Propane as an Acetylene Alternative?

[Krunch]

Hey, all,

I just got my first O/A rig. I have never used one before (and still haven't used mine until I get a book to read about how to do it right -- acetylene scares me a little) but I read on another site where a guy claimed that propane was cheaper to use than acetylene for cutting and welding.

He said that you could buy a $30 item and convert the torch to use propane instead of acetylene, and that although it wouldn't put out as much heat as fast, it was perfectly suitable for welding and cutting.

Does anyone know anything about this?

Thanks,

Jeff

[Hotfoot]

Yup. You need the special two piece tip...but its a setup only for cutting, not welding.:p

[PaulChristenson]

No...you need tips designed for propane and should have hoses recommended for propane as well...;)

Read Andy's take on using propane...especially trying to weld 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.

http://www.cousesteel.com/AndysPlace/PropaneAcetylene.html

[ptsideshow]

IT, makes no difference what the person at the LWS, Fleabay WS, or your neighborhood "Legend in their own Mind" tells you, There is no possible way to get a good weld (ferrous) with any thing other than ACETYLENE!

The only reason you can not weld with any fuel gas other then "ACETYLENE" is you can not achieve a "TRUE" neutral flame. Which means you are adding contamination with slightly oxidizing or carburizing flames.

The oxidizing flame, removes carbon form the weld pool changing the metallurgy of the weld. It converts the carbon to carbon dioxide.

The carburizing flame, adds carbon to the weld pool and will change the metallurgy of the weld pool adversely.

Welding means only, joining ferrous metals!

You can braze,solder,silver braze(miss called silver soldering), heat for bending etc and cutting.

As to hoses:
Use only Grade T hose with MAPP,PROPANE PROPYLENE fuel gases.

Use GRADE R,RM,OR T hose with Acetylene.

The make up of the hoses are different and react to the make up of the gases differently.

The biggest differences in the tips is the number, sizes and arrangement of the holes in it. Propane/natural gas tips have smaller and more of them.

The other difference is with an acetylene/oxy flame the hottest part is the inner cone of the flame.

The propane/oxy flame is the outer skirt,(outside skirt of the flame)

Other than that it is only a matter of ease of getting the gases. to refill when the cylinders are empty, or what you have learned on, or have used in the past.

So other than taking a little longer to hit the temperature, If you aren't going to gas weld ferrous materials. It shouldn't be a problem.

http://i35.photobucket.com/albums/d200/ptsideshow/assorted/welding%20books/Propanetips.jpg
This is a scan of a torch booklet on the tips available for that brand. The top tip is for Acetylene, the two below it are for propane and other fuel gas. Heating/cutting tips

:D

[Roger]

Oxy Hydrogen was used to weld Aluminium during WW2 to conserve Acetylene. Gas welding Aluminium requires same flux using O/A or O/H.
Can't weld ferrous metal with Oxy Hydrogen torch.

[moya034]

In my shop, I use propylene for cutting, and acetylene for welding, brazing, soldering. I occasionally use propane for cutting too, usually to use the specialized tips available for propane that I can't get for propylene.

In any event, I'm rambling. Both propane and propylene are excellent fuel gases for cutting. Propylene (the mapp gas alternative) is hotter then propane, and I prefer to use it over propane when possible. Propane will still make a fine cut with a skilled operator.

As other posters mentioned you will also want to get a T - grade hose.

For the reasons ptsideshow mentioned don't even try to weld with propane. I also prefer using acetylene for soldering and brazing as it heats a little faster.

Whenever you invest in a rosebud heating tip get it for propane... much cheaper to operate.

Keep an eye out on craiglist and ebay for used straight cutting torches. I found an ad on craiglist for 3 Victor ST2600FC torches (23" 2 tube injector style) for $15. There were in non-working condition, but for $55 each, my LWS did a beautiful job of refurbishing them.

So anyway my torch setup has the propylene, acetylene, and oxygen cylinders fastened by chain to the wall, with a Y-adapter on the oxygen cylinder. I have one hose for the oxy-aceytlene torch, and another for the oxy-propylene cutting torch. This works out well as I don't have to keep changing hoses and fittings.

Also, you can use your acetylene regulator, with the right adapter for propane, but if I were you get yourself a Victor or Harris torch regulator designed for LPG gasses, which will include both propane and propylene.

[monckywrench]

Keep an eye out on craiglist and ebay for used straight cutting torches. I found an ad on craiglist for 3 Victor ST2600FC torches (23" 2 tube injector style) for $15. There were in non-working condition, but for $55 each, my LWS did a beautiful job of refurbishing them.


Sweet deal! Victor regulators cost about the same to rebuild. It's cheaper than buying the parts online. I grab all I can get for cheap, and thanks to OADoctor on another forum pointing out that Victor 460 series have the same stainless diaphragm and identical compatible seat material (confirmed by downloading the Victor manuals) I use the acetylene versions for both acetylene and propane.

It's so convenient to be able to use any fuel gas that there is no reason not to try them all. Propane has another advantage in that you can bounce the cylinder around in a pickup truck and not worry about spitting acetone. Great for salvage runs with a small oxy bottle.

[Krunch]

Thanks for all the great replies, guys. I appreciate it. I guess I'll stick with acetylene for now...

