Welding with propylene.

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I work at a welding school and because of the recent explosion at the calcium carbide plant we have had to switch from cutting and welding with acetylene to welding and cutting with propylene. Cutting is fine we have the tools for that, it's the welding we are having trouble with. Does anyone know of any tricks or tecniques that make it work better? Are there specific tips or mixing chambers we need to use? Or are we just out of luck?
Reply:Call your specific torch maker direct for tech support, and if it isn't Smith call them too and ask for recommendations.
Reply:Unfortunately I think you are out of luck. To my knowledge you cannot weld with propylene gas. Acetylene provides shielding due to the secondary reaction in the Acetylene flame consuming oxygen in the atmosphere surrounding the weld, with propylene you don't have this effect. My guess is you have a bunch of students getting porosity and pulling their hair out.
Reply:dr87 is correct...shielding problem..
Reply:Acetylene is the only gas that will weld steel effectively.  Modify the program and limit instruction to simple brazing with fuel gas and concentrate on cutting.  I have not heard of anyone requiring a OAW certification in 25 years.  Similarly forge welding is nice to know but for training welders it is good enough to know about it.
Reply:Hmmmm,This sounds familiar. Our CC Welding Lab is having the same issues. I think its going to force some programs that have held onto the OAW class requirements for too long to re-think the practical value of this part of the curriculum. I'm not saying that OAW does not have any value in a college welding program. I'm just suggesting that its role in Certificate and Degree path requirements may need to be reviewed and scaled down. Eric
Reply:One thing some college programs forget is that if you can't walk out of there and pass a welding test than you won't get work. Students don't know what will get them hired, so schools should be straight with them and with THEMSELVES.  IMO dump the OA welding other than mentioning it exists, and use the time for pipe welding which is where the money is.  After you have money you can buy all the gear and train yourself because you'll know puddle control from other processes.Life is a guano sandwich. The more "bread" you have the less guano you'll have to taste!I worked at a welding school ('til State funding dried up) and you cannot underestimate the value of "time under hood" in getting the grads hired. Anything that doesn't put people to work may be fun, but there's time to explore AFTER you are getting paid.As for cutting, the better you get with a torch the less grinding you'll have to do. Perhaps add more demanding torch cutting work?We introduced our students to bevelling plate coupons with a hand torch, then finishing with an angle grinder (9" only, no little grinders). After they got good at it, they truly appreciated precut/pre-beveled coupons and didn't waste them!  Torch cutting is a valuable, time and labor-saving skill.
Reply:There's more to the trade than pipe welding, but I do agree that the schools need to do a better job preparing students for a work environment.