I went to a propane cutting torch rather than spending the bucks to get my cylinders straightened out. So far, it is quite different than acetylene, and I am personally not pleased with the results. I have trouble getting the torch adjusted right, and it always seems to be blowing too hard.
Suggestions, please. I have a 0,00,1, and 2 size tip. I fried a couple, as they are more delicate than acet tips.
Which gas, in your opinion is best to use. I'm ready to take the three owner tanks I have over to the dealer and do some swapping now that I've found a reasonable person in the area with regards to owner tanks. The other supplier was as rigid as Mother Superior. I think I can work something out, even if it is to get a in hydro acetylene tank, and have both.
Some basic info as to propane vs. acet, pros and cons would be appreciated so I can make the choice, or use both alternatively as the situation comes up. Already changed to the propane hoses, and they will take either gas.
IIRC, OA is ~1000f hotter than Oxy-Propane (4300 vs. 3300f ???). O-P can give a nicer cut in light or thin material and also claims some (significant?) cost advantage due to cheaper gas and no cylinder costs. O-A suppliers claim increased O2 consumption but YMMV, I do not have (but would like to see) complete comparison test data. Many scrap yards use O-P for (perceived) cost advantage.
O-A is far superior to O-P for cutting thick steel as the cut can be started MUCH quicker. O-A is also superior for heating as it is much hotter and the flame is much easier to direct exactly where needed and it is possible to quickly heat a nut or shrink fit without also heating the bolt or shaft and everything else in the area.
O-P is not suitable for welding steel, and IMHO O-A is superior for brazing, and plain acet is superior for soldering.
Propane is MUCH MUCH safer than acet, (but both need to be handled properly).
First, learn to cut with propane. Those two-piece tips are much much easier to clean. I pick out bits from the preheat grooves and I sand the end flat on the disc sander to get all squared up again and perfectly clean.
When cutting, you want to hold the tip WAY higher above the metal than with O/A. Try it up about 1/2 - 3/4". That alone will make a HUGE difference.
You may need to actually resort to using tip charts, anathema though they are to you who is used to living without them.
Other than that, they cut nearly the same. Once you get used to it.
The main mistake people make with Propane cutting is that they set the torch so it looks like an O/A flame. Wrong. With LP gasses you run a much MUCH LOUDER FLAME!!!!. The flame should be pulled back to a ring of sharp little spikes , and it should be very loud and very pale blue. It looks like an oxidizing flame on O/A, but isn't. I tell my students to try to max out the fuel gas on the torch, and then adjust the oxygen for maximum heat. You can easily see where the best heat balance is by simple parking the lit torch over a piece of steel. As the steel heats play with the oxygen valve. You will quickly see where the maximum heat is.
LP fuels will cut much thicker steel than acetylene because the heat is much further from the tip, and carries further into the kerf.
There is not a single CNC burning table in the US that uses acetylene.
Propane, Natural Gas and LP mixes like Chemtane, and Propylene, rule the big burning shops because it is much more efficient for cutting.
Also because the flame injects so much hydrogen into the slag, any dross stuck to the bottom of the plate chips off easily.
With O/A the flame is more balanced and any dross on the bottom of the cut is more tenacious and malleable.
I can cut faster and cleaner with LP gasses on any steel. Acetylene has one purpose and one purpose only, Gas Welding of steel.
Because the heat is further from the tip with LP, you can cut with the tip 3/4" to 1" above the steel, which means less blow back of dross into the tip, so tips last a lot longer.
And as Grant stated they are much easier to clean. I cleaned 20 of them today, in about 15 minutes.
BTW A trick for lighting LP torches faster with a cross wind is to crack the fuel and the oxygen (about 1/8 valve turn each), hold the torch with the tip resting on a piece of steel at a 45 degree angle. Bring the spark lighter right down near the tip and ignite. The torch will pop to a small flame, then just bring up your fuel and oxygen in stages until you get your LOUD pale flame.
Did you fry the tips because the flame got burning inside or because you got them too hot because you were cutting in a corner surrounded by gussets or something like that? There are one piece propane tips for the latter. Perhaps not for your brand but for oxweld 1515 series probably others. If you have a track cutting device I find there isn't much advantage to acetylene with it. Perhaps a single flame acetylene torch separate to preheat just ahead if you are doing a bevel or to get started if you have enough hoses and other stuff. I also don't see much sense in hand cutting something pretty thick even if the nozzle is rated for it, well unless scrap is the project of the day. If you are cutting round or six sided stock or eight sided stock if such stuff exists the acetylene is superior without a doubt in getting started.
