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Anyone got experience of vertical fillet welds in aluminium??

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  • Anyone got experience of vertical fillet welds in aluminium??

    I have got to weld some aluminium as a vertical fillet, putting some 6mm thick pressed channels to the walls of a silo to strengthen it for fitting loadcells. Have tried tig in the workshop with some reasonable results going vertically up, not the best looking weld but adequate. Unfortunately, I have 48 metres of it to do onsite in the wet and cold. Also found that our tig welder keeps getting too hot and cuts out, not quite upto the job, tig is slow enough as it is without having to stop and wait for the machine to cool down. We have got a pulse mig which I have been told is ideal for aluminium, but I just can't get a consistent weld and end up with alot of smut/black oxide on the weld.

    Have tried different setting and found that twin pulse is better, but still struggling to get the weld that I want. Some test pieces have not even taken, but think that I have cured this by using a longer arc and spray transfer, makes the weld hotter but gets past the outer oxide layer.

    Does anyone have experience of vertical fillet welding in aluminium and give some pointers regarding the settings and general process? Weld does not have to look perfect, but does want to be strong.

    Thanks.

  • #2
    Sean, Are you brushing with a " Dedicated " Stainless steel wire brush & using acetone to clean the oxide off the aluminum before starting to weld ?

    ....... Norm
    www.normsmobilewelding.blogspot.com

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    • #3
      Problem solved, but feel like an idiot!!!!

      Thanks for the reply Norm, yes I do have a stainless wire brush which is used only for aluminium work. This is not the problem though, but I have found where I was going wrong.

      After posting the thread asking for help I went back to look at the welder again. I checked everything, but could not work out what was wrong, but being so close to the result that I wanted. I looked at the programs again, then realised that the sheild gas was set as pure argon, but someone had told me to use argon co2. Which is correct, if your pulse welding stainless, but not for aluminium!

      I feel like a complete idiot, have just spend the best part of two days playing about with the welder trying to get the setting right, but just pulling out my hair. Just changed the shield gas to pure argon, changed the arc length and amps, now get a perfectly acceptable weld. Almost no smut, plently of penetration and a reasonable looking weld.

      Brushing or cleaning fresh material makes very little difference, have found that the cleaning action of the arc and the shield gas is enough to get a nice weld. Only have to brush if the material is old and very dirty, even then I find that the dirt will burn off with a pulse mig.

      So happy now that I know what was wrong and I don't have to tig 48 metres of vertical fillet weld. Problem is now solved and I am getting the result that I need with little effort.

      Thanks.

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      • #4
        Silo,

        Glad you got the gas issue worked out.

        Your first post indicated a lack of understanding of the pulse process as it relates to welding aluminum.

        Use of pulse is only going to be of use when spraying aluminum. Short arc, by it's very nature, is not used with pulsing. Furthermore, wire welding aluminum is generally considered a "spray process".

        Dial those settings in correctly and you'll find that pulsed spray gives you a great bead.
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