Oxy/Propane questions...

Hello all,

I'm a newbie here, just found the forum last night! I've had some exposure to welding in the past through my Dad and Uncles. However I moved away from home about 12 years ago and am relearning all of it over again, this time properly! :-)

I have a few questions regarding Oxy/Propane. I'm taking a weekend welding class at the local community college, and the instructor there talked about Oxy/Propane last Saturday. I'm looking at getting all set up to do some torch welding/cutting/bending, and have the needed equipment thanks to a generous friend of mine who gave me an older, usable set - minus the tanks of course. I was going to go out and lease a set, but the instructor mentioned that Propane might be the way to go for a home shop like mine. (I'm just a weekend hobbyist...)

I need to buy tips for the old Victor torch my buddy gave me, so replacing tips is not an issue. I know from the little bit of info I found on the net that Oxy/Propane uses more oxygen that Oxy/Acetylene, which is not really a huge deal either, considering the amount I will be using my welding setup. I realise also that Propane burns about 1000f cooler than Acetylene, is this a really big deal - other that longer heat up time and less cutting capability? I probably won't be cutting anything thicker than 1/2 inch, or welding anything thicker than 1/4 inch anyway... What about hooking up to the Propane tank? The instructor claims that I can just use the Acetylene regulator screwed right on to the tank, but I think they are both female thread. Is there some kind of adapter available? Also, how do the pressures compare to those used with traditional Oxy/Acetylene setups - do you just adjust them to the same pressure? Do the gases behave similarly (in terms of lighting the torch and achieving a neutral flame I mean)? How about safety isssues - other than the usual ones present with Acetylene?

I read a bit about it on the net, but haven't really been able to find much specific information anywhere (on the net or in any of the 3 or 4 welding manuals I have...) other than a few people saying they had been using it for years instead of Oxy/Acetylene with no problems.

Sorry I'm rambling on a bit, but any knowledge or resources you might be able to share with me will be greatly appreciated (especially web sites...).

Thanks in advance,
French Canadian

[lotechman]

You cannot weld with propane however it is an ideal fuel for flame cutting and is my favourite.
As for the regulator fitting a standard 20 pound barbeque tank ... yes is is doable. You might not be able to directly connect since some acetylene regulators have different/non compatible connections. You can get an adapter to go from your reg to the propane tank however.

[Franz]

First, since you mention you have an old torch, the hoses should probably be replaced. Older O/A hoses are not rated for use with propane, and it can penetrate some hose materials.
Second, due to the lower temperature, you can't weld with propane. Cutting takes a little longer to preheat and reach cutting temperature. Once you get accustomed to cutting with propane it offers advantages on rusty and multilayered materials.

[lotechman]

You will also have to purchase fuel gas cutting tips. They are of a different construction but most suppliers have them. If you are near a Princess Auto You might be lucky.
The tips need a bit of care since they are two part.
I use similar pressures to acetylene.
You will have to get used to legating up. Turn on your gas then lay the torch on a steel plate. Strike up and the flame till remain near the torch tip. If you don't know this trick you get frustrated lighting up right quick.
It takes a bit to recognize a neutral flame. The feather is not easy to see. If in doubt go lean on the flame. Run the preheats a bit noisy until you gain experience.
You will notice that it take considerably longer to preheat your material before you can cut. The nice thing though is that once your cut has started you will be able to have your torch half an inch off the work and you will not lose the cut.
When operated properly will have no slag hanging under your plate on a cut edge. The cut is significantly cleaner than acetylene

[rusted]

You need 'T' or 'M' rated hose. Most hose is rated 'R' like a good ski movie, or 'RM' which still isn't sufficient.

My Acetylene reg does screw right into my 20lb barbque bottle. Chances are very good that yours does to. There's an easy way to find out. Let us know how you like it.

Besides preheat, it should cut the same as Acetylene since the Oxy does the cutting anyway.

[7mmmag]

I have been using a standard Craftsman (Harris) torch on Propane for 15 or 20 years, with the hoses it came with, with the propane tips, (about $10 to $12 each). It cuts fine. I have never found a propane tank that the regulator would not connect to. The steel I cut does not know the difference between 7500 and 8500 degrees F. A 20 lb propane tank cuts several times longer than an acetylene tank, can be filled on weekends, does not require a lease, and can be robbed off the grill if I need to finish a job at 10 PM on the 4th of July. It is a little harder to light in the wind than acetylene, but you will get the hang of it. With the money you save you can maybe build a shop or at least a wind break.

[Brainfarth]

I'm not sure if I could tell the difference between 7500 and 8500 degrees F.

Originally posted by Brainfarth
I'm not sure if I could tell the difference between 7500 and 8500 degrees F.

LOLOL. Oh, you are the brainy one!

I managed to pass my hand though the flame sometime back around 1970. I was trying to use a long steel rod to flip over the material I was heating & thought I had the torch pointed away from the work but the goggles were restricting my filed of vision, yada yada & the first clue I had was the sizzling sound. A typical OCC stunt indeed, and my hand looked like it was charred. Turned out that I had so much grease on it that did char & looked like hell and even though it smarted pretty good, the damage was minimal.
A friend drove me down to see a young D.O. he knew who looked at it, patted me on the back & gave me an injection of something he said would keep the lymph & other juices flowing to prevent so much tissue loss. I missed a day's work.