Acetylene is superior for if you loose the cut if you want to use a bulkhead tip or cut off a piece coming 90 degrees off a bar or plate welded on one or both sides. The pre heat for the propane will be very long and probably will need to get it red. you will have to preheat with the acetylene but much less time. for use with a tip with just two preheat holes, usually bent and flat kind of like a big screwdriver which can be washed back and forth and actually get inside the kerf that way to cut out something which doesn't flame cut from a steel surrounding just isn't possible with propane. It is possible to cut cast Iron with acetylene if you really want to have a heavy preheat tip and don't loose the cut. The acetylene tips come more to a point which generally makes them better for cutting off bolt heads and nuts. not to mention the time factor.
propane seems (hand cutting) to me work fine for plate with no heat sucking welds on it in the quarter to half inch range. I generally preheat somewhat. I guess it works fine for angle. At the submarine factory they would not cut until the steel was red and maybe only made six inches or so red at a time. Not sure if that was because of hy80 or the gas they were using. Sure can't fault propane if you get the steel red before hitting the oxygen.
I have this harris cutting attachment model 49 which is designed for low pressure non acetylene gas. With that it doesn't seem necessary to light and then increase both knobs as I do with all of my other acetylene compatible stuff which seems to work with the propane tips. My solution to lighting the thing is to use one of those devices which you hang the torch on and it shuts off the hoses. The weldit one of them you can order a pilot light for propane if you want.
You will notice those scrap yards have liquid oxygen whether they are using mapp or the like or propane. There are some cutting nozzles out there which have really tiny pre heat holes and don't use a whole lot of acetylene, hence no a lot of preheat oxygen.
And some mention the amount of water in the flame which is more way more with propane.
I can lease a cylinder and buy acetylene at $30 a hundred cubic feet at 40 pounds what is that scf or something like that but to exchange the 40 cubic foot tank with the haz mat fee it is like $35. So I got a propane tank and got it filled instead of the lease which costs about that much. Acetylene is better
I just thought of what propane is better for. transferring from one tank to the other. manifolding tanks together
As for the safety isn't acetylene .9 the weigh of air and propane much heavier so it could settle if it leaks so it isn't totally safer in every possible scenario.
Propane is safer due to the lower risk of explosion. You hear about more BLEVE events with propane because it has vastly more marketshare than ACE, but when you look at the statistics, it is safer.
Look at an MSDS for both fuels. Look at the danger of drawing too much ACE from a tank too quickly. Look at the danger of having a fuel gas that has approximately the same weight density as air being able to reach an ignition source at different elevations. You walk into a room with a leaking propane bottle, you have a good chance of walking out. Walk into a room with an ACE cylinder leaking, with it's much lower explosive limit (LEL), and your neighbor grilling on the barby next door could blow your @$$ off.
ACE beats all other fuel gases for its heat input (MAPP came close) and its mix allows you to weld with it. Propane is good for its price, but it takes more gas to cut with, and you cannot weld (soldering and brazing are OK) with it. You can also fill your smaller bottles almost anywhere (or simply swap 'em)
Each of us has a different Risk vs. Benefit equation to look at. Your insurance company may take a dim view of ACE cylinders dotting your workshop, but may not care at all about the propane strapped to your home 5 feet away.
Went to get a tank to convert our rural house to propane as I like it better than electric for cooking. The guy sez that the one I want is a 122 pound, gallon, whatever tank. I ask him about how close it can be to the house. He sez if it is under 125, you can put it right next to the house. Someone was thinking.
I am not arguing the point and for a while they would mail me the msds sheets for the various gasses after I picked up or swapped out cylinders. I was more thinking of walking down the stairway from the area of the leaking propane tank for example. I see the flammability range and make oxy acetylene and oxy propane bombs out of quart oil plastic bottles and toss them into a barrel with a fire. the acetylene one makes more boom.
As for this issue "Look at the danger of drawing too much ACE from a tank too quickly. " The rule is something like for continuous draw one seventh of tank volume for half full tank and room temp. But I don't cut like that. I turn the heat up high to pierce then down to cut a bolt hole and then stop. I know my 40 cubic foot tank is too small for steady state use in the pierce phase but am kind of wondering how it works for the way I and most folks really use it.
You know the rule of thumb, you choose whether or not to follow it. If it don't go boom, no problem. I just hope we don't see a big crater with your mailbox on the edge of it on the 11:00 pm news.
Check out " Adiabatic heating and cooling," also wiki Acetylene and head for the bottom of the wiki page- the section titled "Safety and Handling." Check out the movie at the very bottom of the wiki page, too. I'm gonna watch it tomorrow morning....
For your situation, you're prolly just fine. I would think about watching your guages a little closer if doing longer jobs.
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