks are coming from. Upon doing some internet research I am thinking that Caswell and Redkote seem to be good products however the 2 part epoxy Caswell product seems to be better? According to their website it is currently out of stock....

Does anyone have experience with either of these products or have a suggestion on another alternative? I have watched numerous videos but if anyone has any tips on the process I would appreciate the advice.

It is for this bike, 1974 Yamaha DT 125 Enduro with electric start. This is a pic on the day I bought it and now have it torn down for a quick cosmetic and mechanical resto. My father turns 80 years old soon and I want to give it to him for his birthday as I think he will really enjoy the electric start button.

View attachment 1790212

View attachment 1790213

View attachment 1790214

Had success with Caswell. I tried anther brand first and it still leaked. The caswell was used over anther brand and it has held up .One problem I had with my tanks was the plug insert for the fuel petcocks would spin if overtightened. That was on my Harley Jd. At a hundred years of age most tanks are getting to the end of being practical to save.the repro tanks on eBay are usually made in India. They are low priced but not always accurately made. Some of the higher quality builders have waiting list of several years

 

[RM Special]

Thanks to all for sharing your insight on sealing gas tanks.

I ended up using the Redkote product as Caswell was still out of stock when I sealed the tank. It seemed to cover well and did the job following the directions on the label. The preparation process is quite vague on the can but is definitely a key part in getting it coated correctly.

First I put several packages of carpet tacks in the tank and shook it for about 45 minutes total. The tacks loosened up a lot of rust and crust that was not visible from looking through the cap. Next the bottom of the tank was taped off and filled with vinegar and sat for 24 hours. Rinsed with water and drained completely. Added 3 cups of muriatic acid and gently rolled around for 60 - 90 seconds, followed with a water rinse. Finally rinsed tank with acetone to remove any remaining water and sealed the tank. I think the muriatic acid was a key preparation step as it really made the metal appear to be very clean inside.

As several others mentioned I will search for a replacement tank, but hope this one will hold up until I am able to find a replacement.

 

[mikecuda]

I just ordered POR 15.