And the warning label says...

Date 08-27-2003 13:15

The standard grade of hose for acetylene is "R"- in order to use alternate fuel gases like propane, natural gas, propylene, etc...you need to use "T" grade hose. the standard grade hose will deteriorate internally if used with alternate fuels. This does take some time, but the result is damaged hose. Any welding supply store should carry or have access to T grade hoses, although the pricing is almost or sometimes more than double than a standard R grade.
have fun...

By bzzzzzzzzzz (**)

Date 08-27-2003 18:08

same with the o-ring on your gas grill regulator assembly. Use a regular o-ring and they will dry rot and crack in short order. for real.

By PhilThomas (**)

Date 08-29-2003 11:20

Well, I *AM* glad that someone is reading this stuff ::chuckle::

I'm not involved much with the cutting part of the industry - but always interested in learning - anyone have an idea what the differences are? What is it about acetylene that makes it need a different grade of hose - and how are the two hoses made to accommodate them?

P

By dee

Date 08-29-2003 12:12

Phil.
I'm no chemist, and cannot answer the questions posted due to lack of specific knowledge. The issue, however, is a bit reversed in your understanding, as I understand it to be... acetylene is an easy gas to hose to the torch, it's the other gasses which cause trouble with the chemistry of the basic hose requirements...

There are enough issues with the molecules involved that I cannot state if there is a problem with the gas dissolving the hose lining, attacking it's flexibility, or whatever without knowing precisely what the two types of hose are made of... providing me with that information will present me with the problem of locating my references, and then finding time to extract the answer. All I can say with confidence in it's accuracy is that it's a hazard to use the wrong hose beause the hose WILL fail.

To extend th ethought, a hose is made up of a lner, a reinforcement cord, and an outer jacket, each selected for desired properties; heat and abrasion resistance, flexibility, tensile strength, and impermeability to the gas it's supposed to conduct. I'd like to avoid the obvious simplistic answer... "the chemistry of the liner is different" and explain pricisely HOW it is, but I cannot. I do not know the chemistry behind the break-down of the plasticising agents in the materials being used, only that it does occur. If the phenomenon of "reduction" is understood by you, it would be a good place to put a bet... I doubt these fuel gasses are oxidizers... if I knew, my answer would be authoritive; it isn't.

The expensive hose will serve for all fuel gasses, the cheap hose only acetylene... but I just read the label carefully and try to save my brain for "real" problems to worry about. There's no accounting for mark-up and prices at the counter... read the label. (on that detail even DuPont would agree)

Regards,
d

By R. Johnson (**)

Date 08-29-2003 12:42

Phil
The only information that I could come up with is that ANSI/ASC Z49.1.94 - Safety in Welding, Cutting and Allied Processes states that oxyfuel gas service hose shall comply with the Rubber Manufacturers Association IP-7 Specification for Rubber Welding Hose. I don't have a copy and their website wanted $30 for a copy :(. So if your curiosity is worth that musch then let the rest of us know what it says :).