[Brainfarth]

I remember running the torch across my palm once. Didn't need a right glove for a few days since my hand turned to leather.

[trackwelder]

I prefer acetylene compared to propane even for my home shop.As far as the ability to fill a tank on the weekend you will run out of oxygen sometime too,and the hardware store doesn't fill them.I keep extra full tanks on hand and never run out in the middle of a project. Good luck with whatever fuel you decide to spark up with.

[Snidley]

FrenchCanadian,

It all depends on your use, and how much you want to spend.

Myself I use propane, but then again I had no intentions of welding with it. I use it strictly for cutting. However, it is hot enough if you want to braze. You can use the same regulators but you will have to change the cutting tips to ones made for propane. Usually under $20.00. The propane will seem to last forever compared to the Oxygen.

[rusted]

I'm thinking about setting up an adapter for my Oxy reg to use disposable oxygen bottles from Lowe's or HD.

[Markopolo]

rusted....now THERE is a lousy idea ! If you're talking about those little red bottles that look like propane cylinders, I believe you could get maybe 10 minutes out of one...and they cost at least a couple bucks apiece !

[Banzaitoyota]

I thought the temp difference between Propane and Acetylene is ~ 400ºF?

I use propane to cut at school and it works just fine. Ripped out a 1/2" custom wrench last thursday.

[lotechman]

I have cut with acetlylene, MAAP, propane and natural gas. My choice is propane. At my presentworksite we use acetylene. I am living with it but don't like it. Getting a nice clean cut freehand is more difficult.

[fishinnutinwis]

I am totally new to cutting, my son has had several classes in school and knows more than I-except he hasnt done any cutting with propane/oxy...we are about to start a project which requires cutting many (35) cow stanchens out of our barn and some old water pipe... the stanchen are about 21/4 water pipe with solid 13/4 - 2 inch rod for strength inserted into them where we are cutting them at concrete floor.. we have a victor torch head... what size tip should we use and at what pressure settings.. I have tried to find this info for the past hr and half looking thru previous posts but cannot find the answers...any help would be appreciated... glenn@woodsnways.com

[7mmmag]

A # 1 oxy/acetylene tip is supposed to cut one inch. A # 2 tip is supposed to cut 2 inches. Seems like I read that an oxy/propane #1 tip cut 7/10 or 3/4 inch. I have never had to cut something thicker, So a #2 NX (Propane tip) should cut 1 1/2 inches. May have to cut it from both sides and whittle it away. I doubt you finding a 3NX without special order. I would start at a 7 lb propane and 40 or 45 lb oxygen. Or you could borrow a Porta-Band band saw.

[farmshop]

I ran acetylene torch cross top of my hand while tyring to keep piece fro tipping over. Trhird degee burn on top of my hand. Wont do that again.

[farmall]

There are plenty of Victor-style and other brand LP tips on Ebay, which is where I get a lot of mine.

If you aren't near a welding supply, tips and hoses can be bought online and I make a habit of checking prices wherever I buy because I'm a cheap bastid.

I like #2 tips for general "cutting up scrap", but you can't go wrong with a 0, a 2, and a 3 as a starting selection. Tips are cheap, so even though I go through very few I keep spares on-hand.

I use and like both propane and acetylene. Propane is more portable and has no slosh or overdraw issues like acetylene.

I ran acetylene torch cross top of my hand while tyring to keep piece fro tipping over. Trhird degee burn on top of my hand. Wont do that again.

GLOVES. Both hands, all the time, every time. If a torch leaks and I'm holding it, I want the delay gloves give me to shut it off.

[kswelderman]

smith torch and propane, then again i dont braze or weld anything with a torch,btw i get about 7 big oxy bottles to a barbq bottle

[weldbead]

Originally Posted by Franz

Second, due to the lower temperature, you can't weld with propane. s.

i thought the problem with welding with propane is that unlike oxy - aceteylene , propane does not provide a shield gas over the weld...

[Stick-man]

If the guy that gave you the equipment had smaller tanks your regulator fitting might look like this. This is a CGA 300 and it will not work with the LP tank..



If so, then you will need to get a new fitting. A CGA 510 which looks like this. And if you'll notice how the CAG 300 nipple is cone shaped vs. rounded like the CGA 510. DO NOT use the cone shaped on an LP tank. It will leak, ALOT.

[7mmmag]

There is no shielding gas with oxy/acetylene or oxy/propane. The shielding comes from the flux - either coated rod or added flux. You can braze fine with oxy/propane. I never could oxy /propane weld very well but I also can't oxy/acetylene weld worth a flip, so it is hard ot tell.

[weldbead]

Originally Posted by 7mmmag

There is no shielding gas with oxy/acetylene or oxy/propane. The shielding comes from the flux - either coated rod or added flux. You can braze fine with oxy/propane. I never could oxy /propane weld very well but I also can't oxy/acetylene weld worth a flip, so it is hard ot tell.

the combustion products are the shielding gas.
and you do not use flux to oa weld....

[7mmmag]

For brazing I use flux or flux/coated rods. My welding book defines brazing as "welding with brass or bronze".