tank cutting

SE18

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I'd like to do some aluminum casting and watched some videos. I don't have the link handy but one guy used a metal cutoff wheel on a grinder looking device to cut open an oxygen tank which he then lined with a blanket of that ceramic thermal fiber stuff.

So my questions are:

1. WIth all the sparks flying, could the oxygen ignite inside the bottle? Not sure if it's flammable.

2. Yesterday, someone threw away this can for helium. Would that explode if cut into; or perhaps the top can be pulled to let the helium out?

I definitely don't want to do something that would earn me the coveted darwin award!

thanks

btw, I didn't see a section on the forum on metal casting or foundry like for blacksmithing. If anyone knows a forum or site that deals with those 2 areas pls let me know, as the links would not IMO compete with this.

thanksIMG-20141125-00117.jpg

IMG-20141125-00117.jpg
 
Oxygen is not flammable, but it does accelerate combustion. You could flush the tank with air prior to working on it. The biggest danger would be any pressure in the tank. Leaving the valve open when working would be the safe way to do this.

Helium is completely inert. No danger at all. Make sure the tank is not pressurized. Leave the valve open.
 
I've had success depressurizing a tank by drilling an 1/8" hole in it. Of course, it was nearly empty anyhow.
 
Some valves may need a mating fitting to allow the gas out even if the valve is open so be careful( propane) . I'm not familiar with that type of helium tank so I don't know if it needs a fitting or not. I have always drilled a small hole one I thought the tank was empty just to make sure. Then I will take the valve out and fill with water if it had flammable gas.
 
The helium tank is similar to what folks in the heating and AC and refrigeration business get freon in...

They are one time use and throw away.

Usually I drill a hole in them, and take them to the metal recycle yard.

To work on them... first be absolutely sure there is no pressure in the tank. Better to do as noted, and drill a small hole.

As to cutting, it is mild steel, so cut with whatever works. A sawzall is too rough, a cut-off wheel in a mini-grinder would probably be better... however be sure there is a guard on it... the wheels sometimes come apart when pushed too hard.
Would ruin your productive day... :nuts:
 
You never know for sure what combination of gases may be in a closed container like that tank. You need to depressurize then remove any valve . I have always then filled with water and cut with whatever tool is best suited, keeping the tank set so that a bubble of air is at the top while cutting. The water will displace any gas in the tank before you start so even if you don't leave the water in, you can be sure that there are no traces of the original contents. (However just the heat of cutting tools.. could.. cause the inside of the tank to emit something flammable).. ***It's VERY dangerous to cut something like that with a torch as you are liable to be introducing into the closed space the very flammable (explosive) gas mixture that you try to remove. I'm not sure about plasma cutting though as I don't have any info on that. Plasma cutting usually uses air as the plasma source, but I seem to remember that other gases might work, like argon or co2 :thinking:??
 
Just my 2 cents but I have an automotive back round as I had my own repair center for over 30years. We had many of this style tanks, they were used for Freon for air conditioner systems. thru the years we would cut many of them in two and used the lower halve to use for many different things but the one thing they were used for years ago was for portable air tanks. The parts store back than sold a kit that converted the upper valve to 1/4in copper fittings and came with the hose and all. The only main thing was that you needed to drill a hole to install the valve to fill it up. The fitting had to be welded or brazed in. I still have one of these today and it is set up with two tanks for a little more capacity. Never had a problem with cutting them we used a small air saw,same as a sawsall except a lot smaller. I guess if the tank was filled with a gas you would have to make sure it was empty before cutting it up. Also just thought I would add that when I had a 500gal. fuel oil tank removed from under ground the guy that did that job used a sawsall to cut it up after getting it out of the ground.
 
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