propane or acetylene ?

[Renze]

I have decided to bite the bullet and buy a torch set:

I could get a plasma from 350 euro onwards, but the dealer i regularly buy stuff from, offered me a small professional quality one for 1750 euro, he said he wont sell the cheap ones because he has to attach his good name to anything he sells.
With O/A or O/propane i can also heat, and weld if required.

Propane is cheaper, but cuts rougher ? Is the price difference that big between propane and acetylene consumables ? Can you cut both with one torch ?

 

[AndyMA]

From Wikipedia

"
A propane torch is a tool for burning the flammable gas propane. The maximum adiabatic flame temperature a propane torch can achieve with air is 2268 Kelvin (1995 °C/3623 °F). Some propane torches are also used with a tank of pure oxygen to achieve a flame temperature nearing 3095 Kelvin (2820 °C/5110 °F).
The temperature in these flames is lower due to not total oxygen gain of combustion, heat loss in combustion, oxygen quantity etc.
Propane torches are frequently employed to solder copper water pipes. It can also be used for some low temperature welding applications, as well as for brazing dissimilar metals together.

"Acetylene when combined with oxygen burns at a temperature of 3200 °C to 3500 °C (5800 °F to 6300 °F), highest among commonly used gaseous fuels. As a fuel acetylene's primary disadvantage, in comparison to other fuels, is high cost.""

So as you can see acetylene burns considerably hotter which can be important in both cutting and welding.

Andy

 

[Renze]

But will propane cut ?
Max. flame temperature isnt important when heating, only when cutting.

 

[BigE_]

Yes, propane will cut just fine. Some people prefer it to acetylene. It does take a little longer to start the cut, though.

When I was taking welding classes on the gas welder, we never even bothered with Oxy-Acetylene. We just used Oxy-Propane. I'm sure cost was an issue.

If you are trying to weld with propane as well, you may have to adjust your tip sizes. I've heard it isn't good to switch between propane and acetylene - bad for the hoses. That was long after I've been switching back and forth, though.

 

[smfcpacfp]

First of all it isn't the propane, or acetylene that does the cutting, it is the high pressure oxygen. You can often turn off the burning gas once you are cutting and just use the oxygen (if you are steady). The purpose of the burning gas is get the burning process started just like using a match to start a campfire. Once you have the wood burning all you need is wood and oxygen, you don't need the match. Once you get the steel burning with the torch all you need to add is oxygen.

If you are going to get a torch for cutting I would get the oxy/act setup because of the higher burning temperature as previously mentioned.

I have seen cutting torch setups for propane, but due to the lower temperature you would limited as to what you could cut and it would take longer to raise the metal to the melting point. I am not sure if the propane torch could also be used for acetylene. Why would you want to use a propane setup in any event?

Plasma cutters are great, but much more expensive for a given depth of cut. I would have both if I did a lot of cutting, but I scrape by with a oxy/act setup and a guide holder.

 

[BHD]

I have propane, my son who was working at Scrapping for a number of years soon switched to propane, as well.

the propane in fuel cost is less, it heats good, and one can braze with it, (just need the correct tip, (my son just went the cutting torch route, I bought him to industrial Smith cutting torches off of Ebay brand new, and did not go the interchangeable ends and body, but 98% of what I do is cutting,

YOU CAN NOT WELD with it, you need acetylene to weld with, (steel), but if you have a wire feed I doubt if you will ever miss that possibility,

I think Propane is safer to handle as it will not self ignite if over 15 pounds of pressure, you do not have to be concerned about the with draw rate out of the cylinder, or if the cylinder was on it side,

if you have a propane tank on your property one can add a wet leg and fill your own tanks, (using the bleed off method).
(90% of the propane my son used he never even had to pay for as the farmer would normally let him just refill his tanks out of his farm tank),

I like the Smith set up, yes the hose is different for propane "T" rated, but can be used for both propane or acetylene, where the hose that comes with most sets should only be used for acetylene. to switch from one gas to the other you just change the cutting tip, to the correct one for the fuel your using,

I have both fuels but have all the torches (we have 4 torch sets) on propane, (the tanks are much cheaper as well) a BBQ tank, you can get a special tank that is small diameter and taller but the BBQ tanks work just as well.

 

[BHD]

As far as the heat issue, yes the propane is cooler,

but one thing that throws people off is where the heat is in the flame.

On acetylene the heat is in the flame
On propane it is at the tip or just off the tip of the flame

And if your only experienced with acetylene and using propane you can be disappointed,

but if you hold the tip a little further away there is not that much difference in the actual heat (on propane I oxidize the flame a touch as well and that makes it hotter as well),

below is a very good read about the two flames and cutting with the gasses,

Andys Place, Propane vs Acetylene Cutting

 

[smfcpacfp]

As far as the heat issue, yes the propane is cooler,

but one thing that throws people off is where the heat is in the flame.

On acetylene the heat is in the flame
On propane it is at the tip or just off the tip of the flame

And if your only experienced with acetylene and using propane you can be disappointed,

but if you hold the tip a little further away there is not that much difference in the actual heat (on propane I oxidize the flame a touch as well and that makes it hotter as well),

below is a very good read about the two flames and cutting with the gasses,

Andys Place, Propane vs Acetylene Cutting

Interesting article. I use my torch for welding also, so I guess I will stick with what I have, but for anyone just cutting, propane looks like a good alternative.

