I use oxy/propane for cutting, since I have the tanks for the forge anyway. Works fine for me. I still keep acetylene for welding, of course.

Rob: This is the first I have heard of this. I just bought a case of those little yellow cannisters to use for annealing small stuff. It is so easy to just pick up the torch and use it one-handed, that I never thought it might be discontinued. I use propane for my glass work and soldering silver and copper. I use a stick welder or a MIG for steel and stainless. How much MAPP do you regularly use? Nic East,  www.niceastdesign.com

Rob,
I have been wanting a torch for a while but I keep struggling with not wanting acetylene in the barn. Someone had suggested using MAPP (I have a small MAPP torch). When I went to my welding supply place and asked about it they looked at me like I was from outer space. They suggested propylene also. It is hard to find any information on anything except acetylene. My questions are... do you need a torch that is specifically for MAPP or propylene? Do you just use a acetylene torch with some modification for the different gas. What kind of torch do you have? Where do you fine information about these questions?
Thanks, Mele

Rob, in the past years, I have burned many a tank of MAPP, many more of propylene and because of the mindset of todays construction industy,acetylene by the truck load. The conclusion I have had is, actylene, the fast gas. Heats fast, gets used up fast, gets tips dirty fast, and because it self explods at 27.9 lbs in the right conditions, will get you killed fast. Propylene, less heat means waiting a little longer, but still allmost as expensive as act. MAPP,a little colder still, but less cost. The 2 latter gases are propane with added hydrocarbons to make propane burn hotter. There is a couple more brands out there but just propane with the stuff in it so they can mark up the price. Propane and natural gas are about 500 to 600 degrees colder than act. Takes a little longer, but propane is 1/4 the cost of act. and will last 5 times as long, no joke! Big outfits, with lots of thick cutting, use natural gas, but us home town boys have propane. Throw away your tip cleaners,very safe to use, cleaner cuts, less grinding. I am like rick, keep act. for welding or for carborizing the surface of a tool, and ofcourse for filling garbage bags on 4th of july. Did I just say that? Shame on me.

Thanks for the comments, folks. Here is what I know (per my gas distributor and the Victor welding pamphlet) about MAPP vs. acetylene vs. other gasses. Acetylene seems to be unique in the hoses, torches, fittings, regulators, etc. required. My understanding is that MAPP, propylene, propane, and natural gas can all use the same fittings, acetylene uses different hoses, torches, fittings and regulators.
I switched to MAPP from acetylene since I use a rosebud quite a bit and don't want to worry about rate of depletion of the tank, manifolding tanks together, and the general hazard of acetylene.
Rich and Jaybird- I would love to go to propane from my 1000 gal tank I use for my forge, but I don't have a clue as to how to hook it up. I have 20 pounds coming into my shop. I guess I would have to get a larger regulator and bump up the pressure a bit? Otherwise, can I just tap into the line directly, or do I have to jump through other hoops?
-Rob

Rob, I got a 1000 gal. tank with a wet leg so I can fill my smaller cylinders, cost about 350 but tank has to be mt to install. If you got 20 lbs to forge, you have more than enough, even for a big rose bud. Just couple up the right hoses with some flash backs on torch end. Propane will not burn back in torch as act. will, but it look good when the nincompoops from OSHA vist your shop. jay.

Here's a good source of information on these fuel gases.
http://www.weldreality.com/gasdata.htm

The formatting is poor, but the information contained in the page is excellent.

Just so you know, MAPP is Methylacetylene Polypropadiene. It's a mixture of waste chemicals that Dow threw together and sold as a fuel gas. I have seen some small cans of it still available, but if you're buying from a gas distributor and they are selling you "MAPP", they are most likely filling your cylinder with Propylene.

Also, to correct a statement made above, NONE of these gases are made by adding chemicals to Propane. Acetylene (alkyne hydrocarbon), Propylene (alkene hydrocarbon), and Propane (alkene hydrocarbon) are all pure gases (with some impurities in the ppm range.) MAPP is the only mixture covered in this post. When adding chemicals to Propane is mentioned, what is being referred to is "Flamex" (or other trade names). These are all snake oil additives and should not be factored in to your analysis of fuel gas cost and efficiency.

Jason Adam
North Coast Cryogenics