I've been a welder professionally for 48 years, and to tell you the truth I would turn you down if you brought it to me to weld. Your post brings back memories of a coworker of mine years ago, he tried to weld on a car gas tank, it didn't go very well. He did what he thought would work by filling it with water and letting it sit for a couple of days and draining it and then re filling it with hot water and detergent and then draining and rinsing before he tried welding on it, well it blew up he and it nearly took his thumb off, he was lucky that's all that happened. What you want to do is to dangerous, buy a new tank, your well being is worth more than that tank.

 

Interesting. thanks for sharing your story. I wont be able to buy a tank that fits, the brackets will have to be welded one way or another.

Since I've initially posted my first thread I've been consulting number of locals welders and they have all said it's possible. I will warn them about the fume issue and make sure they've got a life insurance.. (kidding)

 

Thanks sir, is this your thoughts or coming from an actual first hand experience? thanks again.

 

First hand many times over I've been welding cracked and broken harley tanks since the 70's yet to have one go pop. Tanks on my sig bike been welded twice since they were painted.

You doing a tab that's what almost 3 inches from the actual tank? Easy money with a little care.

 

Thank you sir. one last question.

Can battery stay on or disconnected?

 

Dry ice...

 

OP that your concerned is a good thing. You are getting a bunch of ideas and advice that may not be correct but may be comforting to you. I have actually welded and brazed gas tanks, diesel tanks and hydraulic tanks full of fuel. I would actually prefer it that way as less fumes. I have been doing this for over 35yrs and no kabooms. All you need to do is make sure tank can breathe, no sparks near opening, disconnect battery for sure. I'm assuming your mig welding this but it really doesn't matter. The idea of using an inert gas to purge the tank is a good one and if you were to penetrate the tank in any way you would want some type of liquid in there so the left over vapors could not ignite.

 

For safety sakes take the battery off and DO NOT weld any where close to it I saw a car battery blow up one time from cutting torch slag!!!

 

Many years ago, when I was a much younger man, I was helping a buddy fix up an old 1950's vintage pickup truck- gas tank right behind the cab. He was welding (or brazing, not sure which) some sheet metal onto the tank, and if I recall there were several gallons of fuel in the tank. No kabooms or anything, not sure if that was sheer luck or what, but nobody lost any hair or anything.

 

Always pull the battery, just a safety backup. The sealed batteries today don't have the issues the old wet ones did but it's still a good habit to avoid damage.