OA regs questions

Neither regulator is likely to hook directly to the cylinders you mentioned.

Welding Oxygen looks like it uses a CGA 540 fiting to the cylinder valve but I think (and could be wrong here) that the 75/25 cylinder will have a CGA 580 fitting on it. This difference is intentional.

Propane uses a POL nut fitting, while acetylene is something very different. I would not put propane into an acetylene regulator, even if the nuts were interchangable. Acetylene is just too twitchy to be worth trying that.

I have had a number of regulators rebuilt for about $50 each at a Victor warranty shop.

Good Luck with your surgery, Bob

Thanks, Bob, and all. When you are pondering a pile of newly acquired gear, a lot of things go through your mind as to what will work and what to try.

I attribute this to too much time offshore where you had a 16# hammer and a

36" Stillson, and could fix a watch with them if you had to. You learn to create solutions and think outside the box.

I think I'll just go buy a couple of new bottles, put the regulators on, and try it LIKE IT SHOULD BE DONE IN THE FIRST PLACE.

Finding green lube inside the T handles on the balls leads me to indicate these regulators are new. Even though they were cranked down for a while, I think they probably weren't damaged.

I hate it when idiots think that the solution to an OA problem is to crank down on the handles. I used to release my pressure and unscrew the T handles at the end of every use.

Steve

Steve, Sure, you can use the acetylene regulator on a propane tank. No problem. If you're going to use it for cutting or brazing (it's not hot enough for welding steel) then you'll need to use grade T hoses, because the standard grade R won't handle the propane as well, and are not advised. The fuel regulators are designed to work with multiple fuels. I use Victor regs for oxy/propane cutting all the time.

Can you get another opinion on that from someone experienced,

*please*.

I have a bad feeling that this could be a very bad idea.

Reason - I believe the pressure that an acetylene pressure reducing valve is designed for will be very very much less that for just about all other fuel gases. Hence - if I am correct, you "test" would subject it to a far higher pressure than it is designed for.

The pressure of acetylene in a cylinder is very certainly very low compared to the pressure of propane and just about any other fuel gas. Acetylene is dissolved in acetone in the cylinder. Hence, I hear that the only way you can check how much acetylene is left in an acetylene cylinder is to weigh it and find its mass, as cylinder gauge pressure tells you little... The reason acetylene is stored in this way is that it is too unstable under pressure. Never played around with this, but any amount of warnings will tell you that acetylene spontaneously explodes under pressure. Hence low-pressure storage by dissolution in a solute - the acetone.

Propane is a true gas at all normal temperatures and it is literally compressed into the storage cylinder, going to some very high pressure.

So I do ask - get very clear advice and be certain that I am mistaken in these things I understand to be the case.

Richard Smith

All I want to do is hook it up with propane and 75/25 to pressurize if and make sure the dome loaders are working, and nothing's leaking. I'd get acetylene and oxygen bottles before doing any cutting.

Steve

A sound idea. I will ask at the welding shop. THEY ought to know. As I said, I just want to pressure it up a little and see if things work. (not light a flame, tho)

Steve

Just to point out that I ONLY use Acetylene regulators for Propane, and the local regulator repair shop has no problem with that. In fact they will last long on propane than on acetylene, because propane is cleaner.

The older small tanks and all of the large tanks of Propane have the same valve fitting as Acetylene.

There is NO Problem using an Acetylene regulator for Propane.

The problem with using a C25 (75/25) tank to pressurize a oxygen regulator is that you can't. The connectors are completely different. There is no problem with the pressures as both types of tanks are high pressure tanks that run in the 2000 to 2500 PSI range when full. Also there is nothing in C25 that would damage a oxygen regulator.

Also an Oxygen regulator measures output PRESSURE in PSI, and a C25 regulator measures output FLOW RATE in Cubic Feet per hour.

Thanks, Ernie. I was hoping you would answer.

My main concern was that the T handles were cranked in pretty hard, and I have seen the diaphragms stick in the IN position, or the springs be so weak that they don't work properly.

