Topic: Welding up my tank

[chrisf]

Having read horror stories of blowing one's self up, does the following sound reasonable?

1.) Flow water through the tank for 30 minutes.
2.) Put dish soap in the tank, then flush out for another 10-15 minutes
3.) Weld away on the tank.

Seems you guys have done this quite a bit. Is it worth it to pump a bunch of CO2 in the tank before welding? The tank is going in for powdercoating, so I'd hate for it to blow up their oven!!

--Thanks, Chris

[tmht]

If it's going for powder coating anyway, why not just have it hot tanked? That would get rid of any varnish and what not left in the tank. I believe there is a place here in NOLA that will do a tank for about $20. I can't imagine we are cheaper than anywhere else.

[johnny-from-bel]

From the hobartwelders welding forum

Thourough cleaning and degreasing, followed by purging with CO2, nitrogen, or inert gas should do it. Lots of cleaners to do the job, but I woud probably go with something like simple green, agitating the tank for a good while, drain, and repeat several times. Use a light and inspection mirror through the ports befre beginning to identify any locations that are crudded up bad, and you may need to blast those spots with a stream. KEEP THE TANK VENTED and filled with inert gas while welding.

Now if it is to repair holes just solder them I have done that many times with great success

[jevfro]

pipe solder or the big sticks of lead like the used to use for body work back in the days before bondo... just remeber to ventilate.
Also a easy to find source of inert gas for purging gas fumes is dry ice. 

[chrisf]

The dry ice is a great idea. Stick a few cubes in a well cleaned tank, put a little water in and weld away. I think I'll try that. I was thinking of buying a couple helium balloons and using that.

--Thanks, Chris

[johnny-from-bel]

pipe solder or the big sticks of lead like the used to use for body work back in the days before bondo... just remeber to ventilate.
Also a easy to find source of inert gas for purging gas fumes is dry ice. 

Yep, pipe solder like plummer use, don't forget the flux.
Take a big electic soldering iron, 150 Watt or more. If you do that you do not need to fill the tank with C02.
Do not use a blowtorch

[babyfood1217]

Body solder is a great idea, but if you are considering powdercoating, won't the heat from that process compromise the surface of your solder patch job (I've never had powdercoating done, but I think temps around 200 degress celcius are not too uncommon.)  Just curious though.  I've done some pewter and lead work, and I know temps are pretty low.  Keep us posted.

Good Luck.

-Chris

[v4hor]

I knew a guy that used to weld auto gas tanks.  He claims that he prepped them by using water and baking soda to neutralize the gas.  I've used baking soda to deodorize alot of things but never anything with these consequences.  I thought I might try it here in the next few weeks when I paint the bodywork on my old whore (she's a little old and rough but gets by on her charm).  Good Luck on the whole not-blowing-up thing.

[tbone]

I usually purge tanks with a 75% argon-25% Co2 mixture. That's the gas that I use on my mig welder.
I weld them with a tig welder which uses 100% argon.
Co2 would probably be cheaper but who needs another tank to fill. 

[pyro139]

If it's going for powder coating anyway, why not just have it hot tanked? That would get rid of any varnish and what not left in the tank. I believe there is a place here in NOLA that will do a tank for about $20. I can't imagine we are cheaper than anywhere else.

lol think again, $150 here in toronto to hot dip a tank

[mrblasty]

I've never blown my self up by simply filling the tank with water and flushing the fumes out that way.  As an extra step I blow dry the inside of the tank with compressed air.
Remember, its the fumes that explode.

[merc2dogs]

I've never blown my self up by simply filling the tank with water and flushing the fumes out that way.  As an extra step I blow dry the inside of the tank with compressed air.
Remember, its the fumes that explode.

 that's the way I've always done it.
 It's also the recommended way to do it if you want/need to cut a propane tank.
  The smell will still be there in many cases, but the explosive potential isn't.

Ken.