Cleaning gas tank before welding?

jphilipson

Registered
So I need to weld a bung onto my gas tank for the aux fuel system I am working on. From what I understand, it should be cleaned thoroughly of any gas residue before welding with soapy water a few times to avoid gas vapors. My question is, having never done this on a m/c tank, will cleaning with water pose any problems? I assume the tanks on modern bikes like the Busa are galvanized or coated in another manner to prevent rust etc.

So soapy water, rinse and repeat a yay or nay?
 
I would make sure all the gas is drained out of it, let is set for a few days outside for anything left to evaporate out of it. not sure how I would do it after that.
 
Leave the tank full of water too, would be my suggestion, I have watched a friend weld a tank on his jeep this way, while I stood at the end of the driveway with a fire extinguisher!
Maybe bigbaddodge will chime in???
 
I would make sure all the gas is drained out of it, let is set for a few days outside for anything left to evaporate out of it. not sure how I would do it after that.

It takes ages for the gas residue to dissipate enough to weld on tanks that have been emptied. I know they need to be cleaned - just curious if the washing with soapy water method typically used was safe on the Busa tank if anyone has done it.
 
Weld I can weld enough to get myself in lots of trouble. The best way to weld a gas tank is in an inert sealed tank.

However, and I do not recommend this, but one year at Bonneville my tank cracked and was spraying me down with fuel at speed. I wasn't going home as I had records to break. Took the tank off and drained all of the gas, opened up anything and everything that would allow air to get into the tank and let it sit in the sun for a bit. Time was running out, so out comes to the propane torch, gloves and sun glasses and a long extended arm, got it as close to the filler as possible and it lit off.........gave it a few minutes and did it again, lit off again.......we welded, and ran the bike the next day.
 
I would wash it with soap/water, leave it in the sun for a couple of days, leave water in it while I welded, rinse it with clean water again...a couple of times, let it dry, rinse it with gas a couple of times then re-coat it.....but that's just me.:beerchug:
 
Rinse with soapy water and weld it with water in it. Let it dry, and rinse it with a little gas making sure you coat everything. Should be good :whistle:
 
you have to flood the tank with inert gas. while its full wield the bung on. then drill the hole after. safest way to do it
 
I have repaired many gas tanks from cars, tractors and heavy equipment. I have always washed them out at least 3 times with a detergent such as Castrol Superclean, rinsed them out, usually by running water through the tank with a hose set at a low flow rate and then left them filled with water. I filled them with the maximum amount of water leaving a very small amount of air in the tank. I positioned the tank so the pocket of air would be right where I was brazing the tank.

Either fill the tank with water or purge it with an inert gas (CO2, argon, helium) BUT DO NOT rely on just washing and rinsing the tank. Do NOT underestimate the danger presented by a tank with even a small volume of gas fumes.
 
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