 

[BHD]

If I was a scrapper and had the dollars this is the torch set up I would like to try out,
Petrogen | Petrogen Oxy-Gasoline Cutting Systems Home Page
it uses Oxygen and Gasoline, take a look at some of the videos, it is amazing, (yes I know there using a emense amount of oxygen to do some of the cuts, but 20 layers of steel at one time that is dirty, see the sales video, Petrogen | Petrogen Product Information & Training
may be some day,

 

[Renze]

interesting reading!
So the peak temperature of the propane is lower, but there is more energy in a cubic foot, or liter.

The propane doesnt create its own Co2 shield gas so you cant weld with it ? Co2 will occur when something is burning, and thats not the intention when welding...
So when you arent used to anything specific, one can learn torching practice with either gas... In welding class at technical school, they learned us that you have to weld with the tip of the white flame. But thats 10 years ago so i can easily change habits

even if i cant weld with it, i could at least pre-heat heavier steel which are a bit much for my 210A mig.

used sets are more readily available for acetylene, propane i'd have to buy new. is the cost of combustion gas that much lower ?

 

[bobodu]

I figure I can switch to the propane and save a BUNCH of money in the process. I pay about nine bucks a month just for the tank rental and it cost around $60 for a refill of act. We have metered propane service so filling my own tank probably isn't an option but the convenience store a few miles down the road carries exchange bottles 24/7. I'm going with the prpane as soon as I run this bottle dry.

 

[tnhomestead]

I just went propane for the cost. A 20 pound propane tank will last thru 3 125 cu foot Oxygen tanks, and if I need to weld with it,will get a small pony tank. And while propane is cooler, steel melts about 1300 centigrade so it will cut it fine. I think cuts are as clean either way.
Have Fun!!!!

 

[Bird]

But will propane cut ?
Max. flame temperature isnt important when heating, only when cutting.

I think it's like many other things; just depends on how well you learn to do it. When I was a member of our volunteer fire department, our fire chief at the time, who was also a full time farmer, had a propane cutting torch and I've seen him cut 12" diameter thick walled steel pipe and do about as nice a job as I've seen done with acetylene.

 

[BigE_]

I have propane,
YOU CAN NOT WELD with it, you need acetylene to weld with, (steel), but if you have a wire feed I doubt if you will ever miss that possibility,

I guess when I was welding with propane I wasn't really welding, then. I was simply melting the metal into a puddle and adding rod to the puddle. Sure as heck looked like welding, but what do I know? This was cold rolled steel.

 

[J35]

I switched to Propane back in the Mid 80's.

From a practical standpoint the only draw back I ever ran into was lighting the torch when it was windy out, just had to find a small wind block and be quick with the oxygen.

Have fun

 

[BHD]

OK you can heat the metal to melting and melt it together, but there is a scale (oxidation from what I can figure) that forms and weakens the weld and even makes it difficult to get the puddle to flow, (maybe the better statement is one can not make a good, clean, strong, weld with propane) Normaly considered you can not weld with propane.

with acetylene it does not from the scale on the puddle and you get a much cleaner and stronger weld when done.

Andys Place, Propane vs Acetylene Cutting
Welding with Propane
Lots of conjecture out there on why you can't weld with propane. Some say Propane is not hot enough. Actually that has nothing to do with it. Take a #7 Oxygen / Propane tip and compare it to a tiny #1 welding tip. Even though the Propane tip has a far higher BTU output you still will not get a good weld. The reason Propane ( and other alternative fuels ) are not suitable is that when Acetylene is burning with Oxygen it creates a cone of CO2 forming a shielding gas over the weld puddle. Propane does not produce this shielding CO2

 

[Renze]

I just went propane for the cost. A 20 pound propane tank will last thru 3 125 cu foot Oxygen tanks, and if I need to weld with it,will get a small pony tank. And while propane is cooler, steel melts about 1300 centigrade so it will cut it fine. I think cuts are as clean either way.
Have Fun!!!!

I figured you do need a different head for propane than for acetylene, the difference is how much gas is mixed in which location of the torch. they do sell different heads for propane and acetylene, they dont sell welding heads for propane.

I think i should go for propane, and buy new. After watching a co-worker get 3rd degree burn allover his chest and chin, due to a leaking oxygen hose (he unknowingly held the leaky hose against his coveralls, this amount of pure oxygen will make cloth, just as anything combustible, burn like h*ll with just a spark) i dont want to mess around with old hoses, valves and regulators. period.

When i buy a complete set, i'll get acetylene torches which i have no use for when cutting with propane, and only the torch holder can be used in combination with propane torches and tips. I can get the new torch for the price of the set (for which i have no use other than the torch holder)

 

[MotorSeven]

I went with a set of pawn shop torches and changed the tip to propane. The acetylene bottle would have been almost $200. I have already used up one oxy bottle on less than half a bottle of propane & it has cut everything I went after.

RD

 

[towmotor]

Just to weigh in on the actetylene vs. propane:
I've worked where the only fuel gas used was propane. The quality requirement, in terms the "smooth, clean cut" were as stringent as can be found, where any resulting weld repairs would cost thousands of dollars; millions when considered on an annual or per-contract basis.
Suffice it to say that propane will perform adequately to anyone's specifications, where cutting is the primary use.

We also used propane for brazing/silver brazing/silver soldering, but I suspect that the pressures necessary with propane may make it difficult to perform an actual gas weld, where you're forming a puddle and adding a filler-at least to a decent result.

 

[dirt ditch]

I have posted this propane torch link before and it is very informative. Quoting one sentence from the page as to why you can't weld steel with propane:
"When LP gasses burn with oxygen they infuse too much hydrogen into the flame to allow gas welding of steel, and the welds would end up quite brittle."

Welding: Adjusting a heating torch, oxy/propane