Cutting Into a Propane Tank

[Steve Sells]

So why do guys weld on gas pipelines??? for $ and because they enjoy it...why do guys fight fires? they enjoy it!!!!

I am primarily a construction worker, I can state that the pay is good , but so is the TRAINING, they have certs for pipeline welding, they are not people asking unknown yahoo's on the internet for opnions, rather they went to school, learned the craft, and took the tests.

But do it your way, just PLEASE not a night I am on call, as I am ARC+EMT and don't want it to be my squad that has to clean up the mess.

[Woody]

I have two gas forges, one was made out of rolled sheet metal and the other was made out of two 20 lb propane tanks that I cut and then welded together. I vented all the fumes from the tank, then filled them with water completely and drained them several times. Then I cut them with a metal cutting blade in a sabre saw. When I was done welding the two pieces together, I happened to have it sitting right beside my bucket of quench oil. The similarity in size was amazing.

Then and there I asked myself why is everyone so set on building a forge out of a propane tank. All the metal shell of the forge does is support the insulation. Why not get a 6 gallon steel bucket like the ones that popcorn popping oil come in and use that. If and when I build another one it will be made from a bucket.

[keykeeper]

So far I've read some informed opinions, the straight dope and some outright . . . Nevermind.

From what I've heard I have to say don't do it! You'll kill yourself doing something that's reasonably safe if you follow procedure but you aren't going to. What you're going to do instead is follow the advice of some internet wahoo that doesn't know diddly but has an opinion about everything. Why? because not knowing anything you'll THINK a pants load of mock and ineffective gobbledy gook precautions SOUNDS good to you so that's the way you'll go.

Go find another clean tank to use for whatever it is you want to cut a propane tank for. You don't know enough to do this safely and you don't know enough to pick the good advice from the really BAD advice thus far posted.

Be safe, find another alternative.

Frosty

I have to agree with Frosty on this one. I posted before about this on another similar thread. Might I remind everyone that the fellow said "250 and 500 gallon" tanks some time back in thread. I think that equates to an even bigger buildup and subsequent, BOOM.

For a tank that size, I would think if you need two halves, just fabricate them someway out of a thinner sheet steel. I'm sure it would be faster and easier than going, BOOM.

When John Madden says, BOOMpeople think it's funny.

When someone we don't know personally, but was warned repeatedly about the dangers involved cutting into a propane tank GOES BOOM, not very funny.

(Anyone notice the common theme of this post?)

[homesteader]

I have been cutting up propane tanks for a long time and have never had one go boom or even pop. I remove the valve from the tank after exhausting any left over gas , slowly outside. Once the valve has been removed I let them sit for a day. Propane precipitates IE. it boils off. Once it has boiled off there is no residual gas.

[Glenn]

Reference Propane MSDS

Fire And Explosion Hazards:
Propane is easily ignited. It is heavier than air, therefore, it may collect in low areas or travel along the ground where an ignition source may be present.

ACCIDENTAL RELEASE MEASURES

Evacuate:
Evacuate the immediate area. Eliminate any possible sources of ignition, and provide maximum explosion-proof ventilation. Shut off source of propane, if possible. If leaking from cylinder, or valve, contact your supplier. Never enter a confined space or other area where the concentration is greater than 10% of the lower flammable limit which is 0.22%.

Inhalation:
Simple asphyxiant. It should be noted that before suffocation could occur, the lower flammability limit of propane in air would be exceeded; possibly causing both an oxygen-deficient and explosive atmosphere. Exposure to concentrations (> 10%) may cause dizziness. Exposure to atmospheres containing 8-10% or less oxygen will bring about unconsciousness without warning, and so quickly that the individuals cannot help or protect themselves. Lack of sufficient oxygen may cause serious injury or death.

[frogvalley]

One more point in regards to the dangers of these tanks. There is at times, for some reason unknown to me, an oily coating/residue in them that is also flammable. It may or may not evaporate or be removed by soapy water. When heated by flame cutting or saw cutting, it can become volatile again and explode or catch fire.

I have made small propane tank forges, but my newer forges are being made from pipe or rolled steel, because of the risks.

And I believe these small forges were originally made from FREON tanks once easily obtainable. When those became less available, empty propane tanks became the norm. At least thats how I remember it, but then again i had to walk 20 miles barefoot through the snow just to get a coke and go to school so things were different in the old days.

[keykeeper]

I have been cutting up propane tanks for a long time and have never had one go boom or even pop.

Glad you are with us to tell us all about it, homesteader.

I play the lottery pretty frequently myself, but I've never won.....yet.:rolleyes:

[Frosty]

The oily residue is mercaptan (something or other else) the odorizing agent added to propane so you can smell a leak. Columbia Gas of Virginia - What is mercaptan?