[Discoman]

you just need some different parts (tips and regulator)
but it is quite cheaper and just as good, unless you need some specific benefits that acetylene offers.
propane is still really good to use.
if you want dirt cheap use a gasoline/oxygen torch. can outperform acetylene in cutting.
more info is here: http://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cutting#Gasoline

[monckywrench]

if you want dirt cheap use a gasoline/oxygen torch. can outperform acetylene in cutting.


Too bad the equipment isn't dirt cheap compared to acetylene or propane.

I've been looking for a Petrogen to play with out of curiosity but they don't come up very often, while a jug o' propane is often free or cheap (I can finally use up the BBQ cylinders I accumulate!) and propane tips are less than fifteen bucks.

I can buy lots of propane for what a Petrogen will cost, won't have to spend it at once, and can swap bottles when I want to cook dinner.

[Discoman]

Too bad the equipment isn't dirt cheap compared to acetylene or propane.

I've been looking for a Petrogen to play with out of curiosity but they don't come up very often, while a jug o' propane is often free or cheap (I can finally use up the BBQ cylinders I accumulate!) and propane tips are less than fifteen bucks.

I can buy lots of propane for what a Petrogen will cost, won't have to spend it at once, and can swap bottles when I want to cook dinner.

luckily most equipment ends up paying for itself
i'll need to find someone i know that has one so i can borrow it to try it out
sure, propane for the cost of a torch, but if you're looking to get a torch, no reason to discount it
you're saying that for the cost of a lot of fuel for an existing torch, you could buy a new torch:confused:(well, that's how all torches are really:) )
well, i'm looking at getting a torch (maybe a Smith heavy duty model)
but i do want to try a petrogen:D

[monckywrench]

In my case, I won't do enough fuel volume to pay for a retail Petrogen in reasonable time compared to alternative uses for the cash such as other equipment which is more empowering.
I'd cheerfully grab one cheap from someone who doesn't like theirs or doesn't use it (that's how I got most of my oxy rigs), but every purchase is a choice between using money for one thing or another, and the Petrogen is a pure scrapping torch. When it's dirt cheap to collect top-of-the-line Victor or Smith gear and rebuild or have it rebuilt as needed, the gas axe is tough to beat for most folks.



well, i'm looking at getting a torch (maybe a Smith heavy duty model)

Smith make some nice gear.
Unless you cut very thick stuff, the Toughcut kit is a great value (about 200 bucks) and VERY well made. (Throw the goggles that come with it in the trash and buy a face shield.) Our welding students haven't ruined any of them yet.

[Nickoli]

The question of Acetylene versus Propane has been debated here before in the past. For years people professed that Acetylene was better for cutting then Propane . While temperature wise Acetylene is hotter than Propane the fact is that they were using Propane for cutting incorrectly. The mistake they make is that they are cutting with Propane like they would cut with Acetylene. It turns out "where" the heat is in the propane preheat flame is not where it is with Acetylene. Propane releases only a small proportion of heat in the inner flame cone ( less than 10% ), so most of the heat in the flame is in located in the outer cone . Acetylene releases almost 40% of its heat in the inner flame cone. If you cut with acetylene you normally put the tip of the inner flame cone on the metal. If you do the same with propane you will be waiting for a long time. If you raise the torch so that the outer flame cone is used the preheat process is started faster . Is it necessarily as fast a preheat as Acetylene, no but it is nowhere as poor as most people think.


In my opinion, I've used both to cut and they get the job done. I tend to use propane because if I run out on a weekend and the LWS is closed I can easily get a refill at many different locations. If you have a 20lb propane bottle, most gas stations will exchange them now-a-days for $20! You will have to throw down just a bit extra cash to buy a two piece propane cutting tip and you need to make sure you have (T) grade hoses. I like using propane because the flame is less likely to pop and soot as does acetylene and there isnt as much worry for fire inside the torch handle!

[moya034]

I took a picture of my torch setup I described earlier for your viewing pleasure (and to show off my really cool setup :D)

Cylinder on the left is propylene, middle is acetylene, and right is oxygen.

There are three torches there, oxy-propylene for the Victor cutting torch, oxy-acetylene for the Harris welding/brazing torch, and air-acetylene for the old Prest-o-lite torch (Inherited that one from my Pop-Pop, it's an OLD torch, but it still works perfectly!).

If I want to use propane for cutting, all I have to do is swap the bottle and cutting tip. If I want to use acetylene for cutting, which is very rare, I'll just screw on my Harris cutting attachment to the welding torch handle. 95% of the time however, I stick with the propylene.

I love the Y adapters... I never have to change fittings no matter what torch I want to use.

I have the cylinders right next to the door so I can bring the cutting torch out into the driveway easily. Also, it's the most logical place in my shop.

http://home.comcast.net/~moya034/pics/torch.jpg

[Sberry]

I used LP for years until we went to plasma. Way cheap and lasts a long time, cant remember changing out a 100# bottle in the shop, probably did, just don't recall. I put Y on the oxy and had 2 torches, a combo on aceyt and cutting on the LP. I used LP on one of my portables, makes for a cheap setup. Still carry it on my regular pickup.

[monckywrench]

Sberry,
If you get bored and feel like making a horizontal cylinder bracket for your truck, one way I saw at a local salvage yard is pretty handy:

Picture a horizontal piece of ~3-inch angle, facing up, bridging the gap between the bed sides with brackets to rest on top of them. Cylinder rests in the "vee". (They used bungees to hold the cylinder because it's a yard truck, and screwed it to the bed rails with sheet metal screws because it's a junker that is never driven fast. That could be done much more securely/nicer. )