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Different kind of problem?

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  • Different kind of problem?

    I'm saying different because I have never seen it before. I called the local weld shop and whoever I spoke to said he never heard of it either, but I don't know how much practical experience he has...

    So, I hate to be the new guy that jumps right in with a question, but I am pressed for time as I can only work outside.

    I borrowed the neighbors cutting outfit. Aside from the tanks being empty, everything looked used but in great shape. Good hoses, good O rings, gauges work...

    I was a tin knocker for 30 years or so, so have a little experience with cutting torches. Both in "shop size" and portable ones.

    My standard, which has always worked well in the past, was about 6lbs acetylene and 30-35lbs Oxygen. But today I have been up and down with both trying to get past my problem. The torch was disassembled, cleaned, soap bubbled... I have no idea what is causing this. And I can't find anything in my searches.
    Here's where you come in.

    I can get a good acetylene flame.
    The second I add O2 it pops and goes out. This is simply holding it. I haven't begun to cut with it.
    I can hear the O2 being added, the flame changes, moves away from the tip, then POP it's out.

    BUT, I can leave the top knob closed, depress the handle and I have a perfect tip. Nice blue points all around 3/16" or so. Perfect.
    Again, with my gauges set differently and different amounts of acetylene being added with the knob... It's driving me nuts. I've never seen this before. I can't add oxygen unless I use the cutting handle and leave the adjustment knob closed.


  • #2
    I would decrease oxygen pressure to about 25 psi and reduce size of acetylene flame before introducing oxygen .....

    I usually find I have to strong of acetylene flame when it "pops" out when introducing oxygen.....

    "Fear The Government That Wants To Take Your Guns" - Thomas Jefferson..


    • #3
      Originally posted by Dale M. View Post
      I would decrease oxygen pressure to about 25 psi and reduce size of acetylene flame before introducing oxygen .....

      I usually find I have to strong of acetylene flame when it "pops" out when introducing oxygen.....

      Been there done that.
      As I mentioned, I tried all sorts of gauge adjustments coupled with all sorts of knob adjustments. I can only introduce O2 with the lever. In which case the tip looks perfect for cutting. And it doesn't seem to matter all that much which way anything is adjusted, as long as it's reasonably close.

      I did manage to cut what I needed to. It took longer to get the metal red hot, and I had to work in baby steps making sure the tip was at the smallest edge so it would heat up enough to get me started, but it sure wasn't working the way it should.

      The weld shop says they have a guy who will rebuild the torch for 67 bucks. Maybe that's what I need done. Although I've used some pretty old and well used torches and never had to send any in to be rebuilt.


      • #4
        Homesteader, First, welcome to the board. Lots of very smart people monitor this board and respond when appropriate. Second, oxyacetylene is old technology. Most people use plasma cutting for curves and complicated cuts and a thin wheel on the 4 1/2" side winder grinder when it is a short, straight cut, so all the fine gradations of operation of the C2H202 are being forgotten. That's why the fellow at the local welding shop didn't know how to deal with this problem. (He was too young to have much use of oxyacetylene technology under his belt.) Third To fix your problem: you have too much acetylene going into the torch before you are adding the oxygen. The gauge readings might not be totally correct (as you said, it's borrowed equipment) so you might want to turn down the regulator just a smidgen. To solve your problem, however, is easy. Don't turn the acetylene valve at the torch on so hard when you are lighting the torch. You do not want the acetylene flame to be jumping away from the tip when you add the oxygen. Otherwise, you will get just the behavior that you described. Note: Once the flame is burning both acetylene and oxygen at the same time and the flame is firmly attached to the end of the tip, if you want, you can add more acetylene to the flame both with the regulator adjustment knob and with the knob on the torch. You can add so much acetylene to the flame that when you turn off the oxygen, the acetylene will be off the end of the tip. That's fine. I surmise that the tip that was installed in your borrowed cutting torch was designed for thin material and was not designed to receive the number of pounds of acetylene that you were giving it when trying to light the torch initially. Also, the tip might need to be cleaned. Also, the potential is that the tip is worn out. However, I'll stick with operator error, just like Dale suggested and to which you reacted poorly. Hang in there, Homesteader, we'll get through this. ~0le
        "If a problem can't be solved, enlarge it." (The 34th president of the United States)


        • #5
          Reacted poorly? Because I had to repeat myself?

          I had the acetylene turned down so low it was on the verge of putting those wisps of soot in the air. Added a little oxy and pop, flame out.
          Like I said, I was all over trying different things, including running at a lot lower and higher pressure just in case it was the gauges.

          And while I did get my parts cut off, I also ordered a new torch for the setup. It came in a couple days after I was done, but at the time I did not think the torch would cut at all. Not for as thick a piece as I had to cut.
          I took off the old torch, put on the new one and everything worked as it should. Nice easy to adjust tip. No problem with the gauges, or the pressure, OR apparently the operator. Obviously a problem with the old torch. Which I imagine is why there's a guy who rebuilds them for $67.

          Plasma cutters have their uses. Especially now that you can get them with built in compressors. That would make them practical for field use.
          But, I still don't think you can heat up a piece of iron cherry red with one


          • #6
            Homesteader, I just went back and reread your original post. OK, it sounds like you know what you're doing. Usually with borrowed equipment, this isn't the case. So you experimented with the pressures and volumes, and the thing didn't work. Then the problem was in the equipment ... just as you found when you replaced it. This is a good board. I don't want to run you off. All best wishes, ~0le
            "If a problem can't be solved, enlarge it." (The 34th president of the United States)


            • #7
              Click image for larger version

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ID:	713109 Normally pops are not caused by too much but too little, it starves and tries to burn back. The larger the tip the more fuel it needs,. Damaged tip seats can be another cause as well as o rings on handles but mostly,,,,,, too little fuel and starving.