Mix about 1 cup of chlorine bleach to 5 gl. water and fill the tank. Let it sit over night and drain it, the mercaptan will be gone as will the smell.

Frosty

[meinhoutexas]

if the man that started this is still with us i would like him to send me a note on the personal msg area. i have done this my dad did this and i will do this again but if you must have someone else do this for you i have a brother in the austin/bee caves area

[oakwoodironworks]

I always tend to lean toward the safe side of things. Been hurt enough. Like one old fella told me one time, you've got to be tough if you are going to be stupid. I wonder how they make the BBQ smokers that I see made out of the 250-500 lb. propane tanks. There seems to be a lot of them here in GA.

[petew]

read a book called gas burners for forges furnaces and kilns by michael porter printed by skipjack press this will tell you all about it

[Ten Hammers]

Actually, the "L "word ( liability ) scares me as it should. Local gas company has a couple of 15,000 gallon LP tanks. They needed some work ( another valve issue of some kind ). Professional trade company came and purged air into the ( now empty, in July ) tank. Purged for prescribed time ( unknown ). Fella crawled into the manway hole and to location of new fixture. Lit acetelyne and cut from inside out. Not my cup of tea. He was well paid for his work.

There will always be some sort of risk involved in some types of work. I would caution anyone thinking about cutting fuel tanks. I have done it yes ( and survived ). Carrierizing main mount aircraft tires to 800 lbs ( nose to 600 lbs) even from the tread side was scary but after a time it became mundane. Approaching hot brakes on a runway was scary too. Other NOS tanks will work for what you wish ( apparently forges ). Rolled sheet or pipe ( capping ends ) works too. I have done more than one dangerous thing in my life but choose not to continue to roll the dice. Local Fire/EMS do not have need for skill building on my account. Life is good. Wear the glasses when you cut or grind. You want to see your grandkids later in the day.

[Ian]

Propane or butane tanks are designed to contain a liquified flammable gas. They're pressure vessels and are built as such The fact that they are often of a shape and size that makes them potentially useable for other purposes is mint imperial (immaterial). They are meant to hold liquid gas, end of story.
Cutting into an empty tank is potentially very dangerous, and is not something to just 'go and do'. John N offered up advise similar to what I would have done, firstly make sure ALL the liquid gas has emptied out and crack the valve wide open with the tank upside down. Leave it for at least 24hrs then VERY carefully remove the valve. Fill the tank with water till it overflows. Water doesn't want to burn anywhere near as much as Propane or Butane in my experience and if the tank is full of water it CANNOT be full of anything else.
Empty out the water and then begin cutting the tank. Abrasives or saws are better than gas axes.
I would NEVER, EVER, EVER cut into any gas tank than hadn't been FULLY purged first.

[Glenn]

Why empty out the water before cutting?
If the container was 3/4 full of water that would seem to leave only 1/4 to be filled with something else, explosive or otherwise.

All this supposes that you wish to risk life and limb to cut into a talk that MAY go BOOM. There are too many other options are out there that can make a usable forge body.

[SLOB]

forge and burner book on google books

Gas Burners for Forges, Furnaces ... - Google Book Search

[Glenn]

IForgeIron is a world wide forum that promotes safety. A bad day at the forge is always better than a good day in the hospital. Just because it can be done, we err on the side of caution as the next newbie may not take the time to read the entire post or warnings about propane tanks. Safe to you may not be safe for them, as each individual and their circumstances are different. For instance your torch may be properly adjusted, theirs may not. You tank may be fully purged, theirs may not.

There is nothing wrong with taking the propane tank to the fellow that "knows how", jumping in the car and going to get you both lunch while he cuts the tank open. If something goes wrong, you will have food to give to the first responders, and his widow.

As in any action the individual must educate himself as to the procedure, weigh the risks, and make an informed decision. Whatever you do, please do it safely.

[Larzz]

As an ex-machine maintenance mechanic in a large machine shop (up to 75 ton per part) , 26 years as a boiler inspector and boiler machinery insurance inspector along with 8 years in Uncle Sam's Canoe club (underwater division).

While I know how to cut up a large tank of that size. Drain, vent, purge, sample the atmosphere, if possible add an inert gas (nitrogen). Then carefully cut with a plasma cutter. While doing it I would be on pins and needles, wishing I wasn't. There will always be a large element of risk in doing something like this.

Another item nobody has questioned so far is are you sure only propane has been in the tank? Could someone have used it for something else along the way? Unkown tank contents will carry unknow dangers!

I saw someone mentioned old freon tanks, another area that has it's own pitfalls. Freon + Flame = Phosgene gas. Well known in the first world war. The use of freon as a cleaning agent is also well know in the welding communitiy. A whole lot of headaches and lung problems.

Bottom line-----not a good idea.