- Thread starter diogofcr
- Start date
Personalty I would not. I made a compressor out of a large one and later a coolant tank out of another for my Lister CS. The coolant tank one I left empty with the valve removed for donkeys years but the compressor I cleaned out and filled with water then welded immediately. Never let a gas tank or fuel tank sit after washing out as over time the fuel vapours release out of the metal itself and explosive fumes build up in it again. BE VERY CAREFUL !
Laurence
Laurence
monkeh
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I'm in the process of making a forge from an old propane tank. I drained all the gas out, removed the valve, filled with water and emptied it, and left it upside down for a while. When i came to angle grind it open. There was no sparks or explosions and no kittens died.
gordon stephenson
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I have done quite a lot, And used to fill with water etc, Now I remove the valve, lay on its side and feed a 10mm tube on the end of my airline through e top hole down to the bottom and purge with compressed air for a minute, then cut/weld immediately, Never had even the slightest issue, Even after filling with water the propane " smell" remains but this is just an odour that is added to the gas and not the gas itself,
Burdekin
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I took the valve out of mine, washed it with fresh water a good few times, rolled it about and left upside down. Then cleaned with degreaser, rinsed, then swirled some bleach in, washed with water then added bicarb soda and three dishwasher tablets, let soak for a coup!e of days, then rinsed, swirled in more bleach, rinsed again and let soak with water and there was no smell. Bleach does seem to get rid of the smell in propane tanks but you need to wash the bleach out well as well.
I then drilled out two holes, flushed it with compressed air before tig welding on two threaded bosses. I went OTT but I wanted to ensure it was safe to weld but also didn't want my air smelling.
I then drilled out two holes, flushed it with compressed air before tig welding on two threaded bosses. I went OTT but I wanted to ensure it was safe to weld but also didn't want my air smelling.
brightspark
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now now don't be suggesting dangerous practices on forumI've found that washing them out with petrol gets rid of the gas smell quite easily.
there's one born every minute so someone may try it 
Burdekin
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now now don't be suggesting dangerous practices on forum
But they'd get a nice wee Darwin award so not all bad.
outofthefire
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That is kicking the proverbial out of it, i'd have been more worried about the chemical concoction you were swilling about but each to there own. I just take the valve off fill it with water then work on them.
Gas isn't absorbed by the steel (although the added smell does seem to linger) i've welded, cut and drilled a few and set most of them on fire to burn the paint off and the metal has never shown any hint of having flammable gas in its molecules. Your theory also presumes that steel is somehow porous which when you think about it logically would make it a most unsuitable for holding flammable liquids and gasses.
Thank you everyone, what I will probably do is just fill it with water and empty it right before welding and also run some compressed air to really kick everything out, I think it will work.
I am like 100% sure it is empty of propane the only thing is the odor which substance is also flammable and apparently it gets "stuck" in the steel
Bill Edwards
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People make such a big deal out doing this, as though there's something complicated or difficult about purging a cylinder of gas.
A good squirt of washing up liquid to remove the odour when filling with water, fill it right up then drain. And then do your hot work.
A good squirt of washing up liquid to remove the odour when filling with water, fill it right up then drain. And then do your hot work.
addjunkie
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I do this kind of stuff for a living on a much bigger scale. For gas cylinders the few I have done, valve off, vent. Water fill with hot water to flash of any vapours. Drain it, the purge with mig gas. And cut away.
Kent
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Unlike some I have seen vessels like this blow. I have gotten away with far dumber stuff but that was before I leant that I was actually mortal and "stuff" like this really happens. I know how to do it safely but then again not legally unless you actually own it. Last year an experienced welder lost his face and a good proportion of his head doing a plasma cut on an old oil drum. He was they say "lucky".
If I need such a vessel I will make one from fresh steel personally
gordon stephenson
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I think every single person cutting/welding on a gas cylinder is very apprehensive the first time, but wash/purge and set to straight away. The first one that I cut took a while to pluck up the courage, Wondering if I was going to be blown over my house roof or not, But as I stated, Now valve out, purge with compressed airi for a minute then cut/weld straight away,
A mate and I were discussing this same subject on Saturday about FUEL TANKS building up explosive fumes over time after having being degassed a few days earlier. My mate had this happen to him. He got away with it as he flashed it first with a welding torch at an arms length. When I worked on fuel road tankers we quite often had to do welding repair to tanks we always worked immediately after degassing. Have welded quite a few tanks myself over the years and you cannot be too careful.
Laurence
Laurence
Yes I am really afraid since its my first time :P I have even tried to throw a match in there to check if its going to blow first xD
Why?
