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O/A Welding Tip?

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  • #16
    Make sure you are using acetylene gas and not propane or MAPP. Acetylene is required for welding, but I suggest using propane for absolutely everything else. The reason is propane is cheaper but will inject far too much hydrogen into the weld leaving it brittle.

    metalmagpie

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    • #17
      Start with a number 1 tip. If the torch pops, go to a smaller tip. Adjust the gas ratio to provide a fuzzy looking cone so that you have a reducing rather than an oxidizing flame. If the weld collapses and you burn holes in the pipe, reduce the heat. I enjoyed welding thin wall tubing and sheet metal with a gas torch. I have worked at learning to gas weld aluminum sheet metal, but I have not yet developed a good technique on that.

      Jim

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      • #18
        I call that a bearded flame. Also when I start the torch I advance the acetylene until the flame leaves the tip. In other words you will see a gap between the tip and the base of the flame. I then back it off until it just returns to the tip and then set the oxy. Another O/A tip is to use a center punch to raise a dimple where you want to pierce through. It give a exposed area to start the burning action.

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        • #19
          Said bearded flame, aka a "neutral" flame is when this fancy named thing called the "stoichiometric ratio" is achieved, exactly the right amount of oxygen to the amount of acetylene (or any other fuel) to react all the acetylene without an excess oxygen (oxidising flame, pale pale blue) or excess fuel, beaded cone and yellow in the flame to the point of floating carbon smut.
          What you get lighting up, big yellow fluffy flame and smuts everywhere.
          Btw turning torches off, oxy first fuel second.
          Mark

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          • #20
            old school ...I always prefer a smaller tip and higher than recommended gas flow...what I call a "hard" flame. less likely to pop back. I learned from a real pro many years ago how to read the "eye" of the weld to know where your fusion/penetration is...... Practice and pay attention to that little slag pool riding on the puddle...you can tell a lot from the way the sparks shoot out of it...when they suddenly start to increase and go straight up you have reached the other side of the metal.....practice.....ox/acet is the most versatile welding critter ever.

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            • #21
              The way I was taught was to light the acetylene, and turn it up till the black smoke JUST dissapears, then turn on the oxy till the cone moves back to the tip. A sharp pointed cone is oxydising, reduce the oxygen and watch the end of the cone change to slightly rounded for neutral flame, and reduce the oxygen a bit more, till you see feathers at the tip of the cone for a carburising flame. If the flame SNAPS out turn off, check the nozzle for partial blockage, clean and repeat. If you need more or less heat, change nozzles. It is when people try to make a small nozzle produce more heat, or a big one to produce less heat that snapping out occurs, unless it is blocked that is! It is all here!
              https://www.boc.com.au/wcsstore/AU_B...nd-Cutting.pdf
              Man who say it cannot be done should not disturb man doing it! https://www.youtube.com/user/philhermetic/videos?

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              • #22
                A good filler rod for non-critical welding is rebar tie wire, easier to find than metal coat hangers.
                North Central Arkansas

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                • #23
                  OK, here's a tip for setting your gas pressures. Your fuel gas is pretty straight forward. Set the pressure to 3 to 4 psi and you are good. Remember that it gets set with the torch flowing gas and not turned off. Unless you have some of those damn expensive dual stage regulators, opening the torch valve will decrease the pressure.

                  Now for the oxygen. This is a bit different, and the reason is that the fuel and o2 pressures need to match but one uses a 15 psi gauge and the other uses a 200 psi gauge. Now if you understand a 200 psi gauge is gonna be within 10% of the full pressure reading of the gauge, guess what, that's more than 4 psi. So setting the gauge at 4 psi (if it will even show that) is not really gonna be right. So a better way needs to be used. Set your fuel gas pressure as mentioned above. Now spin the oxygen regulator pressure clear out. Light the torch and adjust the fuel gas until the flame leaves the end of the tip and then back it off until the flame comes back to the tip. Open the oxygen valve on the torch one full turn and then turn up the regulator until you have a neutral flame. Your pressures are now set. You can adjust your flame size from there. This works on all gas torches equally well.
                  The only other option is to dedicate a regulator to torch welding and replace the gauge for the regulated pressure with a 15 psi gauge.

