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  #11  
Old 07-02-2011, 11:18 PM
Michael Moore Michael Moore is offline
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I had a chance to try oxy/hyd, and even with a giant "shipyard" torch it seemed more controllable than oxy/acet. The person giving the class hadn't had any luck with oxy/acet and said once he got the o/h his productivity improved a lot. Clearly some people have no problems, and others do, so it may be a personal preference thing. I think that O/H consumes the fuel gas at a much higher rate than O/A.

I've got a capped natural gas outlet in the garage and I keep thinking that if it could be made to work that oxy/NG could be really convenient. But NG is very low pressure. I think there are concentrators for it used for small jewelry torches but I don't know if they'd do a volume sufficient for panel welding.

cheers,
Michael
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  #12  
Old 07-03-2011, 06:42 AM
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satanzhand satanzhand is offline
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They are trying to make it harder to get acetylene her in the UK but to my mind propane is far more dangerous. If one of those cylinders goes off it will take down the building just as easily as an acetylene cylinder. the propane cylinders are much less strong and to my mind much easier to accidentally heat up with the torch or puncture. An acetylene bottle is about an inch thick and as far as I remember from my days of learning welding is designed to go off like a torpedo in the unlikely event that it did go up. We were taught to roll it outside and hose it off if it did have a flashback and start heating from the inside!. A fire is the only way I can see the cylinder becoming hot enough to explode. There is little actual gas in an acetylene cylinder but a lot of pressure. Oxygen is more likely to cause a problem because it will go off if oils is put anywhere near the pressurised parts. I saw a photo of one that had blown its top while being re-filled - it had blown at the neck and it looked like it had been gut with a cutting torch so there must have been molten metal like shrapnel from it I know the guy filling it was injured.

David
There both dangerous. The cops are welcome (well not really) at my place, but the cost is a big big negative over here. Funny story, one of my neighbours many years ago was cutting some pipe then went off to do some gardening and left the torch going on one of the lines...needless to say it turned the barn in to tooth picks and was seen and heard for miles...I've attached a link (pics included) to the local fire station who mounted the bottle on a stand in front of the station..haha looks like modern art..click on the photos its to the left, painted red looking like some type of giant tropical plant

http://111emergency.co.nz/J-M/KumeuFireStn.htm

lol the extra bit to this story is the guy who left the torch going was well known for wearing 50's old lady dresses, hats etc etc while doing the gardening and working in his workshop.. I remember running over there after it happened to find him covered in splinters, sooty face looking shell shocked in his burnt pink flowery dress and Queen Elizabeth hat holding a broken rake.

The point is though propane is good for bending and welding Al...and easy / cheap to get

For got to add you need oxygen/propane mix otherwise it wont get hot enough to weld well
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Last edited by satanzhand; 07-03-2011 at 06:45 AM.
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  #13  
Old 07-03-2011, 07:26 AM
Janne Janne is offline
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I donīt know if this thing is same in gas welding, but on my job, as a metal sprayer, the sulzer metco , HVOF metal spraying equipment, uses propane,hydrogen,and oxygen..when winter comes, and IF inside temperature, on the workroom goes under 18 celsius/64.4 Fahrenheit (cause the big vacuums are used to suck the spraying dust out, and also warm air, so big heaters are on all day)..the PROPANE goes into fluid.This all happens on a 2 meter long hose, from the electric warmed propane outlet from the piping, in to the spraying gun.same thing happens if i forget the hose in contact with the cold concrete floor.or forget the valve open for long break..

Like I said, donīt know does it do that on gas welding, but maybe if you have a cold shop, you could run in to trouble at winter...maybe I am wrong..but still wanted to tell this..
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  #14  
Old 07-06-2011, 10:57 AM
steve.murphy steve.murphy is online now
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Richard,
I havent used a gas fluxer before, but I was under the impression that the post welding/brazing flux residue is less than brushing it on. Is that true?


Thanks

Steve
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  #15  
Old 07-06-2011, 08:47 PM
Richard-S Richard-S is offline
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I don't know anything about gas fluxers; I just brush it on in copious amounts. It comes off easily with hot water and a stainless toothbrush. The only problem areas are in pits, and places I can't get a brush on. If I need to be absolutely certain it's clean I soak it in hot water. I'm thinking about boiling small pieces. I tried muriatic acid but that doesn't seem to do much.
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  #16  
Old 08-19-2011, 07:06 PM
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Scrap maker Scrap maker is offline
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Ok so i have been practicing my gas welding on my .060 3030 and using 1100 rod and have been getting better. My penetration looks good on the backside but somtimes i see what looks like a black line like a crack in the seam. I can blow holes real good!! Ray
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  #17  
Old 08-19-2011, 10:12 PM
bobadame bobadame is offline
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I've practiced a little with oxy/acet. recently. I still need much, much more practice though before I can compare the 2 fuel gasses.
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  #18  
Old 08-20-2011, 03:10 PM
David Gardiner David Gardiner is offline
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Quote:
Originally Posted by Scrap maker View Post
Ok so i have been practicing my gas welding on my .060 3030 and using 1100 rod and have been getting better. My penetration looks good on the backside but somtimes i see what looks like a black line like a crack in the seam. I can blow holes real good!! Ray

Hi Ray, it is normal to get a black line on the penetration, this is the dirt coming through to the surface. If you use some wire wool or scotch bright to clean it it should disappear.

David
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  #19  
Old 08-20-2011, 06:17 PM
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Thanks, Ray
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  #20  
Old 09-30-2011, 06:19 PM
bobadame bobadame is offline
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It's taken a bit longer to get back to this than I thought it would. I have practiced a bit now with oxy/acet welding .060 aluminum. Starting to get the hang of it so I thought I'd try propane. I've nearly worn out a striker trying to keep the torch lit. I'm using a Meco Midget torch with a "00" tip. It blows out no matter what pressure I try to set at the regulator. So I have to conclude that to even try this with propane I'll need a finer regulator. That is probably not going to happen.
What did work: With acetylene: Meco Midget torch with "0" tip. That's .025" diameter orfice. "00", .016" diameter was too cold.

In the past I have used propane to weld platinum with a Smith Little Torch. The orfices in that torch are smaller than my smallest Meco tip. Even so it was always a PIA to set the pressure using propane even with the tiny Smith torch.
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