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Thread: cost of cutting

  1. #11
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    I wondered because the flame never changed, just the Oxy flow increased.
    Retired - Journeyman Refrigeration Pipefitter - Master Electrician - Fine Line Automation CNC 4x4 Router

  2. #12
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    Quote Originally Posted by danlb View Post
    It appears that I was wrong. Sorry about that. I was told by the instructor that when the "blast" lever was activated the acetylene flow was interrupted and it reignited when the oxy blast lever was released. It made sense at the time since the burning steel was hot enough to burn in the oxygen flow.

    In retrospect, without the acetylene for a pilot light you'd waste a lot of time relighting each time the cut faltered.

    Dan
    It's possible to continue a cut with oxy alone since as said above once the oxygen jet starts the metal becomes the fuel but it's just not practicable especially so if cutting by hand.
    Peter - novice home machinist, modern motorcycle enthusiast.

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  3. #13
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    Yes it is theoretically possible to cut steel using oxygen alone once the preheat has warmed up the metal and the cut has been initiated, actually saw it done once with a hand torch. In actual use though it is far from practical. I always make a habit of having one of the preheat orifices in line with the direction of the cut whenever possible.
    Hard to imagines an "instructor" actually making a statement like that insofar as how the cutting torch functions, good grief. Makes you wonder what other gems he's passed on over the years.

    Oxygen lance cutting is a different animal all together. The lance contains iron rods that are lit using a torch to initiate the burning of the rods which are then fed straight oxygen, sometimes the lance itself is lit, the lance is then used to cut very large sections of steel. The lance is a consumable if you will.
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  4. #14
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    I think the oxygen lance contains aluminum rods if I remember correctly.

  5. #15
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    Quote Originally Posted by garyhlucas View Post
    I think the oxygen lance contains aluminum rods if I remember correctly.
    The ones I've seen didn't but yes you're right they do sometimes contain aluminum rods as well.

    https://en.wikipedia.org/wiki/Thermal_lance

    A thermal lance, thermic lance, oxygen lance, or burning bar is a tool that heats and melts steel in the presence of pressurized oxygen to create the very high temperatures required for cutting. It consists of a long steel tube packed with alloy steel rods, sometimes mixed with aluminium rods to increase the heat output. One end of the tube is placed in a holder and oxygen is fed through the tube.
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  6. #16
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    Plasma is pretty cheap but a good machine will be so expensive that you could probably buy a life time of acetylene for the cost of Red or Blue. That's what has kept me from buying one until a month ago. I went ahead and took a risk on one of those $200 Chinese ones. The first one I got didn't work well so I called the vendor, who is in the US , and complained. He sent me another one and I got it 2 days later. It works surprisingly well. I can't speak for longevity yet, so time will tell. I'm kind of hoping I can give up my tank lease. They just doubled the price this year.

  7. #17
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    Quote Originally Posted by dian View Post
    can anybody estimate the cost of an acetylene cut? e.g you make a cut 10" long in 1/2" steel? (gasses only.)
    Less that 15 min
    Note there is clean up add 20 min

    Dave

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  8. #18
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    Quote Originally Posted by fig View Post
    Plasma is pretty cheap but a good machine will be so expensive that you could probably buy a life time of acetylene for the cost of Red or Blue. That's what has kept me from buying one until a month ago. I went ahead and took a risk on one of those $200 Chinese ones. The first one I got didn't work well so I called the vendor, who is in the US , and complained. He sent me another one and I got it 2 days later. It works surprisingly well. I can't speak for longevity yet, so time will tell. I'm kind of hoping I can give up my tank lease. They just doubled the price this year.
    I have had good luck with Longevity brand plasma cutters and I hear good things about the Harbor Freight one. I sold my Oxy-Acetylene outfit years ago. The price of gas has gone out of sight here. Unless your the John Deere plant or the same purchasing vast quantity's at a time. Plasma is much more cheaper to use. Actually a small angle grinder with metal cut off disk works pretty well for the straight cuts.
    Retired - Journeyman Refrigeration Pipefitter - Master Electrician - Fine Line Automation CNC 4x4 Router

  9. #19
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    I used O/A in school for cutting and welding.

    I never bought an O/A setup. I instead got a plasma and never looked back. The only thing I feel I could benefit from O/A is heating stuff. That isn't enough for me to have it around. Its funny to because we already have like 10 tanks for oxygen around for the bait business.
    Andy

  10. #20
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    Andy have you thought about using propane in conjunction with the oxygen? As you say it comes in darn handy as a quick source of heat for a number of applications, also darn handy for use in brazing and silver soldering.

    I used to use an O/A torch setup a lot for cutting metal then switched to propane to cut costs. However I can't remember using to cut metal for a long time. Between plasma, air and angle grinder zip wheels, and a cordless Sawzall I just can't think of a good reason why I need the cutting torch very often.
    Home, down in the valley behind the Red Angus
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