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Acetylene regulator / propane

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RRMBK16/11/2017 12:40:39
135 forum posts
18 photos

Hi All.

Is there any reason that an acetylene regulator cannot be used on a propane cylinder,? the threads and the pressure range is the same. I know about the difference in hose specification but I already have proper propane hoses.

I was wondering really whether it is worth keeping the Acetylene reg as a spare for the propane torch.

MW16/11/2017 12:51:46
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2051 forum posts
51 photos

I would imagine that the gauge suitability is relative to the size of the cylinder, and therefore specific to it's pressure.

Generally speaking, I would've thought it would be okay so long as you know its suitably rated with regards to the pressure.

Michael W

Jeff Dayman16/11/2017 13:56:21
1853 forum posts
45 photos

Do not do this. Regulators for propane and acetylene have springs and diaphragms designed for completely different inlet and outlet gas pressures and are not interchangeable, whether threads will fit or not and regardless of gauge pressures.

You could cause a dangerous high pressure release of flammable gas which could be a major fire risk if you use wrong regulator on wrong gas.

I suggest you ask your local gas supplier for correct regulators for use on their cylinders.

Please don't risk your safety for a few pounds' worth of gas regulating equipment.

Brian Sweeting16/11/2017 15:43:10
437 forum posts
1 photos

Acetylene bottles have left hand threads I'm not sure about propane but would recommend checking.

Nige16/11/2017 15:44:26
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370 forum posts
65 photos

Acetylene cylinder is at about 190 psi at 50 degrees F while Propane is at about 320 psi at about the same temperature. You can see that the Acetylene regulator is working at quite a bit lower pressure with acetylene so it seems likely its regulator is not going to take kindly to 320 psi up its chuff with the possible associated uncontrolled release of all that nasty flammable gas !!!

mark costello 116/11/2017 15:49:59
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599 forum posts
12 photos

My propane cylinder develops 100 psi at rest. I have used a propane cylinder with an Acetylene regulator since way before I found out the caution when the Internet came along. It's been used that way for almost 40 years. Does not seem much of a worry now.

John Reese16/11/2017 16:08:32
845 forum posts
Posted by mark costello 1 on 16/11/2017 15:49:59:

I have used a propane cylinder with an Acetylene regulator since way before I found out the caution when the Internet came along. It's been used that way for almost 40 years. Does not seem much of a worry now.

ME TOO. Maybe 55+ years altogether. I believe my regulators have metal diaphragms.

Nige16/11/2017 16:25:05
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370 forum posts
65 photos

I guess experience will beat theory most of the time

Hacksaw16/11/2017 16:49:17
428 forum posts
173 photos

Me too. In fact I've just been using it... Mine too has been on a 18kg bottle for 25 years and it still ain't empty...or leaking .

SillyOldDuffer16/11/2017 18:06:23
Moderator
6191 forum posts
1345 photos

As an acetylene regulator is designed not to exceed 8 to 10 psi on the output side it will produce less heat than a Propane regulator. Obviously if you don't need the extra heat then the lower output of an acetylene regulator doesn't matter.

Connecting up the other way round is seriously dangerous though: never put a Propane regulator on an acetylene cylinder. It could ruin your day by exploding.

Dave

Nicholas Farr16/11/2017 18:48:47
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2406 forum posts
1188 photos

Hi, I strongly recommend that you do not use any regulator that has not been designed for the gas you are using whether it has been used for 40 odd years or not. All regulators are designed with materials that are suited to the gas that is being used with it, it is not just the pressures you have to concern yourself with. It may well be that you have been using one for 40 or more years without any trouble, but one knock can case a failure you do not want to be near. Regulators have only a guarantee of five years by the manufacturer and this is its life period even if it hasn't been used. One thing you need to think about is, what are the legal consequences if there is a failure and someone was seriously injured or killed. You may not be subject to HSE at work, but you could find that your insurance will not pay out and or be in a court of law if someone is injured or killed by using equipment not designed for it's purpose. Remember fuel gasses are explosive, so please don't get complacent about them.

All fuel gas regulators have a left hand thread for the pipes and connection to their respective cylinder.

Regards Nick.

vintagengineer16/11/2017 20:48:01
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468 forum posts
6 photos

**LINK**

Nick Hulme16/11/2017 22:25:50
743 forum posts
37 photos

And don't run with scissors!

fizzy16/11/2017 23:50:09
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1725 forum posts
116 photos

Or kiss wasps

Hacksaw17/11/2017 00:10:54
428 forum posts
173 photos

Or use a propane torch near a naked flame yes

Russell Eberhardt17/11/2017 07:58:27
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2599 forum posts
85 photos
Posted by Nige on 16/11/2017 15:44:26:

Acetylene cylinder is at about 190 psi at 50 degrees F while Propane is at about 320 psi at about the same temperature.

I think you'll find that is for 50 C. You are very unlikely to be working with your propane cylinder that hot in the U.K.

Russell

vintagengineer17/11/2017 08:42:21
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468 forum posts
6 photos

Propane regulators have a service pressure of 25 bar!

not done it yet17/11/2017 10:13:04
4889 forum posts
20 photos

Propane is at about 320 psi at about the same temperature.

I would rather believe engineering toolbox dot com, which shows about 10Bar at 300K.

Using the correct regulator is a simple enough principle to follow - for safety reasons alone.

Robin17/11/2017 14:59:10
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353 forum posts

IIRC from my school days, acetylene has a bad habit of polymerising in to benzene with a vast release of energy from it's triple carbon bond. To keep it safe they dissolve it in acetone and the acetone is soaked into a something spongy, a bit like soaking nitroglycerine in to kieselguhr. If the tank gets warm of it's own accord you place it gently in the nearest ditch and stand well back. I spent a lot of my childhood throwing calcium carbide down holes in the ground followed by "water" and a match.

That is the sum total of my knowledge of acetylene, what gauge you use is beyond me thinking

Nicholas Farr17/11/2017 17:20:56
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2406 forum posts
1188 photos
Posted by Robin on 17/11/2017 14:59:10:

IIRC from my school days, acetylene has a bad habit of polymerising in to benzene with a vast release of energy from it's triple carbon bond. To keep it safe they dissolve it in acetone and the acetone is soaked into a something spongy, a bit like soaking nitroglycerine in to kieselguhr. If the tank gets warm of it's own accord you place it gently in the nearest ditch and stand well back. I spent a lot of my childhood throwing calcium carbide down holes in the ground followed by "water" and a match.

That is the sum total of my knowledge of acetylene, what gauge you use is beyond me thinking

Hi Robin, I don't know how warm you are taking about, but if it reaches a significantly higher temperature than its ambient temperature, you must not move it at all. In the days gone by, the advice was to move it outside and cool it by putting it into a tank of water or by hosing it down with water. This advice was discontinued at least 15 years ago, maybe even 20, the reason being that it can be detonated by the slightest knock when it is in this state. This was discovered during a fire, when a fireman was moving a hot cylinder by churning it along the floor, but it then came to a small step of less than 50mm and as the cylinder rolled down it, it exploded and of course, killed the fireman. If you ever have a concern about an Acetylene cylinder getting hot, get everybody away from the immediate area and call the fire brigade pronto. Acetylene is the most explosive gas there is, however a Propane explosion will expand too five times its volume. (That's the volume of gas, not the size of the cylinder)

Regards Nick.

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