Motorcycle Gas Tank Repair - How To Clean First? - Harley Forum

Buzz Kanter · #1 04-16-2009, 12:02 PM

While I had te gas tank off my 101 Indian Scout for another reason I discovered a couple of pin hole leaks at the bottom of the gas tanks. In researching this I found it is not uncommon for these tanks to sperate slightly over time. The solution is to resolder the joints.

I spoke to a local radiator shop that came highly recommended and he said he can do it but I need to thoroughly clean out the tanks first. He said if he can smell gas in them he can't work on them. He suggested washing them with soapy water, rinsing and repeating until the smell is gone.

Any other suggestions on how to get the gas tanks realy clean and odor free?

frisco-rigid · #2 04-16-2009, 01:24 PM

Hey Buzz

Unfortunately either washing out with soapy water or simply filling with water while applying the heat/flame during repair seems to be the Popular method..
However-----
I have welded on my tanks more than a few times by filling them first with the Inert Argon/Co2 gas mix used with my Mig Welding to somewhat dis-place the gas fumes..
And------
I always cover the tank I'm welding with a Heavy leather welding coat..

I also leave all openings Open to allow any ignition, that might occur, a safe and unobstructed exit--- had it happen,, puckers up the ole poop-shoot but no damage or harm done..

I've always heard, and perhaps you have too,, that another apparently safe way is to totally fill up with gas if a guy doesn't want the hassel of filling with water and risking rust cuz the gas does not ignite only the fumes do---- I've heard that but I won't Do that..!!!

Only what I've done is what I have to offer..

Wrightturn · #3 04-16-2009, 04:40 PM

Like Frisco said Argon is the safe solution. I have been able to solder with a large iron rather than a torch or Mig/Tig when the repairs were small. With any kind of sheet metal the least amount of heat is best. When I finally took welding classes about 15yrs ago the instructor told the class to stay away from anything that had ever contained gas or oil. To make his point he played a video of a guy grinding on an old MG TD gastank. The tank had been empty for years but still blew up. I have repaired pin holes around petcocks with JB Weld that have held for years.

unclepsycho · #4 04-16-2009, 10:28 PM

The last tank I welded... I filled with water. Then I applied a flame to the open neck and burned off the fumes. It made a small flame then went out. Then I welded up the hole, drained the water.....Dried it out, letit set overnight to dry completely and then I still had water in the fuel lines for a looooong time. I have no idea where all that water was hiding.. So, once again the argon seems to be the popular choice.

Bigincher · #5 04-16-2009, 11:35 PM

Am I the only guy that uses dry ice? It's the solid form of carbon dioxide, and when it warms up it converts to the gaseous state. When placed into a gas tank, it purges all the oxygen, so ... no oxygen, no flame. No flame, no explosion.
I still wash the tank out a couple times with warm soapy water, then add the dry ice. You can (probably) find dry ice at the local welders supply house, or try Baskin and Robins. Really, no joke. Run you about 3 or 4 bucks for a 2-lb block.
I just never did see getting a good braze with water trying to leak through my work.

unclepsycho · #6 04-16-2009, 11:56 PM

Bigincher
That dry ice idea is a good one, first time i heard of it. Sure makes sence.
I guess That's why we are here, to learn tricks we hadn't run across yet or just plain forgot!