ChrisB Posted October 18, 2008 Share Posted October 18, 2008 (edited) 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? Edited October 18, 2008 by ChrisB Quote Link to comment Share on other sites More sharing options...
orgtwister Posted October 18, 2008 Share Posted October 18, 2008 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 Quote Link to comment Share on other sites More sharing options...
keykeeper Posted October 18, 2008 Share Posted October 18, 2008 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.) Quote Link to comment Share on other sites More sharing options...
John B Posted October 18, 2008 Share Posted October 18, 2008 (edited) 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. Edited October 18, 2008 by John B Apology to previous post, considered reply Quote Link to comment Share on other sites More sharing options...
CurlyGeorge Posted October 18, 2008 Share Posted October 18, 2008 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. Quote Link to comment Share on other sites More sharing options...
J W Bennett Posted October 19, 2008 Share Posted October 19, 2008 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 Quote Link to comment Share on other sites More sharing options...
nett Posted October 19, 2008 Share Posted October 19, 2008 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. Quote Link to comment Share on other sites More sharing options...
dablacksmith Posted October 19, 2008 Share Posted October 19, 2008 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... Quote Link to comment Share on other sites More sharing options...
meancoyote Posted October 19, 2008 Share Posted October 19, 2008 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. Quote Link to comment Share on other sites More sharing options...
jimmy seale Posted October 19, 2008 Share Posted October 19, 2008 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 Quote Link to comment Share on other sites More sharing options...
Glenn Posted October 19, 2008 Share Posted October 19, 2008 The concern of this thread is that you CAN do something 100 times and not have problems, but the very next time things can go terribly wrong. We need to caution those that would undertake cutting open closed containers that there is a danger involved. The safe way to cut open an container is to have someone else do it while you leave and go get lunch for both of you. They should have the container open by the time you return. Second word of caution. NEVER trust a label. Just because there is a label on the outside, that does NOT mean that is what is on the inside of the container. One time I picked up a 55 gallon drum clearly labeled anti-freeze. Loaded it onto the truck and a fellow walked past and said you may want to be careful with that one, cause they put the racing methanol left over from the weekend drag races in it. I returned it to the side of the building even though it was empty. Thank goodness for friendly strangers. Quote Link to comment Share on other sites More sharing options...
Sam Thompson Posted October 21, 2008 Share Posted October 21, 2008 I too have cut hundreds of these without any problem... I'd be interested to know if anyone actually knows of an explosion, I believe that it is a myth propagated by gas companies to stop people cutting up their bottles. Another safety precaution is to fill the bottle with argon or CO2 Quote Link to comment Share on other sites More sharing options...
John B Posted October 21, 2008 Share Posted October 21, 2008 Yes cylinders do explode if not treated with the utmost respect, The guy involved did not get a second chance, and his assistants will never attempt it again. This incident was terminal and unfortunately is not a one off. Quote Link to comment Share on other sites More sharing options...
Trollhammer Posted October 22, 2008 Share Posted October 22, 2008 According to my step-father, he has first hand knowledge of a tank exploding. At one of the plants he used to call on(Amoco, Nutrasweet, ADM, International Paper...one of those) a guy was in the shop straddling a tank with a torch. He's not sure what the guy was attempting, but he and the crew he was with heard an explosion, and the tank was gone, and the guy was falling back to the floor...dead before he hit apparently. The tank went through the ceiling, the guy did not. He swears up and down this is true, and judging by his reaction to catching me cutting the top off of a 55gal steel drum with previously unidentifiable contents, I'd be apt to believe him. Either way, even if it is simply a myth, the possible risk is enough to keep me from doing that again unless absolutely neccessary...with proper precautions. I've gotten away with far too much that could've/should've killed me, I don't need to tempt fate any further. Mickey Quote Link to comment Share on other sites More sharing options...
Mulciber Posted October 30, 2008 Share Posted October 30, 2008 According to my step-father, he has first hand knowledge of a tank exploding. At one of the plants he used to call on(Amoco, Nutrasweet, ADM, International Paper...one of those) a guy was in the shop straddling a tank with a torch. He's not sure what the guy was attempting, but he and the crew he was with heard an explosion, and the tank was gone, and the guy was falling back to the floor...dead before he hit apparently. The tank went through the ceiling, the guy did not. He swears up and down this is true, and judging by his reaction to catching me cutting the top off of a 55gal steel drum with previously unidentifiable contents, I'd be apt to believe him. Either way, even if it is simply a myth, the possible risk is enough to keep me from doing that again unless absolutely neccessary...with proper precautions. I've gotten away with far too much that could've/should've killed me, I don't need to tempt fate any further. Mickey Yeah this happens, but people get hit by busses and other stupid things too. I think the story here is don't be a moron. You can't blow up if you don't have any gas in the thing. So! fill with warm soapy water and drain, leave it for a day upright where it's above 60 degrees. Any remaining liquid or vapor will be gone. Saw away! The fools that get hurt doing this probably don't understand that there's explosive gas in the tank before they start cutting. Personally I would take a sniff to see if there's gas still in the tank. If there is then flush with something non explosive. It's nearly impossible to fill with warm water and still have gas remains due to the nature of propane being a gas at room temperature. I'm going to cut mine open. I have an old 30lb'er that has an unusable valve on it. Definently my next forge. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 30, 2008 Share Posted October 30, 2008 The other problem is that if you cut with a cutting torch the torch itself can fill the tank with enough unburned gas to create an explosion---why they suggest you cut tanks still full of water if you are using a torch. Messy though. Quote Link to comment Share on other sites More sharing options...
