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  • Aluminum brazing vs. welding

    So my buddy who is a highly skilled tig welder just had a salesman from www.muggyweld.com stop by his shop to demo their brazing rods. He said he was totally blown away at how easy the stuff was to use, how well it worked on dirty material, etc. He also said the sales guy claimed that two pieces of aluminum brazed together with their rod would be much stronger than those same two pieces being tig welded together with conventional tig rod.

    Is this really true? If you are building something structural out of aluminum is it actually stronger to braze it than weld it?? Maybe I've just had my head in my you-know-what for my whole life, but I always thought good welds were stronger than the base material itself. I guess I'll just be a little disappointed that I just spent $$$ on a Dynasty 300 when all I really needed was a blue propane torch from Home Depot

    I'd love to hear any discussion on this in terms of concrete facts, e.g. tensile strengths, etc. I guess I'm just a bit skeptical at this point!

    Thanks,
    Jeff

  • #2
    In the case of thin material and lap joints it probably is since there is much more area connected, but otherwise i would say NO.
    Dynasty 200 DX
    Millermatic 175
    Spectrum 375
    All kinds of Smith OA gear

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    • #3
      Originally posted by 2JZfan
      So my buddy who is a highly skilled tig welder just had a salesman from www.muggyweld.com stop by his shop to demo their brazing rods. He said he was totally blown away at how easy the stuff was to use, how well it worked on dirty material, etc. He also said the sales guy claimed that two pieces of aluminum brazed together with their rod would be much stronger than those same two pieces being tig welded together with conventional tig rod.

      Is this really true? If you are building something structural out of aluminum is it actually stronger to braze it than weld it?? Maybe I've just had my head in my you-know-what for my whole life, but I always thought good welds were stronger than the base material itself. I guess I'll just be a little disappointed that I just spent $$$ on a Dynasty 300 when all I really needed was a blue propane torch from Home Depot

      I'd love to hear any discussion on this in terms of concrete facts, e.g. tensile strengths, etc. I guess I'm just a bit skeptical at this point!

      Thanks,
      Jeff

      In some ways it is stronger. The lower temps do not hurt the strength of base metal as much as the higher interpass temps seen from tig/mig.

      It depends on the application.

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      • #4
        A properly brazed joint joins the two pieces at every point where they overlap. Whereas the TIG joint may only be on the surface and down to the level of the penetration of the machine. So, as mentioned, it all depends in the sizes of the pieces being joined and the joint design.

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        • #5
          Ok, let's go to the other extreme. What is a specific application where welding is stronger/better? I feel like I'm missing something here. If Tig takes more skill, more expensive equipment, and results in a weaker (or at least not any stronger) part, then why do people weld aluminum?

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          • #6
            Originally posted by 2JZfan
            then why do people weld aluminum?
            I would for cosmetic reasons.

            Brazing would be fantastic for most of the work I do on stainless -- it would warp less, joints would still be strong enough, etc -- but you can't grind a braze flat and it has that funky yellow color...

            So, it gets Tigged. I don't do a lot of Alum, but would weld it instead for just the same reason.
            BigDTig, Dallas, Texas
            Miller Dynasty 200DX
            Coolmate III Cooler
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            • #7
              Welding would be a lot faster. Joint design is less critical as are the joint tolerances. Good question.

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              • #8
                i watched a few videos on their website, prety interesting stuff, i could see uses for it in some situations.......you'll still never catch me trading off my Syncrowave any time soon.
                The one that dies with the most tools wins

                If it's worth having, it's worth working for

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                • #9
                  Originally posted by 2JZfan
                  Ok, let's go to the other extreme. What is a specific application where welding is stronger/better? I feel like I'm missing something here. If Tig takes more skill, more expensive equipment, and results in a weaker (or at least not any stronger) part, then why do people weld aluminum?
                  It seems to me that it would be very impractical to braze anything very large, the amount of time it would take to heat a large weldment of aluminum to 600 degrees would not be practical, It is also unclear if this brazing rod fills with capillary action (brazing), or is it braze welding where the base metal is brought up to tinning temperature and a bead is deposited over the seam with the filler rod? I also wonder if this rod can be used in any position but flat.

                  This rod is also VERY expensive if used more than occasionally $49.00 + $7.00 shipping for 7-18" rods ($.44 per inch of rod). I could not find any spec about how much weld you could expect from 1 rod.


                  I frequently braze aluminum and steel tubing together and in my experience the temperature is very critical and the parts have to be VERY clean. the rod we use is JW Harris AL-braze and AL-solder500. There is nothing fun about it. (in my opinion). I must admit I have never tried to braze anything other than tubing connections.


                  Another reason we weld instead of braze is the low melting point of aluminum brazing about 600-800 degrees.

                  What I don't understand is if this stuff is so great why won't they give small samples (10" rods or something)

                  I wish one of you guys would by some and let us know if it is the GREATEST THING!

                  Just my Rambling opinions

                  Bruce

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                  • #10
                    I've been brazing aluminum for years and my customers do think it's the greatest thing. I use eutectic, muggy, and hts2000 and of the three I really like hts2000. Brazing and welding are really different processes, Tigman posted about fixing his aluminum radiator useing his syncrowave, if he brought that job to my shop I would have brazed it, it's quicker, easier and very effective, I've repaired hundreds of radiators, condensors, oil coolers, you name it, useing aluminum braze.

                    A customer brought me a late model a/c condensor last week, he hit a critter and poked a hole in it, no after market unit available yet, dealer wanted $700.00 for a new one and a week away, I fixed it in 10 minutes with hts2000, needless to say he was a happy camper.

                    I've used my syncrowave with all 3 rods but it's just easier to grab the torch.

                    Eutectic and muggy super alloy 5 both need flux(or argon) to flow, hts2000 does not, maybe that's what I like about it, all three will do the job.

                    Like I said before, I think the two processes are quite different, I would not want to be left with only one or the other, I need 'em both.

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                    • #11
                      Originally posted by BigDTig
                      I would for cosmetic reasons.

                      Brazing would be fantastic for most of the work I do on stainless -- it would warp less, joints would still be strong enough, etc -- but you can't grind a braze flat and it has that funky yellow color...

                      So, it gets Tigged. I don't do a lot of Alum, but would weld it instead for just the same reason.

                      explain how Brazing would cause *less* warpage ?

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                      • #12
                        Brazing of Aluminum.

                        Jeff I would not want you to be unhappy because you just spent money on a Dynasty 300 DX. I could always use a second one. If you want to sell it and buy a propane torch from Harbor Freight just let me know.

                        JCBINC.

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                        • #13
                          Originally posted by arcdawg
                          explain how Brazing would cause *less* warpage ?

                          Less heat = less expansion

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                          • #14
                            Originally posted by Luna
                            Less heat = less expansion
                            Exactly. Stainless is increasingly warp prone as you approach welding temprature.

                            At least, that's my experience with it.
                            BigDTig, Dallas, Texas
                            Miller Dynasty 200DX
                            Coolmate III Cooler
                            Miller Spectrum 125C
                            Ellis 1600 Band Saw
                            Ellis 9400 Drill Press

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                            • #15
                              I disagree on brazing causing less warpage of stainless. The total heat input is larger and over a larger area. The TIG arc although 4 times as hot is in a much smaller area and the total heat input should be less. You also get the option of a pulser with TIG
                              Dynasty 200 DX
                              Millermatic 175
                              Spectrum 375
                              All kinds of Smith OA gear

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