But seeing that green grease eased my mind quite a bit. That, and the very good appearance of the units in general. Guess I'll just go get some cylinders. I just hate to do that right now because I'm not supposed to be doing any heavy lifting, and I know if I get them, I'll just HAVE to wheel them around and try them out.

And I like the bigger tanks for a shop because they are cheaper to fill, and don't run out in the middle of a job. Just more outlay at first. So, I don't think I'd want to start out with some small tanks, then have to trade out of them soon.

Thanks again, Sensei.

Steve

Thanks Ernie -- I am happy to be stood corrected on this -- Rich. S.

The "green goo" is a definite problem. You will see, "use no oil," on all oxygen regulator gauges. No manufacturer will ever grease an oxygen regulator. Your regulator MUST be cleaned professionally before being pressurized with oxygen.

When you first open the cylinder valve, the abrupt pressurization of the inlet port of the regulator can cause very high temperatures, very much like the compression cycle of a diesel engine. Any combustible material can ignite and explode due to the high temperature and the explosive mix of pure oxygen and even a trace of combustible material. Many welding suppliers have examples of exploded regulators hanging on the wall as a warning.

Do not assume that you can lube the regulator screw and keep the inlet port perfectly clean. It's not something you want to gamble your life on.

awright

Propane turns to liquid at roughly 120psi at normal room temperatures. The safety valve fitted to cylinders in the UK is set to blow of at 150psi.

And a quick google reveals acetylene bottles are at about 250psi.

Richard Smith wrote: (snip)

Actually, not really. It is true that propane's boiling point it -44F (-42C), but in can be condensed into a liquid at higher temperatures that that. The pressure from propane gas is directly proportional to the temperature. Here is a chart:

Vapor Pressures of Propane Temp (F) PSIG (Approx)

-40 3.6

-30 8

-20 13.5

-10 23.3

0 28 10 37 20 47 30 58 40 72 50 86 60 102 70 127 80 140 90 165 100 196 110 220

What this means is that in a tank of propane, you will have liquid, and the headspace will be filled with gaseous propane at the pressure for the listed temperature. 80F will have the headspace at 140PSIG. When you reach the citical temperature for propane though, it can no longer be compressed into a liquid, and the pressure can then go signifigantly higher. The critical temperature and pressure for propane is:

PROPANE CRITICAL PRESSURE

616 psi / 4246 kPa abs

PROPANE CRITICAL TEMPERATURE

206.3F / 96.8C

As other people have mentioned here, there is a pressure release valve that will vent the propane once it exceeds the safe pressure/temperature for the bottle.

"Richard Smith" wrote

This is also very good news for me. I am going to be making a home made Rodenator for gopher warfare, and I already had a Harris propane regulator picked out. Now I can use both of these and won't have to spend a dime.

Ernie, you're a jewel.

Steve

Hot darn. Thanks. I have seen that about a billion times in my life, but didn't add 2 and 2 until you mentioned it.

However, it is on the other side of the diaphragm than where the oxygen flows, and the oxygen should not mix with it.

What say you, Ernie?

Steve

Regulator repair shops have a grease that can be used on Oxygen regulators safely. I don't know if it is green. I'll ask Harold on Monday.

Harold owns "Hansen and Miller", the only torch and regulator repair shop in Seattle, and he is a good freind of mine.. He knows more about them than anybody I have ever met.

"Ernie Leimkuhler" wrote

This is on the ball of the T, and not in or around the hose inlet. To me, that would be isolated from the oxygen by the diaphragm.

Steve

Is there any problem with taking an acetylene regulator that has been running propane and going back to using it for acetylene? Is any claning required?

Thanks, Bob

And am I correct in the thought that you have to use the T style hose for propane because of propane additives?

Steve

No problem switching back and forth, as long as you haven't spewed acetone up into your regulator from the acetylene bottle. The acetone in those bottles is pretty nasty dirty stuff.