cutting with propane and a compressor?

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Ok, so I'm relatively new to welding, mostly mig on some auto projects, but was reading about propane vs acetylene for cutting.I'm about to start another project that has a some semi-decorative cutting involved, probably 1/8 - 1/4". Some of it is pipe so can't use the trusty angle-grinder.  Propane-oxy sounds good, but I don't want an O2 bottle languishing around the shop that I have to move out of the way all the time.I read that the oxy pressure for a cut is ~40psi, my compressor will do that all day. I'm not looking for super precise cuts, actually the more "rustic" the better. Can I hook my compressor up to the hoses and cut away?  I know it's the oxidation that does the actual slicing, but was wondering if %20 (N2/O2 ration in air) was good enough.Lar
Reply:No.Even if you had an oxygen concentrator after that compressor, that could remove the nitrogen, it would still not be pure enough O2 for cutting.
Reply:To my knoledge it won't work. You won't get the propane heat high enough without the O2 to melt the steel. I'd talk to your local supplier about a short term rental. Some welding suppliers will rent tanks short term. The counter guy at my local welding supplier used to do short term rentals even though company policy wasn't really for it. You'd "buy" the new tanks with fills and then he'd refund the difference less the restocking fee, if you brought the tanks back with in 30 days. I do enough business there that they know me by name, even though usually it's just small items. If I need a few extra cylinders for a weekend project, usually they let me take then and just charge me for the gas. I do have an account with them, so if the cylinders don't come back, they'd just roll them on to my lease.Also I can rent complete Oxy fuel cutting rigs from several local rental stores. The rental store prices are not cheap usually, but it's not a bad deal if you only need the torch setup for one quick job. They also rent a small plasma cutter at one location IIRC. Air arc might also be an option if you have a stick welder with enough output, or rent one..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:You need oxygen, not air to cut. Cutting ferrous metals is not melting and blowing away the metal. You heat the metal to its kindling temperature and then introduce a stream of high purity oxygen. The metal actually burns. Done properly and with practice you can actually turn off the fuel gas once the "burning"  has begun (nice for demonstration, not practical).
Reply:Bummer, but thanks for the info. I've been eyeing a plasma so that's probably my best bet in the long run.
Reply:Oxy fuel has it's place and so does Plasma. All depends on the projects you want to do.If I was cutting thin sheet steel Plasma's the way to go if you've got enough to warrant the high price. Nibblers, slitting disks, shears and so on are cheap slow alternatives that can do almost as much as plasma on sheet.Oxy can be used to cut sheet, but you have to be very careful not to over heat the metal. Where it is king is where plasma usually won't help much. Thick steel cutting (compared to small, budget plasmas), heating (removing rusted bolts and bending), soldering/brazing. and with acetylene welding.I use O/A on vehicle work more than my plasma. Usually I've got to cut or heat metal to remove old parts. I won't even bother to brake out the plasma this spring when I have to replace the rear springs and shackles on the truck. I probably won't even bother with the impact wrench. I can almost guarantee that the bolts are rusted to the bushing sleeves and even if the nuts come loose, there's no way I'm saving the bolts after I have to drive them loose. Most likely the bushings are shot by the time I knock out the bolts or cut them any ways. I'll heat and see if the come loose easy, If not I'll just cut the thing apart with the torch and replace it all any ways. The shackle brackets may have to go too from past experience with rust on similar trucks. I'll just wash off the rivets with the torch and be done if so. Usually I can reach in farther with my cutting torch than I can with my plasma. I also don't have to fight trying to get a ground on what I want to cut..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:I'm just a hobbiest, and the price of acetylene is holding me back. I s'pose I could do everything except the welding with propane-oxy. The setup is still cheaper than plasma and I'll have heat to do some metal bending and beating.It's gonna hurt some, but I might have to do a little more thinking about this....
Reply:check craigslist, I see complete rigs with tanks for $300 all the time, heck saw one for $150 a few weeks back. A few months ago I saw one for $30 (with tanks) but I missed it.If you cannot convince them, confuse them.         Harry S Truman
Reply:Get yourself the Oxy/propane setup. If you need to do any welding, see if you can get an acetelyne tank on a short term rental.
Reply:Are the torch sets interchangable between propane and acetylene?  Or is it 2 different torches?
Reply:Originally Posted by akpolarisAre the torch sets interchangable between propane and acetylene?  Or is it 2 different torches?
Reply:You also need a T grade hose for propane.HH 187Miller Bluestar1EAHP AlphaTig 200X
Reply:Different tips & Hose?  How about the regulators
Reply:I just went through this whole process of deciding on propane or Acetylene.  Went Acetylene even though it is more expensive because I am a hobbyist also and doubt if I use one bottle a year AND with little effort I can add the propane parts.  I was told that I'd need a different tip ($20) for cutting with propane, I could use the same regulator, and would need to replace my R hoses with T -- I couldn't talk the dealer into switching the Victor kit hose from the R to T in the deal I made.  The T hoses can be used for either -- why they still make the R's I have no idea.   I think a 20-25 foot T grade hose was something like $30.  I've got the 5 gallon propane bottles around everywhere from the BBQ, Smoker and travel trailer.I went acetylene because I can weld with it even though I have a small mig.  If I change my mind, it will be no trouble to sell the bottle (keep your receipt) and buy the tip and hose.Good luckBob