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  • cutting with oxy acetylene torch

    can anyone tell we what im doing wrong and how to set up my oxy acetylene rig. All the way from setting my gauges to a good flame for cutting. Every time i cut the cut fills in with the slag. Does that mean im running to hot? How far away should my torch tip be from the metal that im cutting? Im new a this and any information would be helpful. Im mainly cutting mild steel from 3/8" to 1/2".

  • #2
    Originally posted by stretch View Post
    can anyone tell we what im doing wrong and how to set up my oxy acetylene rig. All the way from setting my gauges to a good flame for cutting. Every time i cut the cut fills in with the slag. Does that mean im running to hot? How far away should my torch tip be from the metal that im cutting? Im new a this and any information would be helpful. Im mainly cutting mild steel from 3/8" to 1/2".
    i would say set your oxygen on around 35-40 and keep your acetylene around 12. it sounds like you are too close to the material with the preheat and not enough cutting oxygen. you want your preheat flames around a quarter inch long. when setting the torch, start your acetylene and turn it up until the flame jumps away from the torch head, back it off til it just comes back to the tip. then set your oxygen so the preheat flames are sharp and not feathery. once you get the oxy set, bump the cutting valve and see if the preheat flames jump. you dont want them to change at all from when there is not cutting oxygen to when you have the valve totally open.
    when cutting, keep the preheat flames just so the point of them touches the material you are cutting.
    Hope this helps some
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    • #3
      O/A Cutting

      stretch: I quote from Victor's welding, cutting, & heating guide.

      For 3/8 - 1/2" material

      Tips size "O"

      Oxygen pressure: 25-30/30-35

      Acetylene Pressure: 3-5

      Travel Speed: 18-26/16-22 IPM

      I strongly recommend you use either the manufacture's guide, or look the numbers up on the AWS site. Using O/A requires SAFETY, not guess-work.

      Dave
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      • #4
        Yep what dave posted is correct...also see if you can find someone local to help you out..... and welderdude WTF would you set your acc to 12 ? especially for 3/8"... I do agree with the fact he has too much fuel for the oxy. he is running....so he needs to turn the fuel down not both up....
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        • #5
          Welderdude,

          I think you may want to go back and check those recommendations.

          I've said it before and I'll say it again, you can get as much "bad" advice on the internet as you get "good" advice. Bad information, in my book, is worse than no information.

          Thank goodness there are guys here who really do know what they're talking about.



          Psst. Mike that comment wasn't exactly "politically correct" but, in my book, it was right on the money.

          Dave. Bingo. Hard to dispute Victor.
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          • #6
            O/A Safety, the Sequel

            stretch: How long have you had your O/A set and what brand is it?

            It's very important that you become familiar with all the safety related issues regarding O/A to prevent a small disaster. Hooking a small C-25 bottle to a squirt gun MIG is entirely different than handling O/A.

            Here's some procedures quoted from Victor's Welding & Cutting Guide:

            Always have the cylinders secured on a cart or against a wall.

            Prior to each use, carefully inspect all hoses, fittings for defects.

            Open the acetylene cyl. valve 3/4 and no more than 1 1/2 turns.

            There must always be two "O" rings on the cone end of the welding nozzle, and HAND TIGHTEN only. Using a wrench can damage the "O" rings.

            If you keep the torch connected at all times, the system must be purged after every shut down (when you're done for the day)

            Never ignite the fuel with another open flame (lighter, etc), always use a "striker"

            These are just some of the safety procedures you need to familiarize yourself with. If you have ANY doubts, please have someone qualified show you, according to the book. Learning bad safety habits is only a recipe for a disaster.

            When your garage is a block away, and you're strumming a harp, then it's too late to ask.

            Remember: Safety First

            Dave
            "Bonne journe'e mes amis"

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            • #7
              Stretch,
              If you didn't get a guide with your torch set up here is a down loadable one from Victor. Large file, but it is multilingual. Either download the file or head to your nearest welding supply store and see if they have one available as a hand out. It will cover most every question you may have on care and set-up of your equipment for both cutting and welding.

              http://www.thermadyne.com/IM_Uploads...20guide_lo.pdf
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              • #8
                Originally posted by 84ZMike View Post
                Yep what dave posted is correct...also see if you can find someone local to help you out..... and welderdude WTF would you set your acc to 12 ? especially for 3/8"... I do agree with the fact he has too much fuel for the oxy. he is running....so he needs to turn the fuel down not both up....
                you do realize there is a valve ON the torch body. you dont open it up all the way. and thats just what i set the regulator on for all apps. plus i have over 100' of line and believe it or not there is considerable line drop. if you wanna set your regulator on such low pressure get lingas. plus, each size tip will have the flame jump away at a diff pressure anyway, so its pretty hard to get too much fuel runnin through unless you start both oxy and gas then light it
                Last edited by welderdude402; 02-18-2009, 11:22 AM.
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                • #9
                  Originally posted by stretch View Post
                  can anyone tell we what im doing wrong and how to set up my oxy acetylene rig. All the way from setting my gauges to a good flame for cutting. Every time i cut the cut fills in with the slag. Does that mean im running to hot? How far away should my torch tip be from the metal that im cutting? Im new a this and any information would be helpful. Im mainly cutting mild steel from 3/8" to 1/2".
                  Set guages to mfg spec.

                  turn on acetylene at torch just enought to light

                  turn on oxy, at torch, slow so you don't blow out flame

                  turn up acetylete to point where you will have enough heat

                  adj oxy so you have 3/8 to 1" blue flame from tip (adust to taste)

                  start heat on metal, close but not so close it pops and puts out flame, when puddle forms, ease into blow oxy to start blowing slag away

                  move just fast enough to cut while having a clear path behind. Adjust heat to job.

