Safest way to cut a propane tank for making a smelting pot?

[Rickf1985]

I have several propane tanks that are out of date and the scrap yards will not take tanks. So I plan to make at least one of them into a smelting pot for lead and maybe another into a pot for zinc. I know that just diving right in with a cutting wheel is pretty much suicidal so I plan to use a uni-bit at slow speed with oil for lube to make a large enough hole to be able to fill the tank with water. That way I know there is no gas left in it. What do you guys do?
I already tried removing the valve but that is not happening.

[Minerat]

I cut the top guard off the tank so I can get at the valve. Then take a 12" plumbers wrench with a 4' cheater pipe, strap the tank to a solid fence post and lefty loosy it. They usually break loose, then fill it with water and dawn soap for a couple of days and have at it with a side grinder and cutting wheel.

[country gent]

I remove the valve and fill with dish soap and water about 1/2 full insert a pipe plug and roll around for a few minutes then drain. refill full with soap water and let soak for a few days drain and rinse with water one last time. it is now ready to cut.

To cut pick up a wide roll of wide masking tape decide where you want to cut and make a couple wrinkle free wraps around tank this gives a good straight line to follow. these tanks arnt all that thick. I strap it to a post and use a hacksaw to cut them, it dosnt take long once you break thru the wall. just roll the tank as you cut.

Take it to a propane delivery shop they have the tools and can take the valve out easily.

My last one I made I cut just above the bottom radius about and inch or so then removed the base and cut a 3" wide ring from the remaining welded it on the bottom to make a full dia stand for it. Really stable now.

I lean to the hacksaw over grinder or power tools as there is less chance of a spark if it didnt get completely cleaned out.

Above all be safe wear appropriate PPE, make sure its clean. Another trick is to run compressed air into it while cutting 10-15 psi should keep the possibility of fumes building up way down.

[Cosmic_Charlie]

Timely post. I have an out of date one out back.

[gc45]

Minerat has said it all; we/I an my Son have made quite a few BBQ cookers from propane tanks with narry an issue. We have made three big ones mounted on trailers using 250 gal tanks, several smaller ones using 100 gal tanks..
G

[FLINTNFIRE]

I take off the valve fill with water till it flows out and cut with angle grinder and cutting wheel , smells but is no chance of fire or explosion .

Water will leak out as cutting , no big deal same way I would use a stone cutting blade on skil saw when cutting concrete around old window sills , water keeps the dust down and water keeps it from having any thing to burn.

[baogongmeo]

I trade old tanks in at one of the tank exchange sites. I've asked if they accept old tanks and they've had no problem exchanging them for full ones. Good to have a few extras.
Go to your local hvac repair and see if they have any empty freon tanks you can have. From what I've seen, they are happy to get rid of them.

[georgerkahn]

I've done this but once, and still have 10 each fingers and toes plus two working eyes ! I did exactly as minerat did, 'cept I used a bigger pipe wrench with tank secured to a telephone pole. My only regret was to see I was/am not too adept at grinding/cutting, and the cut tank really had a jagged/saw-tooth magnified appearance. I then magic marked a black circle to grind much of the high spots down, but it still looks like the opposite place to heaven! Hence, if I did another, I'd NOT grind through at all, but have the tank on its side first -- grinding allllmost but not quite through to make a pretty even grind fully around it -- and then, stand it up to finish the grind through.
BEST!
geo

[Rickf1985]

I trade old tanks in at one of the tank exchange sites. I've asked if they accept old tanks and they've had no problem exchanging them for full ones. Good to have a few extras.
Go to your local hvac repair and see if they have any empty freon tanks you can have. From what I've seen, they are happy to get rid of them.

The pot I am using now I made from a Freon tank, The propane tank is larger in diameter so more lead with less height = lower center of gravity on the burner.

[Budzilla 19]

I used to work in a machine/ welding shop, and we always filled tanks, of any kind, to the top with water, then did welding and cutting on them! It could get exciting sometimes when the water level leaked down a little!! Never did have one pop, but a couple did a “ whoofing “ noise! Freon tanks are safer to cut with a grinder, but all ya got is propane tanks, guess ya gotta make do. Be safe.

[BamaNapper]

I got mine from a friend who took care of purging it for me. With the tank still more than half full, he set up a flame source next to the tank and put a rifle round through the top of the tank from a safe distance. I saw the video and it was indeed impressive. The resulting fireball lit the surrounding grass and the tank sat in the flames for a few minutes. When he showed me the video, the first thing I asked was what he was going to do with the tank. It's now my smelting pot.

Maybe not the safest way to purge a 20-lb cylinder, but definitely one of the more entertaining.

[Winger Ed.]

I've done a couple by opening the valve to vent it, remove the valve a day or so later, fill it with water, drain it out,
then cut what needs to be done with a cut off wheel.

I did a 30 gallon one time by venting it, then left it out in the sun for a couple weeks.
Then filled it with compressed air and vented that a few times, then started cutting...
There was no excitement or that 'whooosh' sound either.

[Oaks&Pines]

Lp is heavier than air so if remove the valve and turn the tank upside down any remaining vapors should exit the tank.

[MrWolf]

I cut the top guard off the tank so I can get at the valve. Then take a 12" plumbers wrench with a 4' cheater pipe, strap the tank to a solid fence post and lefty loosy it. They usually break loose, then fill it with water and dawn soap for a couple of days and have at it with a side grinder and cutting wheel.

I did that but I used a Sawzall that cut it like butter.

[JimB..]

I couldn’t get the valve out, it broke, so I slowly drilled a hole with a hose running on that spot and then filled it with dawn and water. Left it a day then flipped it over in the sun for a day, then ran compressed air through it. Cut with a sawzall.

Lots of ways to mark a line on a cylinder. I usually wrap a strip of paper, but can just tape a marker to any outside corner and spin the tank against it.

[zarrinvz24]

Freon tanks will start becoming rarer and rarer over the next few years. New production systems are all going to a propane based (flammable) refrigerant.

[Winger Ed.]

New production systems are all going to a propane based (flammable) refrigerant.

It didn't get hardly any news coverage- for a couple of reasons, but
years back when the price of R-12 went all stupid, some people were charging car AC systems with propane.

[zarrinvz24]

It works great as a refrigerant, but brazing copper line driers and replacing coils are about to be a thing of the past.

[kevin c]

Is the sludge all that flammable? I know it has the odorant smell but I thought left over propane was the problem. Is filling the tank with water and draining it once enough to eliminate the left over propane and any fire/explosion hazard?

[country gent]

I always wash a tank several time with one being a soak. May nit be needed but it makes me feel safer, same with the air hoe blowing into it. I dont care if its a propane sized tank, 55 gallon drum or larger it gets washed out 3-4 times and a good air flow thru while working on it.

On the job or at home there is no need to "Give Blood" when doing a project. Work safe, a little extra time to make sure isnt a big deal in the end.You can also use the wash soak time to build the frame or other need parts so it really isnt wasted time.