Cutting an old propane tank

CharlieTR · Jun 13, 2006

I want to build a sand blaster, and I just came across a trailer load of various sized propane tanks for cheap. I want to buy a skinny long one and cut it one third of it off for a sand tank. Anyone know the best way to clean out an old tank, so it can be torched.

scott_vt · Jun 13, 2006

Charlie,
Your going to have to make sure the tank is empty to begin with. You will have to remove the main valve and then fill tank with soapy water and rinse. I would also try blowing compressed air in the tank to clear it of residual fumes. At that point you should be able to torch cut the tank. This may take some time to rid tank of strong odor!

RobS · Jun 13, 2006

I've heard of using dry ice which will displace the propane and leave non-flammable CO2 as it vaporizes. I'd get a lot more detail before I tried it though /forums/images/graemlins/shocked.gif

Highbeam · Jun 13, 2006

I've removed the valve and then filled it with water to displace the propane. Still stinks though.

Egon · Jun 13, 2006

Steam it.

Egon /forums/images/graemlins/grin.gif

Dex · Jun 13, 2006

Any of these methods will work. Propane is heavier than air so take the valve off and do any of the above methods. Turn it upside down for a day or two and happy cutting.

Hydraman · Jun 13, 2006

The steel of the tank will absorb the ethyl mercaptan
(odorant) right out of the propane. Therefore, even though there is absolutely NO flamable vapors in the tank-- you will still smell the odorant-- forever-- and that is a long time!!
As previously stated--purge, purge, purge first. Fill tank with water-- then drain water out. It's gotta be straight air in the tank now; but it will still stink. Good luck. Don

CharlieTR · Jun 13, 2006

Thanks guys!
Great info.
I think I will not buy a LP tank and make a sand blaster. I will keep looking and maybe find an old compressor tank. I was willing to risk getting blown up, but not that darn stink forever!

Berniep · Jun 13, 2006

Yeah the blowing up part only lasts a little while /forums/images/graemlins/grin.gif

RonR · Jun 14, 2006

I converted an old LP tank to an air bottle about 20 yrs ago.

The air in it STILL smells of propane. I cycled air through it for hours and it still smells.

ron

gary1611 · Jun 14, 2006

Iv'e built a pressurized sandblaster out of a tank it worked very well. The tank was empty for a while then i pulled a vacum used it to capture some r-12. Then it sat i pulled another vacuum on it. Blew some firecrackers up in it. then used a sniffer wich detects gases and there was no traces of propane in it. I did a lot of cutting welding grinding on it. I do not smell propane when i use it. will try to take some pics for you. I know you probaly don't have acess to the EQuipment forementioned but this is how i did it.

bobodu · Jun 14, 2006

I like the firecracker idea! Beats a rag on a stick...
I wouldn't worry to much about the tank after filling with water.But if it still makes you uncomfortable,ya might wanna consider using an electric hot water heater tank.

bendrewjr · Jun 14, 2006

25 yrs ago I made one out of an old water tank (Turned upside down) It will be dipped in the bottom for easy fill (I welded a 2" plug in the bottom) go from there. Drew

Onthesauk · Jun 14, 2006

An old fellow here in the NW cuts the ends off big tanks, welds short legs on them and makes some beautiful backyard firepits. Wonder if that burns the odor out?

Ductape · Jun 18, 2006

I'm going to ask a question while we're on this topic. I have a propane tank i was thinking about making into a lawn roller. I'm guessing the valve is made of brass or some other soft metal (someone spray-bombed my tank, including valve, silver long ago) , so as not be any hazard when threading it out of the top of the tank...... correct ?????

METATEST · Jun 27, 2006

The valve and stem are most likely brass. You should not have any problem if they are. Scrape away at it to see the "gold" metal. The propane can "embed' itself in the metal. Same as a gas tank or hydraulic tank. Filling the tank with water to your cutting line(or just below), will do two things. Dissipate the heat and keep any propane residue nil.
good luck...