welding on gas tank?

[hondahaulic]

hey, i have some dents in my 200s metal gas tank. I plan to weld 1/4" bolts to the tank and use a slide hammer that threads onto the bolts to pull the dents out. Then ill grind the spot smooth and use a little bondo before i repaint it so you dont see grinding marks. My question is, how do i make sure all the fumes are out of the tank before i weld on it? Will flushing it with water just a couple times do the trick? Let it set full of water over night? Or would i be completely crazy to weld on the tank? Any help or other dent removeal ideas would be apreciated. thanks in advance

[Mobular]

If those dents are shallow, you'd best just leave them there and bondo it back into shape. Shallow dents tend to pop back in due to the metal being stretched to that shape. You could spend a lot of time heat shrinking it back, but is it really worth it?

[MTS]

Pressure wash the Crap outa it and let it dry...

[hondahaulic]

your probably right about shallow dents being likely to pop back into place, but i have 2 dents that are pretty deep and would take a good amount of bondo to fill in. i want to get them pulled out some so i dont use so much bondo.

[hondahaulic]

hey the pressure washing doesnt sound like too bad of an idea. if i can no longer smell gas fumes, does that mean im safe to weld?

[MTS]

more/less, i would let it dry for a day, But i have welded on them right after washing......LOTSA SOAP AND HOT HOT WATER!!

[traxxasx]

I wouldent suggest doing it this way. You might end up messing it up totaly. There are a couple of tricks to get the dents out. One is to fill the tank with water and put it in the freezer and the expand of the ice will push the dents out. Theres some more. The down fall to undenting dents is there very weak and when they get hit with a little pressure, they give and pop back in.

[Macs]

how i have done mine is i fill the tank with water. Leave it filled. Put the gas cap back on. Gring the area. Use a stud gun with a slide hammer. Then whith a shrinking hammer tap on the crest around the dent to shrink the metal bake into shape. then use poly putty and sand smooth. Make sure you have no high spots and dont let the poly putty get more than a 1/4" deep. Also after the poly putty dries and it is sanded do not let water come in contact with it. The putty will start lifting in time.

[fastleo]

you should fill it full of gas and try to weld on it see what happens lol...........
get back to us on how it works. make sur to have a really stupid person to video tape it for us so we can see how it goes

[Erics350x]

you should fill it full of gas and try to weld on it see what happens lol...........
get back to us on how it works. make sur to have a really stupid person to video tape it for us so we can see how it goes
thats exactly how people used to weld bigger tanks . when filled there isnt any vapors to ignite . not the way i would go but i've seen it done . i just wash mine out with dish soap and water a few times and start welding . just be sure to leave the cap off.

[Dirtcrasher]

If you choose to weld, keep lots of water in that tank. I've known people to rinse the *Edited**Edited**Edited**Edited* outta tanks and still had a small explosion. I would mig weld if ya know whats up or braise it on there. Too much welding heat and you'll burn through, do NOT use an arc welder.

[seadoo650]

Just run a hose from your running car's exhaust to the tank. All carbon monoxide and no oxygen means no BOOM. That's how my buddy pulled the dents in my 350x tank.

[jason 32]

sea do is right- and no rust from the water!
or buy a new plastic one for 125? thats what i plan on doing mine isnt worth a sh!!t

[Bigbore]

You’re going to use a MIG to weld it? If your using a MIG and using a shielding gas like CO2, then you use the MIG gun (with no wire in it) and fill the gas tank with CO2. You don't need to put the cap back on so long as you don't turn the tank over. CO2 is heavier than air and will stay in the tank. If you’re using a MIG welder without a shielding gas, or flux-core wire it won't work. But to do dent or tank repair you shouldn't be using flux-core wire, it leave flux in the weld that will break free later, generally after it painted. If flux-core is all you have access to, take it to someone and let them fix it.

[Dave223]

you should fill it full of gas and try to weld on it see what happens lol...........
get back to us on how it works. make sur to have a really stupid person to video tape it for us so we can see how it goes
Jeez dude, does every post you make have to be this ignorant?

It IS possible to weld on a tank, Ive done it a few times. Be SURE there are no fumes in the tank!
Use lots of soapy water, over and over. .Once that is done I usually tie a small rag to a loooong stick and light it on fire, then pass it around the fill hole.Any fumes remaining in the tank will light and burn off.Then fill it again and weld on it with the tank full of water and NO CAPI learned the hard way and didnt have to pull dents:lol: but i did have to bang the tunnel in a little to get the tank to fit the frame again. :lol: Dave

[corndawg]

You’re going to use a MIG to weld it? If your using a MIG and using a shielding gas like CO2, then you use the MIG gun (with no wire in it) and fill the gas tank with CO2. You don't need to put the cap back on so long as you don't turn the tank over. CO2 is heavier than air and will stay in the tank. If you’re using a MIG welder without a shielding gas, or flux-core wire it won't work. But to do dent or tank repair you shouldn't be using flux-core wire, it leave flux in the weld that will break free later, generally after it painted. If flux-core is all you have access to, take it to someone and let them fix it.
X2...purge it with shielding gas and youll be good to go