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1/8 side + 1/8 other = 1/4 penetration ???

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  • 1/8 side + 1/8 other = 1/4 penetration ???

    I see the machines for alum rated for 1/8.
    If I am welding 1/4 alum bar and do one side 1/8 -
    weld around on the other side for an 1/8 -
    doesn't that equal a one pass 1/4 inch weld on just one side ?
    What is the difference structurally or in practical terms ?

    dumb question - but seriously.
    Thanks, Stu
    Last edited by Stu Miles; 12-18-2012, 03:34 PM.

  • #2
    1/8 one side + 1/8 other side = 1/4 penetration ?

    Maybe I'm looking at this wrong or over complicating it but I don't quite understand the question are you saying welding two 1/8 pieces together to equal 1/4 inch?

    Comment


    • #3
      What kind of machine and what process? You can kind of get away with it on steel, but aluminum is a bit more unforgiving. Because of how conductive aluminum is, it conducts the heat of your weld away very fast, requiring more input amps to keep the heat high enough to weld.

      Comment


      • #4
        Originally posted by Rezeppa View Post
        Maybe I'm looking at this wrong or over complicating it but I don't quite understand the question are you saying welding two 1/8 pieces together to equal 1/4 inch?
        If machine only does 1/8 inch penetration on aluminum,
        and lets say I am welding 1/4 inch aluminum plate.
        I do one side and flip it over -
        is that doing the same thing as one pass with a machine rated for 1/4 inch alum ?

        Thanks, Stu

        Comment


        • #5
          Originally posted by walker View Post
          What kind of machine and what process? You can kind of get away with it on steel, but aluminum is a bit more unforgiving. Because of how conductive aluminum is, it conducts the heat of your weld away very fast, requiring more input amps to keep the heat high enough to weld.
          Well I guess that is why I am asking - cart before the horse maybe -
          because I am try to figure out if I can get away with a smaller machine
          to weld 1/4 inch plate from two sides.
          I am trying to figure out what machine to spend $1000. budget on.
          Realizing I'd have to also get spool gun and Argon with other $.

          Thanks, Stu

          Comment


          • #6
            Depending on what you are welding you could always bevel it. So if it's 1/4" thick grind a bevel leaving a 1/8" land or slightly less & weld it up. This should give you plenty of penetration.

            On another note aluminum bridges easily so it is very easy to have a great looking weld with almost no penetration.
            Last edited by MMW; 12-18-2012, 05:33 PM.

            Comment


            • #7
              thanks

              Originally posted by MMW View Post
              Depending on what you are welding you could always bevel it. So if it's 1/4" thick grind a bevel leaving a 1/8" land or slightly less & weld it up. This should give you plenty of penetration.

              On another note aluminum bridges easily so it is very easy to have a great looking weld with almost no penetration.
              Thanks - That helps - and it helps me understand the purpose a bevel serves.
              Really appreciate the help.
              Stu

              Comment


              • #8
                Bevels, or, i call them weld preps are very important. I do very little aluminum so the other guys can fill you in, but with steel, they are generally used on any thing .250 and up. If you are looking at a machine with a rating of 1/8", and thinking mig, a welder that runs on 110 volts is what to expect. Do your self a favor and dont buy some cheap chinese welder, get one made in the usa

                Comment


                • #9
                  Originally posted by walker View Post
                  Because of how conductive aluminum is, it conducts the heat of your weld away very fast, requiring more input amps to keep the heat high enough to weld.
                  +1

                  Aluminum is almost 5 times more thermally conductive than steel. That means the heat "leaks away" from the puddle into the surrounding metal almost 5 times faster in aluminum than in steel. So it's almost like a race where you're "chasing the heat." To weld aluminum, you need a machine with enough power to dump enough heat into the puddle faster than it can "leak out" into the surrounding metal.

                  If your welder has trouble putting out enough heat to "keep up," you can preheat the surrounding aluminum with a torch before welding, and that will reduce the "chilling effect" that it has on the puddle. Just be careful – unlike a similar-sized piece of steel, the entire piece of aluminum will get hot as heck and stay hot longer than you might expect.

                  In general, for welding aluminum, you want as much horsepower as you can afford.
                  Last edited by Helios; 12-19-2012, 03:36 AM.

                  Comment


                  • #10
                    What machine are you looking at? If you are looking at a 110 mig for aluminum don't waste your time. If the machine is rated for 1/8" steel it will not do 1/8" aluminum very well. Judging by your $1000 budget you are looking at something bigger?

                    Comment


                    • #11
                      Originally posted by Stu Miles View Post
                      If machine only does 1/8 inch penetration on aluminum,
                      and lets say I am welding 1/4 inch aluminum plate.
                      I do one side and flip it over -
                      is that doing the same thing as one pass with a machine rated for 1/4 inch alum ?

                      Thanks, Stu
                      I am curious as to what machine you are thinking gets 1/8 inch penetration on aluminum cause for $1000 you are not going to get a machine that even comes close to that.

                      And when the size of a fillet weld is measured, it is measured from the leg to the toe and the effective throat is what actually means anything.

                      I think you may be misunderstanding the ratings for these machines. When they say 1/4 inch, that means that is the max. thickness of base metal for a single pass weld.
                      Last edited by jpence38; 12-19-2012, 06:36 AM.

                      Comment


                      • #12
                        Your advice is helping my decision

                        Originally posted by MMW View Post
                        What machine are you looking at? If you are looking at a 110 mig for aluminum don't waste your time. If the machine is rated for 1/8" steel it will not do 1/8" aluminum very well. Judging by your $1000 budget you are looking at something bigger?
                        The advice here is a big help.
                        I'm see I need to spend more for machine that can plug into 220 for better penitration.
                        And this characterization makes me understand better -

                        "So it's almost like a race where you're "chasing the heat." To weld aluminum, you need a machine with enough power to dump enough heat into the puddle faster than it can "leak out" into the surrounding metal."

                        So guess I will save a little more money and go for the passport,
                        I'll get a 220 plug into the garage. It's other attributes serve my needs.
                        The stuff I want to do is not really weight bearing and will not have much stress on it. Just making armatures out of 1/4 " bar. I'll start on steel but would like to try aluminum at some point.

                        Thanks for the help,
                        Stu
                        Last edited by Stu Miles; 12-19-2012, 08:24 PM.

                        Comment


                        • #13
                          If these things are not going to be holding hardly any weight you are over thinking this. You are doing a simple butt joint it sounds like, just bevel the weld surfaces and weld them up. Or just take the parts to a local welder and have them weld the pieces you need, it would not cost much.

                          Comment


                          • #14
                            simple butt joint

                            Ya I guess that's the thing - I 'm on a forum where most of the folks
                            really do welding for specific heavy duty needs.

                            My stuff is more hobby related - I attached a photo here of what I am wanting to do - but with aluminum as well as steel.


                            They will be simple butt joints with 1/4 inch bar.
                            But I do want to get into aluminum at some point.
                            If anyone can point me to a tutorial video of a miller passport plus
                            doing aluminum would appreciate. Can't find any on you tube.

                            Thanks, Stu
                            Attached Files

                            Comment

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