Old propane tank for compressed air

[Glenn Randle]

I've thought about using an old propane take for holding compressed air for a while. Seemed like an inexpensive solution for getting a huge tank.

Yesterday the gas man was making a delivery and I thought about asking him where I might find a discarded tank. He said he didn't know where they're hauled off to, but the gas company just happened to get one in with a pinhole leak at a bad weld. He said it could easily be patched with a spot weld. I called the manager about it and he said he'd check into it for me and I'll call back next week. Oh btw, it's a 300 gallon.

Anyway, I was wondering if any of you have done this. Seems like an inexpensive upgrade to many air systems. Yes, yes I know...to be sure there's no propane in the tank before welding the leak!

[Dave Bross]

I wouldn't do it.

If the tank ruptures it will have the effect of a large bundle of dynamite. I've know about four deaths in seperate instances from old air compressor or other compressed gas tanks exploding due to internal rust, failed welds, or terminal stupidity like plugging the safety pop-off valve on a liquid oxygen tank.

[Glenn Randle]

Hmmm? I wouldn't have expected an "explosion" from an air leak @ 100-125 psi. Years ago I worked at an Ingerson Rand compressor plant for a few weeks, as temp help. They'd pressure test each unit by pumping it up high & them pulling a plug, it was loud and produced a small ice cube. That's about all I'd think a leak would cause, at the most since a leak would most likely be a much smaller hole.

I wouldn't plan to keep a tank that large inside anyway. But I still wouldn't want a surprise explosion.:eek: Does anyone else think it could/might explode?

[Eben Horton]

why on earth would you need 300 gallons of compressed air??

[Garner Britt]

Glenn,

shouldn't you be working?

If the propane tank is new or close to new and you ALWAYS use a GOOD (ie not Harbor Freight) pressure relief valve set to 125psi or so, I'd see no problems. Those tanks are rated for much higher pressures (400psi or so) and being designed to hold an explosive gas/liquid I'd image they are good to much higher.

Are you thinking of using it for storage or building a monster compressor?

a 300 gallon compressor wouldn't need to run too often...even with heavy use, sandblasting, etc. That's only 10 times the size of mine, oh the envy.

garner

[Tom Littleton]

I've heard that that the Amish sometimes use 1000 gallon propane tanks for air. These are filled when gas or diesel generators are in operation and they have excess capacity. The compressed air is then used to run various tools and equipment.

[Glenn Randle]

Originally posted by Eben Horton
why on earth would you need 300 gallons of compressed air??


That's just a common propane tank size, & it might be free. My oil burner uses compressed air & I've just been running a small Thomas compressor 24/7 without a tank. Hugh said his 80 gallon tank will run his oil burner for many hours before the compressor kicks in. My expen$ive battery backup system recently died, so I'm thinking that a big air tank would be a better alternative than replacing it.

I believe most air compressor tanks are "undersized" because of the economics of shipping costs & material costs of a large tank. In industrial situations ,where air powers many various tools & processes, the use of large pressure tanks is common.

I just figured if the price was "right" it might be handy to have. It would be nice for sandblasting, and other various air tools.

There's probably a special place where old propane tanks are hauled, there is for old oil tanks. But I don't know of them. I just thought this might be a topic worth asking about and something some of you might have done, or might find useful.


& As Garner said, "I'm avoiding work"! One of these days I'll get tired of rice, beans, and PBR!! :wile:

[Alexander Adams]

Air compressors do explode.

A small pin hole leak is a good failure in a compressed air system.

A large rusted area, caused by condensation located on the inside bottom of the tank will resut in a catastrophic event. Often the air lines plumbed with PVC and Copper can fail with a lot of force and can cause injury as well. With enough psi, a air hose failure can cause injury.

Imagine the violent nature of a tire blow out and cut and paste that image with something made of steel. There have been fatalities/injuries over the years caused by compressed ait tanks failing.

http://www.doli.state.mn.us/airtank3.html

http://ncsp.tamu.edu/reports/WorkCover/Alerts.htm

[Victor Chiarizia]

just remember that a used tank will be loaded with stink oil so you may always have propane sented air. vic

[Eben Horton]

AHA. i understand now. :D

[Sky Campbell]

I've used propane tanks with success. Id recommend turning the tank upside down so you have easy access to the valves and a place for a water exit. I also use pvc to plumb a lot of my air system but try to keep it buried or protected. I'm cautious but maybe not always safe.
If your really concerned about it bursting you could always bury it in the ground or just keep it far away from people.

BTW: the propane smell went away fairly quick. We did fill the tank several times with water so we could cut and weld on it.

[Steve Stadelman]

I know that Glenn really wants to put it out in the woods with about 1000 feet of high test hose and run it up to around 500 psi just to "prove" it's good. B.T.W, point the ends away from stuff you like!

[Steve Stadelman]

Just for fun, Google "Kingman Arizona" and "Waverly Tennessee" not just compressed air, interesting though.

