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Up Topic Welding Industry / General Welding Discussion / another aluminum diesel fuel tank welding question??
- - By Chris2626 (***) Date 11-30-2013 15:45
I know i have seen from time to time people asking about welding on aluminum diesel fuel tanks and i have a guy wanted me to weld on two of these tanks he said it has been flushed really well with water but you still don't want to trust that. I have also read a lot and a friend told me he usually will fill that tank completely with water and leave the water in that tank as he welds on them or purge it with argon or nitrogen.

You guy have never steered me wrong on anything here, if I completely fill them with water will it be ok to weld on these aluminum tanks?? I will be using tig process and was thinking of going up on the price as well for the danger factor.

Thanks
Chris
Parent - - By 803056 (*****) Date 11-30-2013 19:55
Are you repairing a leak, adding brackets, or what?

Do you know the alloy?

Al
Parent - - By Chris2626 (***) Date 11-30-2013 22:25
I kinda think it could have a crack in it but hell if it has a crack it probably wouldn't do any good to fill with water because i'd have a hell of a time welding it with water coming out. I don't have another argon tank anyways to purge the thing well I do have a mixed gas though, so water would have to be the best bet. I would think also if it needed a bracket i would still fill that sucker up with water to. The guy is bringing one of the tanks by tomorrow for me to look at it.

I don't know the alloy, I'm sorry I know there isn't much info to go on here.

Say it has a crack in it would it be just a good idea to send this guy on his way? This is my dads friend and I have no problem telling the guy to hit the f ing road I'm not wanting to blow myself up for him. Personally if i wanted fuel tanks for a boat I'd buy new ones rather then use old junk tanks that getting to be to cheap. I would be rasing the price no doubt on the tanks if purging is needed.

Chris
Parent - - By lo-hi (**) Date 11-30-2013 23:45
The biggest problem filling with water is, any  space left  will be a concentration of vapor directed at the welder. Purging with any inert gas used for welding will prevent combustion, just be careful of pockets that could hold vapor. I have done quite a few steel diesel tanks and more than my share of gas. Even some aluminum fuel cells on aircraft and stock cars. A good purge is very important.  good luck and be careful  Perley
Parent - - By Chris2626 (***) Date 12-01-2013 01:23
Thanks and after more reading and talking to people i think i'm gonna pass this one on up this guy is cheap as it is and i doubt he will want to pay more.

Thanks
Parent - By Sourdough (****) Date 12-01-2013 15:59
Chris, nitrogen negates oxygen. If you purge a tank with nitrogen, there will be no oxygen whatsoever to ignite. I do this all the time, as well as hot taps on live gas lines. No oxygen = no ignition.

If there is a return line to the tank, you can purge with nitrogen. Purge it, seal it back up and weld the crack.

Don't pass these jobs up. This kind of thing will set you apart from other "welders"!
Parent - - By cajun welder (**) Date 12-01-2013 01:38
What about using carbon monoxide. Iv'd watched several old timers repair propane, gas, and diesel tanks using carbon monoxide. I helped a welder down the road from me earlier in the year cut a 150 gallon propane tank using carbon monoxide. If your not comfortable or your gut is telling you something, pass on it.
Parent - By Chris2626 (***) Date 12-01-2013 02:05
Thats what I'm saying my gut is telling me different on this one.
- - By Dualie (***) Date 12-01-2013 10:32
funny thing about it, you don't hear about the ones that didnt go well.

Dead men tell no tales.
Parent - By Chris2626 (***) Date 12-01-2013 15:14
They sure don't haha
- - By americaniron (*) Date 12-02-2013 15:13
I have welded many diesel tanks without purging.  Diesel does not explode like gas.  Clean it the best you can with something that does not burn, tig weld it, lay a patch over it, weld it on for insurance, leak test with air.  Easy repair, I have even done tanks with fuel still in them, as long as there is no fuel leaking through the crack or within a couple of inches of it.  DO NOT DO THIS WITH A GAS TANK!
Parent - - By Chris2626 (***) Date 12-03-2013 11:31
Thanks guys, I will do one later on but just not from this person, this was a nightmare dealing with him.
Parent - By Tommyjoking (****) Date 12-07-2013 01:58
Cheap way to do it is a few lbs of dry ice in the tank....wait till its smoking out the topmost outlet....weld away.
Parent - By NMWELDING (**) Date 12-09-2013 03:22
I weld on old vessels and old rivited oil tanks quite regular doing patch work  in the oil fields. They cannot be cleaned out because the old ones have no manway. As much crude is pumped as possible,and then I purge it with exhaust (carbon monoxide). It always works, just make sure its purged long enough.
Up Topic Welding Industry / General Welding Discussion / another aluminum diesel fuel tank welding question??

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