Cutting open a propane tnak

[ChrisB]

I have a empty propane tank that I would like to use as a forge body. The valve was removed a week ago. My plan is to fill it with water and use a cutoff wheel on a grinder to open it up. Any other tips?

[orgtwister]

well chris for safty reasons you shouldn't use one but i have done this a hundred times with out any problems i take the valve out fill with water untill it over flows and let it sit then dump it out and cut it up i like to use a jigsaw with a metal blade just drill a hole and start there it makes a nice cut in my opinion i use the tanks for all kinds of stuff and they are plentyfull since they changed over to the new tanks a few years ago and i have 10 or so around just wainting for my next project

[keykeeper]

Well, I'll give you the response I got on here a long time ago reference cutting into tanks such as this....

Don't do it, will go boom,
you'll find yourself in another time zone, etc.

Just passing on what I've been told in the past by the much wiser than I forefathers who will also chime in shortly, I'm sure.

(It's almost like they have an alarm to jump in and correct me every time I post something.)

[John B]

Sorry Keykeeper, I am agreeing with you 100%

An experience from the past. Demonstration booked, melting and making a pitch mix for a repousse course in a supplied tube with a plate welded to the base as mixing/melting chamber.
The chamber looked OK, but when heated, the pitch started oozing out from the welded joint at the base. Tube apparently was from a scrap pile, looked like steel but was some form of a cast iron, ordinary rods had been used to weld the base on. The item had been made and supplied by someone else to save time on the demonstration, however as we were heating from the base with a naked flame, it was thought to be imprudent to continue using this item.

There was an old propane cylinder at the back of the workshop that was just the right size, so with lot of consideration, the remaining gas was vented, the valve assembly removed, (Brass, we can melt that down for a casting course), tank filled with water from hose until overflowing from the top orifice where the valve fitted,

Then taking an small angle grinder (4.5" 115mm diameter), fitted with a thin stainless steel/steel cutting disc approximately 1/16" thick, cut through the tank and around the circumference whilst still full of water, this cut out the chance of a spark igniting the air/gas mixture that may have been in the tank (Surprisingly my audience had disappeared by this time) Taking care not to get water into the disc grinder (A pneumatic disc grinder would be better for this, but one was not available at the time)

After the top portion was removed, the water was then tipped out, and the sharp edges removed, handles were then welded on to allow the pitch mixture to be poured into boxes after melting and the tank was ready to use.

I then checked to see if I needed to change my undergarments, not this time, but a close call.

I am not advising doing this, merely recounting something that has been a personal experience,
It is very a dangerous practice, but like most dangerous processes, it can be done with care and careful consideration to the situation, just eliminate all the potential dangers.

[CurlyGeorge]

Another option may be the old freeon(sp) canisters that are just a tad smaller than the 20 pound LP tanks. Sometimes you can get an empty from a Heating and A/C Service place. I don't know if they are as thick, though.

[JWBIRONWORKS]

I have cut many 20#,40# and 100# tanks by removing the valve then filling the tanks to overflowiing with water,Dumping the water out, refilling the tank to full and then cutting the top out with a torch or a plasma cutter with the tank still full of water.
But maybe god just looks out for fools and children and at times I qualify as both

John

[nett]

My next-door-neighbor, the fire Captain says, "remove valve, fill with water, dump water and cut". He also suggests I not do the cutting while his wife, the Mayor, is having an outdoor luncheon. The Captain always gives sage advise.

Same advise on O2 bottles (CO2 isn't a problem), but NEVER mess with an Acetylene tank.

[dablacksmith]

hum i have done this but i used a bandsaw... i just cut part way then moved it ect.... with bandsaw there is no heat or sparks so nuthing to ignite and go boom...

[meancoyote]

I cut them often. I take off the valve and fill them with dish soap and water and let it sit for a week or two, then cut with a torch or plasma cutter.

[jimmy seale]

i've cut tanks to 250 gals. liquid measure.same fill with H2O and cut low to drain. still here, but be aware of old butane tanks-that is more unstable than propane. and never mess with acuetalene- if in doubt, don't.also you can vent with vehicle exhaust- i do not recommend this, but , it's bettern nothing! but be careful and safe doing what your going to do. by the way for reference a propane tank needs 30% capasity for vapor, so actual capasity is 30% more=if your calculating for liners and such you'll need more than expected, be safe! jimmy