motorcycle gas tank welding -advice needed

Aug 13, 2004 23 Replies

I have an old gas tank off of a motorcycle that needs a mounting tab tacked on to it. When I emptied the tank, the gas was real old and smelled like varnish so i flushed the tank with acetone (rusty in there), then rinsed it out with soapy water several times. I dont think it would explode because of the age of the fuel that was in it and it was thoroughly rinsed but i'm not a big fan of blowing my fingers off my body so i'm a bit relunctant to mig this thing. A friend suggested to go outside with the cap off and stick a propane torch in the opening and see if it flashes. If it doesn't, it most likely wont explode. Any comments before I muster up enough nerve to tack this tank.



thanks in advance, walt


Walt,

You have taken some good steps to get rid of most of the fumes. Buy a nice chunk of dry ice and put it in the tank and LIGHTLY cap it. (Saran Wrap the gas cap flange). This will keep the CO2 in the tank but let any pressure escape if necessary.

Done this on car gas tanks and no problems.

I don't thing trying to make it explode by putting a torch in it is a good idea.

Bart D. Hull snipped-for-privacy@inficad.com Tempe, Arizona

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wallster wrote:

all done fellas! I purged the tank with argon from my tig and tacked it with the mig... no boom. thanks, walt

Just fill the tank up with water. Close the cap and vent tube. Turn the tank over so that the area that you are going to weld is located at the small air space left in the tank. I have done this with Oxy-acetylene and occasionally I would get a little burp at the crack or opening I was repairing. There wasn't enough space for any gas residue to have any power. Randy

I did the same thing. I got a hole in my tank from something that got kicked up off the road. I filled the tank with water and as much as I could leaving only a small air pocket. I was going to braze weld it shut with my propane & oxy torches. I had at least 90 % full of water. When I put the torch to it the tank still had enough vapor in it to cause it to give a big burp. Water sprayed me all over from the fill hose. It scared the snot out of me! I wasn't sure if it was the water from the tank, or if I pissed my pants!

Randy Hansen SC Glass Tech Scam Diego, Comi-fornia

hehehehe.... where's a camera when ya need one! walt

I have done quite a few with co2 or argon, and no embarrasing burp either. Do yourself a favor while it's cleaned out, and line it with Red-Kote (my favorite), Kreem, or some other "fuel tank sloshing compound".

wallster wrote in article ...

I, for one, would be interested in understanding why a gasoline vapor explosion caused by a propane torch is, somehow, of lesser energy - thus safer - than a gasoline vapor explosion caused by any other source of ignition......

Haahahaha. You just made me spit coffee!

rvb

On Sat, 14 Aug 2004 08:29:14 -0500, "Bob Paulin" vaguely proposed a theory ......and in reply I say!:

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I believe the torch is meant to be lit before application.

I also reckon the "friend" who suggested this should be invited to try it themselves.

***************************************************** It's not the milk and honey we hate. It's having it rammed down our throats.

I believe that would be like a comparison of 110v. and 220v. One will kill you. The other will only blow off a few fingers and knock you unconscious for a while.

Or was that vice versa?

It's been so long since the explosion, I don't remember.

Is the phone ringing?

bye

.......................

steve ........................ ;-)

wash tank with hot soapy water, then fill tank with water 95%, position tank so air pocket in the weld area, and weld your area.

Keep the cap off and you wont have a problem... I watch my friends at the junkyard cut up barbecue gas tanks... All they do is take a hammer and knock the valve off with a hammer and while the gas is coming out they cut the tank in half... Not something I would want to do...

220V merely tickles.....its what you're used to that matters...

Steve

Tickles, my ass. Try it hot and sweaty lying on your belly and brushing a 3 phase feeder. With very little room to maneuver away from it.

Garrett Fulton

Brrrrrr...the memories of something similar still haunt me....

Gunner

Depends where you're pointing....

Try it hot and sweaty lying on your belly and brushing a 3

phase-phase you're up to 415volts, that DOES hurt.

Steve

Worst I've seen was 50V - telephone exchange busbars. They'd deliver a squiggaamp and not break a sweat. At least 230V usually has some sort of fuse somewhere.

Lately I've been zapping myself with 12V - the electrolytic derust tank, because I'm still to stupid to always switch it off before going near it. It's "only 12V", but across two hands that are wet with salty water, you sure feel it.

Yeah. And it was 400 cycle too.

Garrett

I just got bit pretty good week before last - 277V from the base of my left index finger to one of my forearms laying on the rim of the steel access hatch in grounded steel lath ceiling falsework... Wa-Ha-Ha-Hoooiee!!! Was repeating George Carlin's "Seven Dirty Words" routine for 30 seconds ;-) and shaking my arm for a half hour...

Compared to that, 120V is nothing but a strong tickle. The little (1/8" x 3/8") 2nd degree burn where the wire touched at the edge of my palm (almost on my thumb web) made a dry blister and is healing up nicely.

G--D---ed retail store in an old office building, with the 277V panel for those lights locked up in another office's utility closet. Which made it far easier to pull the wirenut in the ceiling to kill the fixtures we were replacing two at a time...

Moral: Copper wire makes a decent spring and can jump sideways to bite you when you take the wirenut off.

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