Anyone know how to cut open an empty disposable propane tank?

[zxcvbob]

Do you have an idiot brother-in-law?

Doesn't everyone? (just ask your wife's sister!)

[gotin]

I did it for my melting pot.
Run it on a barbecue grill until its empty. Then screw in an open end hose in, there is a pressure valve that will prevent gas leaks if it is not connected to an appliance even after you open the valve.
There is always some gas inside, so leave it open for a day or two, upside down, so the heavy gas can get out.
Spray WD40 on the valve, leave it for a day or two. I had to tie it with straps to a pallet and used a monkey wrench with a long extension pipe to break the locktite on the valve treads, after that it unscrews easy.
After you remove the valve, again leave in the open upside down for a day or two. Filing it with water 2 or 3 times is also a good idea, it pushes all the gas out.
Then just use an angle grinder or a metal cutting circular saw to cut it.
Just in case, make sure the valve hole is pointed away from anything important.

Cutting mine was easy, I had to cut it pretty shallow so I can melt range lead, too deep and I could not scoop the jackets out, now it holds about 50-60 lbs of lead.

[badbob454]

take it to a muffler man he has a pipe cutter that works like a tubing cutter , no sparks no heat ... it looks like a chain type oil filter wrench with sharp rollers ...

[floydboy]

I opened the valve and sat it upside down for a day or two. Filled it with water and let it drain for another day or two. Tried to take the valve off but couldn't get it to budge. Ended up building a small fire and threw it in with the valve open just to make sure it would not blow up. After it cooled off I cut it with a torch with absolutely no problems but would not advise anyone trying this. If you are going to do it I would put it in fire of some sort first.

[dnotarianni]

If you put it in the fire first you won't have to cut it open later!

[uccm25]

It's funny this subject should come up. I had an old Mapp gas cyl. that had a lot of rust and dirt in the port and wouldn't seal on my burner nozzle even after trying to clean it. What do I do??? I took it down to my bottom ground, stuck it in a tree crotch, backed off 50 paces, and shot a hole thru it with a .22. It did a couple of flips, landed on the ground, and emptied itself. Don't try this unless you're a Veteran. Now I can turn it in for salvage.
I think the pipe with piece of plate welded on the bottom is a better solution for your aluminiun casting. Regards and God bless all...

Guy

[Plate plinker]

Bam... Just shoot it.

[jmorris]

I read your post so I understand what tanks you are talking about, I have a pipe cutter that is large enough to cut them open but I have always used a band saw. I have only used two methods to ensure they didn't blow up on me. One was the bullet hole method above the other was burning them. I wouldn't tell my kids to do either but both have worked for me.

[jimb1972]

Why not just use a piece of 3 or 4 inch black pipe with a cap screwed on one end?

[whtsmoke]

single wrap of det cord and stand way back.

[Salmon-boy]

Ok, I'll add my session of idiocy here. I've done 3 or 4 disposable oxygen bottles without incident, so will be doing a couple of empty propane bottles too.

1) Screw in a torch-head and open the valve. Make certain nothing is coming out.
2) Clamp securely in a vice.
3) With a hacksaw, slowly cut through the steel until there is a hole.
4) Wait 5 min.
5) Continue till there's a 1 inch hole.
6) remove torch head and purge with water.
7) Wait 5 min.
8) While still full of water, continue hacksawing until top falls off.

I've done this with both a hacksaw and a Grizzly power bandsaw. Your mileage may vary. I am not, and will not be held responsible for your stupidity. Do not smoke while performing the operation described herein. Please keep hands and feet inside the vehicle at all times. Not responsible for typographic errors. No animals were harmed in the testing of this procedure, but a few lawyers are probably cringing/salivating somewhere..