Pipeliner32 Posted October 31, 2008 Share Posted October 31, 2008 If you can, purge the tank with nitrogen several times, this should help remove the hydrocarbons. Pipeliner32 Quote Link to comment Share on other sites More sharing options...
territorialmillworks Posted October 31, 2008 Share Posted October 31, 2008 Salvaging of oil tanks is often done be purging with dry ice or nitrogen. I'd still flush with water then dump the dry ice in and wait a respectful time for it to melt and fill with inert CO2. When I was young, I welded gas tanks by inserting a large dia hose from the exhaust pipe of a car and letting it run but I wouldn't do that today! God seems to look after stupid people, proved by me writing this.... Quote Link to comment Share on other sites More sharing options...
ChrisB Posted November 1, 2008 Author Share Posted November 1, 2008 Its been sitting for over a week filled with water. I havent touched it yet. Quote Link to comment Share on other sites More sharing options...
phil shelton Posted November 1, 2008 Share Posted November 1, 2008 ask you kids what they would do with out a parent or one with no eyes or a missing limb if you don't have kids then decide if it is worth it to save a few dollars or gamble not worth it to me PS i spent 40 years in the welding business welding on every type of vessel that had all kinds of hydrocarbons in them their is no guarantee on removing all of it none of them are Worth the chance Quote Link to comment Share on other sites More sharing options...
Hillbillysmith Posted November 2, 2008 Share Posted November 2, 2008 I seem to remember a guy that used to have a method to use a torch to cut them open. He never had a problem in the 25 years he has been doing it (and he has done them to the BIG 2,000 gallon tanks from big businesses) but I can't remember for the life of me what his procedure was for doing this and I don't want to give any unsafe info on doing this. Filling with water and using a "sawzall" would be your best bet because the saw will not make any sparks. Cutting a propane tank open is dangerous business because propane is in a liquid state inside the tank, it deposits into the pores of the tank. Personally, I would leave the valve off for a couple of weeks and then take it somewhere open where nobody is around and flash the tank out. (But this is just me). Don't go doing this if you have never done things like this before!! I would feel extremely horrible if someone got hurt. -Hillbilly Quote Link to comment Share on other sites More sharing options...
Neal L Posted November 3, 2008 Share Posted November 3, 2008 The concern of this thread is that you CAN do something 100 times and not have problems, but the very next time things can go terribly wrong. We need to caution those that would undertake cutting open closed containers that there is a danger involved. The safe way to cut open an container is to have someone else do it while you leave and go get lunch for both of you. They should have the container open by the time you return. Second word of caution. NEVER trust a label. Just because there is a label on the outside, that does NOT mean that is what is on the inside of the container. One time I picked up a 55 gallon drum clearly labeled anti-freeze. Loaded it onto the truck and a fellow walked past and said you may want to be careful with that one, cause they put the racing methanol left over from the weekend drag races in it. I returned it to the side of the building even though it was empty. Thank goodness for friendly strangers. Antifreeze can be flamible also. According to an msds sheet on ethelene glycol antifreeze the flash point is 250 degrees F. i actually know of someone having their eyebrows burned off by using a lighter to check coolant level. Point being know what you are dealing with. Quote Link to comment Share on other sites More sharing options...
Hammered Posted November 3, 2008 Share Posted November 3, 2008 I successfully cut open an empty propane tank back in the spring when I built my gas forge. Removed the valve, filled it to overflowing with water about 5 times to flush it. After repeated flushings the thing still REEKED. I'm told that propane is actually odourless. They apparently add something to it to give that awful smell so that propane leaks don't go undetected....same as natural gas. At the time I left the tank sitting outside for another week, flushed it again, and partially filled it once again before cutting it with a cutoff wheel. Successfully cut both ends off the tank without blowing up, but had visions of something horrible happening the entire time. (I should mention that the propane smell hung on to those cut pieces for about another week or two.) If I had to do it again I probably wouldn't. Either opt for an automotive freon tank (they tend to be slightly less in diameter than propane tanks, but still have a fairly thick wall), or change your gas forge design (if that's what you're building). Quote Link to comment Share on other sites More sharing options...
keykeeper Posted November 4, 2008 Share Posted November 4, 2008 Here's an interesting read about cutting into tanks.....The Aboveground Steel Storage Tank ... - Google Book Search Scroll down near the bottom and read about the FIREFIGHTERS cutting into a tank with an abrasive saw!! Quote Link to comment Share on other sites More sharing options...
metalmaster1766 Posted November 5, 2008 Share Posted November 5, 2008 i have cut several propane tanks with no problems at all if you have any fear of it at all, dont do it after taking the valve out, fill with water along with dish soap, refill several times, let sit several weeks before cutting i did an experiment once, after rinsing with water several times, i threw a lite match into the valve hole to check for flammability, it did shoot a small flame straight out the top and made the woooooofff sound, nothing to get excited about again most times i use a grinder and cuttoff wheel to cut tanks with, i leave the tank filled with water while cutting do at your own risk, dont take anyone's word for it that it is safe, because anything can happen Ron Quote Link to comment Share on other sites More sharing options...
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