How to??? Purge propane tank?

[lwknight]

Has anyone ever tried using a vacuum pump?
A hvac vacuum pump can take the atmosphere down to below 50 microns.
Would that evap the merca-captan stuff?
Its easy enough to build an adapter from the 1/4 flare to the POL.

[hk33ka1]

I have made things out of old propane tanks for years. I also sell and dispense propane. I have used tanks like this for gasoline tanks and oil resevoirs on equipment and more recently casting lead in.

That said doing any of this is at your own risk.


I take the tank and make sure all the liquid propane has been drained or used by an appliance. Then in the shop I secure the tank (let the auto hoist down on it lightly against the floor to hold it) and use a hammer to smash at least one of the collar welds off and peel the collar away from the valve. Then slowly with the valve in a safe direction I remove the valve with a pipe wrench. No gas vents because I fully emptied the tank, but if you didnt it could pop or shoot out. Then I fill the tank up with water, and dump it out at least twice to remove any fumes. Then cut in half with torch, or cut holes and weld new fittings in etc. In doing this I have not had a valve shoot out when removing, or any sparks or special explosions beyond what normally occurs when you cut steel with an oxy/acet torch.

[MT Gianni]

Has anyone ever tried using a vacuum pump?
A hvac vacuum pump can take the atmosphere down to below 50 microns.
Would that evap the merca-captan stuff?
Its easy enough to build an adapter from the 1/4 flare to the POL.

Mercaptan is highly flammable. It will be present in the LP gas at a rate of around 1 drop per 50 lbs. You hopefully will never see enough to get to burn. It will stick in the tank walls and smell but not be a burnable quantity. You need to get the gas out for safety reasons and the odorant out to avoid smelling up everything it comes near..

[a.squibload]

Cut my BBQ-size tank today (10 gal.?), no problems, used cutoff wheel in grinder.
Grinder is double-insulated but I used a borrowed GFI adapter.
Bought the tank for $1 from the propane place, valve was already removed
and don't know how long it had been sitting in the sun.
Filled with water and plugged valve hole but of course as soon as I started cutting
the water went everywhere.
Stood it upright and unplugged the valve hole, cut my higher marked line around the tank.
Once it was split wide open I dumped the water and cut the next line.
(Somebody here cut twice to make a 3" ring to weld to the bottom, for stability, I cut mine the same.)
I figure to use the top piece as an anti-tinsel fairy lid, maybe weld tabs for positioning.