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Cuttin' torch setup for thick steel

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  • Cuttin' torch setup for thick steel

    I cut some thick steel today, railroad track actually. I was using a #3 tip with oxygen pressure at 40 psi, and acetylene at 5psi. I had no problem with the foot of the track or the upright portion, but the top rail was a son of a gun! I could get it started okay, but about 1/2" into the cut the molten metal would bubble back into the cut. Once I hit the web in the middle it was near impossible to blow through. I tried both slowing down my cut speed, which got the metal too hot and it flowed back into the cut, and speeding it up, which resulted in losing the cut. I am running about 25' of hose, 3/8" I think, tip was clean, torch was adjusted so the acetylene flame had no soot and was starting to curl and the oxygen was adjusted to a nuetral with the cut valve open. The other oxy valve was full open. How can I improve my cuts on thick steel? I don't do it very often, but my plasma cutter will only cut up to 7/8" so when I cut with a torch it is thick steel.

  • #2
    Try it with a #4 tip at 50psi cutting O2 pressure. The kerf is just a little wider. That may help it clear out. If #3 is all you have, push up the O2 5# and see how it goes.

    Hank
    ...from the Gadget Garage
    Millermatic 210 w/3035, BWE
    Handler 210 w/DP3035
    TA185TSW
    Victor O/A "J" series, SuperRange

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    • #3
      Increase your oxygen to 50 psi.this should help.your tip size and acet.pressure[5 psi] sound good to me.

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      • #4
        I got to thinking about it a little more today, and I don't know if it makes a difference or not but, there are arrestors at the regulators and at the torch ends. Do I need two sets of arrestors or is one sufficient? Also, would the arrestors cause a substantial impediment to the flow, at that high of a flow rate?
        I'll try the higher PSI and let you know. Thanks.

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        • #5
          It does seem like redundant overkill and is probably not neccasary but I dont think they are the problem. A freind of mine has a large torch set up and still uses standard hoses and arresters.
          Trailblazer 302g
          coolmate4
          hf-251d-1
          super s-32p
          you can never know enough

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          • #6
            I am not sure if you would notice a flow restriction with a #3 tip or not, but you may have to set your pressures higher than what you would without the Flashback arrestors. They are definitely very restrictive. For normal cutting though, you should be able to compensate. On really thick material, 6" and up, either high flow flashback arrestors (big bucks), or a torch like the new Smith Dual Guard is the way to go.

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            • #7
              Look 'em over carefully to be sure one set are not check valves. They look a lot alike. If you really have two set of flame arrestors, I'd remove the set at the regulators and put 'em away somewhere for use on your second O/A rog when you get it!!

              Hank
              ...from the Gadget Garage
              Millermatic 210 w/3035, BWE
              Handler 210 w/DP3035
              TA185TSW
              Victor O/A "J" series, SuperRange

              Comment

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