                  You have to play with it a bit to get the feel, try tilting flame into cut, strait and back, see what works best. Try a lot of heat and other settings.

                  A little practice you will get the feel.

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                  • #10
                    Originally posted by welderdude402 View Post
                    you do realize there is a valve ON the torch body. you dont open it up all the way. and thats just what i set the regulator on for all apps. plus i have over 100' of line and believe it or not there is considerable line drop. if you wanna set your regulator on such low pressure get lingas. plus, each size tip will have the flame jump away at a diff pressure anyway, so its pretty hard to get too much fuel runnin through unless you start both oxy and gas then light it
                    Seriously dude you need to hit the books! And I am not meaning to be condescending in any way...simply trying to convince you how far off base that your advice is without making you believe I am calling you an idiot.
                    Even if you are getting away with dangerous practices you should not recommend them to new people. 12 psi is absolutely on the edge...either your gauges are shot or you are simply uninformed. You can turn the psi up enuff to make BAD things happen. If you have that much line drop then it is time to shorten them or get larger diameter lines. Having your pressures correctly set will make your torch work MUCH better.
                    As far as your flame jumping away and lighting with oxygen already on...that is showing that you seriously would benefit from some FORMAL instruction on how to even use a torch. Once you adjust the torch correctly it won't jump away....if it does you need to re-adjust it
                    I am sure someone can either explain it better or link you to a good video on how to set it correctly. Your friend FK

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                    • #11
                      Thanks, Fusion King

                      I'm glad you chimed in, I was getting tired of typing from my Victor Handbook!

                      There comes a time when I've learned to back off posts.

                      Of all the welding processes out there, I would say the majority of users are either mis-informed or poorly taught regarding O/A.

                      Used properly, it is no more dangerous than driving a car with 30 gal of gas in the tank. Used wrecklessly, they are both a disaster waiting to happen.

                      Some months ago, a fellow member posted some VERY graphic pics of welding accident survivors, and burn victims.

                      As morbid as it may seem, it serves as a reminder to all of us in any trade, to emphasize safe work habits.

                      I watched a guy fall to his death, at the end of the day, (payday no less), becuase he failed to "tie off" one more time. 40 feet later................

                      "There's no excuse for short-cuts, only GRAVE consequences"

                      Dave
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                      • #12
                        Originally posted by FusionKing View Post
                        Seriously dude you need to hit the books! And I am not meaning to be condescending in any way...simply trying to convince you how far off base that your advice is without making you believe I am calling you an idiot.
                        Even if you are getting away with dangerous practices you should not recommend them to new people. 12 psi is absolutely on the edge...either your gauges are shot or you are simply uninformed. You can turn the psi up enuff to make BAD things happen. If you have that much line drop then it is time to shorten them or get larger diameter lines. Having your pressures correctly set will make your torch work MUCH better.
                        As far as your flame jumping away and lighting with oxygen already on...that is showing that you seriously would benefit from some FORMAL instruction on how to even use a torch. Once you adjust the torch correctly it won't jump away....if it does you need to re-adjust it
                        I am sure someone can either explain it better or link you to a good video on how to set it correctly. Your friend FK
                        thanks for putting it nicely, but i read what i typed and it did seem like i meant crank it up and go like ****. i do know the correct ways of setting a torch and my head just thinks faster than i can type.. i was just saying that i always set my reg to around 10-12 cause i adjust the flame from the torch body. in my last post i didnt mean to sound like a "know it all" or whatever. sorry for any misconception.
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                        • #13
                          O/A Pressures

                          welderdude: I think we ALL adjust the flame at the torch body.

                          Unless you're cutting 10"-12" thick material, your acetylene pressure is way too high.

                          There's a reason: TIP & HOSE SIZE is directly correlated to O/A pressures.

                          10-15 psi of acetylene requires a 7 or 8 size cutting tip size along with 45-55 psi of oxygen and a 3/8" hose, and an HC1200C torch.

                          Pressure settings for cutting 3/8 - 1/2" material are based on 25' of 1/4" hose.

                          Let's give our fellow members information based on fact, not fiction.

                          Dave
                          "Bonne journe'e mes amis"

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                          • #14
                            I'll be soon purchasing my first MIG. Took the class and will be mostly making (but not limited to) cooking equipment.
                            I've read enough new welder posts that go something like " I'm new to welding, what machine should I buy?" and the responses are always the same..."what do you intend to weld, how much $ do you have..."

                            Well I'm going to apologize right off the bat because, I'm going to commit the same vague question. I will buy an O/A setup first and do some welding with it, cutting, shaping, learning...

                            No matter which direction I go in once I do get the MIG, I don't want to outgrow the O/A torch/regulator setup. Is there a brand or model that you guys/gals can recommend over the others(Harris, Victor...)? As far as money goes it seems like $500 or less should cover almost everything I've seen, so I'd like to stay in that range (excluding bottle costs). I want something quasi professional.

                            Suggestions please?
                            thanks

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                            • #15
                              i got a smith med duty setup. came with striker, goggles, two tips, rosebud, welding tip and hose and regulators with check valves. i think it was about $350. works well for me. linweld got me a fairly good deal cause i also bought it with the trailblazer and bottles and a bunch of supplies.

                              Edit: also, if you need any info on settings, ill be sure to LOOK IT UP in my smith book before i reply anything
                              Last edited by welderdude402; 02-18-2009, 01:57 PM.
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