[Hugh Jenkins]

I have just set up an air system for another studio using 25 gal propane tanks for air storage. We are using oxygen concentrator compressors with pressure on/off switching added. The tanks have to be taken out of service after 12 years by law and these were in great shape with no rust. We put them out in the sun for a few weeks with the valve open and let them breathe with warming and cooling. Almost no smell left. They are heavy enough wall so that you can drill and tap for a water drain off. (This is not recommended if there is any chance of fuel being left in the tank.) Since these are oiless compressors, it was recommended that we put a few ounces of oil in at the start to coat the tank walls against rusting.

These compressors max out at about 60 to 70 psi so volume is important for storage. This is way less scary to me than the commercial compressor that I bought with 80 gal tank at 175 psi. I have turned it down to 125.

The main reasons for the larger air volume are less compressor cycling (like at night) and being able to ride through a power outage with no loss of burner operation.

[Kraig Richard]

What sux about using a propane tank for air is the stench. My buddy has had one for a long time. It stinks as much now as it did years ago. maybe a newer one w/be cleaner

[Pete VanderLaan]

Captan, the odorant added to propane is manufactured in St Louis and I once visited the factory which smelled like it was going to blow up the entire city. They are not allowed to heat the building with either natural gas or propane because of the masked odor.


As to the tank, at least bury it. Kingman was different in that the contents were flammable and it was a biggie above ground and the tactics used were pretty dumb in hindsight.

I can see wanting a large air supply if you are planning on a Hugh Jenkins style venturi.

[Dave Bross]

The reason they have a mandatory out of service date is because of the rust inside.

I used to cut a lot of them as scrap and I've seen why they pull them from service.

New ones are rather inexpensive if you can get in on the wholesale level.

I guess it's a personal call, based on that 'ol personal risk to reward ratio.

[Glenn Randle]

Originally posted by Dave Bross

New ones are rather inexpensive if you can get in on the wholesale level.




Humm. I'd assumed that they were pricey. That's good to know. If this one doesn't work out I'll check into one.

Btw, where did you get the old ones? Since they're much thicker than oil drums I'd think one might be good for using for a glory, if it wasn't too rusted out. 55 gallon drums work pretty well, and there's not really much metal in a new one of those. I know the ends are rounded, but that wouldn't be too hard to fix.

I know in this age of $20,000 furnaces it's hard to believe some of us still enjoy building our own equipment, and scrounging around for drums. ;)

[Pete VanderLaan]

I wouldn't call them cheap. I think they want over 2.5K for a thousand gallon one up here.

[Jeff Lindsay]

"GOOD (ie not Harbor Freight) pressure relief valve"
The latest Oxymoron
Nothing better than cheep safety parts.
Hey Steve?

[Steve Stadelman]

Hey Jeff?

[Allan Gott]

Straw's cheaper.

Huh.......what were we talking about??????

Oh yeah.........getting tanked.............I dunno..........I got nothin'

[Hugh Jenkins]

I've cut apart many propane tanks and rusting from the inside is not something I have seen. They are pristine inside. Rusted from the outside is very common. Maybe a climate thing. New 25 gallon tanks here run under $100 and are great for air.

Water heater tanks make great glory hole barrels. They are easy to find and come in two inch diameter increments from 14" on up to very large. They have a 10 to 12 guage wall thickness, weld easily and have interesting plumbing and element connections for decoration.

[Kraig Richard]

Originally posted by Hugh Jenkins
I've cut apart many propane tanks and rusting from the inside is not something I have seen. They are pristine inside. Rusted from the outside is very common. Maybe a climate thing. New 25 gallon tanks here run under $100 and are great for air.

Water heater tanks make great glory hole barrels. They are easy to find and come in two inch diameter increments from 14" on up to very large. They have a 10 to 12 guage wall thickness, weld easily and have interesting plumbing and element connections for decoration.

Weld water heater tanks togeather for a culvert pipe. Paint the welds with roofing tar gunk

[Scott Novota]

Very Steam punky of you Hugh.


Scott.
.

[Brody Shaw]

Sky, Hugh, or Dave....when you guys would cut into a tank, what precautions did you use...I have an old 20# that I thought would make a nice small glory....valve is wide open.and shook it up, so its empty.......do you unscrew valve and then fill with water before work? I was thinking either grinding or poss. sawzalling the holes.....whatcha think?

[Scott Novota]

Anybody else just think the reward to pain ratio here is out of wack?


Scott.
.

[Brody Shaw]

for you tube?

[Sky Campbell]

unscrew the valve and fill with water. I use a plasma cutter now a days but I used to use an arc welder turned up and those old damp rods that aren't any good for welding. My glory now is made from an 80 gallon lp tank. They have nice thick walls and there one of the few salvaged tanks I can find that aren't galvanized.

[Brody Shaw]

Thank you Sky.......

thats what I thought......