Question for welders

Jan 10, 2004 6 Replies

My son does glassworking with propane and oxygen. He has recently been told that acetelyne hoses gradually develop pin hole leaks when used with propane.



I've cut and brazed with propane and oxygen using regular hoses and have never heard of this, but I'm the amateur's amateur when it comes to welding. Is this a fact or a myth?



Thanks,



Mickey


So don't use acetylene hose !

Acetylene hose is red and usually based on natural rubber. Propane hose is orange and is either made from, or is lined with, a synthetic rubber.

Hose is cheap, regulators are expensive. As well as not trashing his hoses, he should make sure he's not destroying an actylene regulator too.

-- Smert' spamionam

It is fact. There are two types of fuel hose sold for torch use. One is suitable for acetylene only (marked R or RM), the other is for all fuels (marked T). If you have the former, don't use it with propane.

The all fuel hose is a little more expensive than the acetylene only hose, and it is a bit less flexible. Use it if you need to run both propane and acetylene.

Gary

Thank you for a courteous and strightforward answer. Now I wonder if anyone out there can tell me how much use (hours, presumably) it takes to do in a R/Rm hose when using it for propane. Once is too much? Years before problems appear? If I stop now, will I go blind anyway?

Thanks

Mickey

I used propane in an OA hose for some time before I purchased an acetylene bottle. I have been told that the propane will leak through the R/Rm hose, though the amount was unspecified. I do not know whether deterioration will occur nor at what rate.

There are some substances which accompany propane that are not present in acetylene fuel gas - odorant and some paraffin. There could be some risk of the paraffin clogging up the works.

Hmmm, let's see..... My torch hoses are 24 years old, at least, and no signs of propane usage deterioration. Still nice and flexible, so I guess they do fail pretty quickly........

RJ

The damage is cumulative. Propane acts as a solvent for the plasticizer used in type R hose. This causes the hose to become brittle and crack,

*from the inside out*. So you won't see the damage until the hose fails catastrophically.

Type T hose is attacked by ozone and UV, but the damage occurs from the outside in, so a visual inspection will tell you when to replace the hose *before it fails*.

Neither one will fail in a day, probably not in a month, maybe not even in a year. But you'll have no warning before type R hose carrying propane fails. You will have warning before type T hose fails.

Gary

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