                  All that being said, flux core MIG wire works dandy in a pinch and has flux in it already, otherwise you will need to use some sort of flux or your welds will become brittle and can be crappy. As far as welding with coat hanger wire... DON"T even try it. You are learning. You have no clue the quality of the wire.... you have no idea what coatings may be on that wire.. Both can ruin an otherwise good weld.

                  Torch welding is a very close cousin to TIG welding. If you can do one, the other is easy. Of course with TIG you are adjusting the heat with the pedal, with a gas torch it's the distance from the puddle and the amount of heat the torch is set to.

                  Also, practice rod manipulation. The way you feed the rod in your hand as you weld. This is a key skill to being a good welder. Watch a couple videos on it then sitting and watching TV practice.

                  One other things that many newbies have problems with. If you are not getting a puddle to form after about 5 seconds of having the flame applied to the metal being welded, the tip is too small or the torch is too cold and needs to be turned up. Bear that in mind. It will save you fighting a weld puddle that you can't seem to maintain.

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                  • #24
                    Originally posted by hermetic View Post
                    The way I was taught was to light the acetylene, and turn it up till the black smoke JUST dissapears, then turn on the oxy till the cone moves back to the tip. A sharp pointed cone is oxydising, reduce the oxygen and watch the end of the cone change to slightly rounded for neutral flame, and reduce the oxygen a bit more, till you see feathers at the tip of the cone for a carburising flame. If the flame SNAPS out turn off, check the nozzle for partial blockage, clean and repeat. If you need more or less heat, change nozzles. It is when people try to make a small nozzle produce more heat, or a big one to produce less heat that snapping out occurs, unless it is blocked that is! It is all here!
                    https://www.boc.com.au/wcsstore/AU_B...nd-Cutting.pdf
                    What I have seen the most common reason for beginners to pop or snap off the flame is to run the torch on way too low setting/power/flow.
                    Location: Helsinki, Finland, Europe

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                    • #25
                      Originally posted by OhioDesperado View Post

                      Now for the oxygen. This is a bit different, and the reason is that the fuel and o2 pressures need to match but one uses a 15 psi gauge and the other uses a 200 psi gauge. Now if you understand a 200 psi gauge is gonna be within 10% of
                      Maybe equal pressure burners are more common on that side of pond but in here injector torches are pretty much "standard" and on those injector torches the o2 pressure is several times bigger than acetylene pressure.
                      0.5 bar and 2.5bar or 7psi and 35psi sound somehow familiar but it has been ages that I have last time even touched gas welding gear.
                      Location: Helsinki, Finland, Europe

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                      • #26
                        Originally posted by itsjames2011 View Post
                        Hello again everybody, another question from the new guy....

                        ...................... Not doing any stainless steel at this point.

                        James
                        Hi James,

                        Hope that you are enjoying the forum! Lots of great advice here.

                        I just want to add one point. I was told at a welding shop that OA welding of stainless is not recommended. I tried it anyway ..................... they were right. I found that because it is oxygen sensitive it forms a scale that contaminates the weld. I did get the two pieces to hold but it looked awful and it wasn't a critical part anyway.
                        Best wishes to ya’ll.

                        Sincerely,

                        Jim

                        "To invent you need a good imagination and a pile of junk" - Thomas Edison

                        "I've always wanted to get a job as a procrastinator but I keep putting off going out to find one so I guess I'll never realize my life's dream. Frustrating!" - Me

                        Location: Bustling N.E. Arizona

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                        • #27
                          Originally posted by fixerdave View Post
                          I haven't seen a steel coat hanger in years... used up the last of my "stock" in the closet a long time ago. I mean, if you actually wanted a metal coat hanger these days, you'd probably have to go buy some welding rod and bend it up yourself Either that, or an antique store. Yeah, not all progress is a good thing, at least for an HSMer.

                          David...
                          If you lived closer by, I could fix you up with a supply of wire coat hangers. They're all my dry cleaner uses and I've got quite a few of them.

                          Sent from my SAMSUNG-SM-G900A using Tapatalk

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