I made fittings for mine from the hardware store for just a few dollars. Gave up on it, however, due to the smell of residual propane fragrance that I just couldn't get rid of, even after purging. I wasn't too concerned with the pressure issues...just annoyed by the smell.

 

Yeah...I don't know what the correct procedure is for purging, but as the tank was nearly empty, I just opened it up and let the remaining stuff come out (while I was directing a large fan over it). When it went silent, I turned it upside down, and the results were interesting: some foggy blue-gray stuff with a really foul smell came out for about 30 seconds. Anyone know what that would have been?

As far as fittings, I'm tempted to use the original valve on the tank (since it seems to be sealed on. This means, though, that I have to use the same hose fitting, since finding a replacement left-threaded coupler would probably be tough. No big deal, but I'm going to have to drill out the metering hole at the end, since I want my compressed air to flow at more than the 2-3 PSI that propane flows at. Anyone think this is an incredibly stupid idea?

 

I wouldn't drill anything out on the propane tank. My conversion simply screwed into the existing valve and it was under $10.

It took at least 6 fills/purges to get rid of the propane odor. I also left it open outside for the better part of the week.

 

Neither propane or Freon tanks meet ASME specs for an air tank. I have used a Freon tank for years but I need to get rid of it. When I put it in service I pulled a vacuum on the tank and introduced about 1/2 cup of engine oil in to help protect the tank from corrosion. It is still not safe. Air tanks are cheap but they are not as adaptable as the setup I am using. I just need to get one anyway and fix it up.

 

I happened to be at the hardware store yesterday and noticed a fitting there that adapts from the old style tanks left hand thread to a male pipe thread...1/2" I think. It was in the bar-b-que section and is sold as an adapter to an extension hose for about $3.50.
MZIMMERS...I think I know what you're talking about when you're going to drill out the metering hole in the hose coupling. This may be an alternative.

 

This may be a little off but my freind cut a hole in the side of a old freon tank and welded hinges on it for a door and put about a 5 foot stack and heats his deer blind with it.It works pretty good.
Fat 250

 

I'm not talking about drilling ANYTHING on the tank...even I'm not that much of a candidate for a Darwin Award. I'm talking about the coupling that provides the seal to the valve, that's secured by the left-handed nut. It's made of very thick brass, and the end that fits into the valve has a pinhole orifice, presumably to greatly restrict the propane flow. I'm just talking about drilling that out to normal 1/4" NPT width.

I realize that I won't get a lot of pressure out of this tank, or through this fitting, but I'm not trying to run air tools here. Just being able to inflate a soccer ball or two is all I want.

 

nitramjr, I think you're forgetting what keeps the propane in the tank a liquid. Propane in it's natural state is a gas, which is why it wants to be a gas for your grill. If you don't believe me, try a simple experiment with a cheap butane lighter(I know it's not the same chemical but bear with me here).

Drill a small hole in the lighter(a plastic one of course) and see how much liquid comes out. It should all be gas, even though they are filled with liquid butane. The pressure is so great on the gas when the ligher is filled that the butane or propane is forced into the liquid fase. This results in significant pressure for the tank.

As far a pressure goes you're fine using the propane tank, but rust is a serious issue here, as water will be forced out of vapor(gas) phase as it is compressed by your air compressor. This results in liquid water that you may not be able to get rid of in the tank. The liquid water plus the extra air in the tank will actually accelerate rusting inside the tank, and you'll never know it's there.

The oil coating Idea that torque1st thought of seems like a good one to me, because if you can keep it from rusting, there are few compressors that can overload these tanks.

 

You'll get plenty of air out of the OEM opening. I routinely keep mine at 125#'s and use it for filling remote tires, (trailer, truck, bikes, etc). I have a quick release fitting on my tank and can fill the tank in a minute or 2 from the compressor, (80 gallon tank and 6.5 hp). I've been using it for years with no issues. I get rusty water out of my compressor every time I drain the tank, I get very little water when I flip the propane tank over and do a purge. What I do get is clean/clear water, unlike the 10 yr old compressor tank.

 

Well, I went ahead and drilled it out...I just couldn't see getting any meaningful air pressure through a hole that was like 1/32". I expect it to be fine now, and I don't intend to fill it anywhere near 125 PSI...more like half that at most.

mz

 

MZIMMERS, sorry if I sounded like I was accusing you of wanting to drill a hole in the tank. I understand that it was the hose coupling, not the tank you were wanting to drill. In fact, I did the same thing to my coupling in order to get the hole big enough to be useful. It worked just fine, but because of the propane smell, I gave up on it and threw it away.

 

Not arguing with you at all here. Just trying to remember what I "learned" in one of those long ago science classes - either Charles' Law or Boyles' Law or one of them. Pressure, volume and temperature remain proportional somehow, blah, blah, blah....

Any science teachers here that can refresh us?

 

That was most likely residuel ethyl mercaptan, the stink that makes propane smell the way it does. Natural gas (the kind that comes outta the ground for the "smart a**" also has "smell" added so you know it's there.

Ethyl mercaptan in it's undiluted form is REAL stinky. Seems like there was only about a pint or so added to 9,000 gallons in a trailer. It was added as the trailer was being filled.

 

What's wrong with drilling or welding a EMPTY propane tank? I'm sure as long as you purge the tank 2 or 3 times your good to go.

OOOO! Look what I found in this thread:


I cant imagine drilling/welding a propane tank would be anywhere near as dangerous as welding a "GAS" tank!???

 

My Mistake. If I acutally read JENRAL post he's talking about drilling and welding his main AIR tank!

So should I assume drilling or welding a PURGED propane tank is BAD! (LOL)