Amperage vs thickness.

  1. Tom_ERST_S2 Member

    Messages:
    27
    Location:
    England, Cambs
    Here's a question, over here in the UK people always talk about using 30 amps per mm for mild steel. Yet in the USA the rule of thumb tends to be 1 amp per thou. As 40 thou is about a mm that makes it 40 amps per mm for mild steel as a base line. So why the difference in amperage? Is it due to technique or is it for some other reason? Just curious as I find 30 amps per mm works quite nicely.

    cheeRS

    Tom
     
  2. Richard.

    Richard. Member

    Messages:
    18,005
    Location:
    Cambridgeshire
    They could be referring to the fillet joint Tom. 40amps per 1mm on a fillet is about right. 30 is more suited to butt joints. Rules of thumb are a waste of time unless the joint is specified. Outside corners it’s about 20-25 per 1mm.
     
    Last edited: Aug 16, 2019
  3. Paul.

    Paul. Moderator Staff Member

    Messages:
    6,030
    Location:
    Northampton. UK
    I usually advise 30 amps for a butt, then add around 10 to 15% for fillets and minus the same for open / outside corners, its only a starting point and need to be fine tuned to suit conditions, material and skill, I would weld some joints at speeds and currents that most diy ers wouldn't dream of.
    As for Americans, they cant even pronounce aluminium properly
     
    F.J., Richard. and mtt.tr like this.
  4. Tom_ERST_S2 Member

    Messages:
    27
    Location:
    England, Cambs
    Yeah like I said I find for butt joints 30 per mm works well, then as you say @Paul. I add or subtract around 10% depending on if it's fillet, outside corner etc. I tend to try and weld out as fast as I can without messing up joint fusion in the root.

    I just wondered really as most of what I watch is Jody Collier's content and he tends to refer to 1 amp per thou quite a lot as a good starting point. I guess if you can travel quick enough then bumping up the amps makes life slightly easier, especially if time is money.

    Oh and the aluminium thing drives me nuts!

    cheeRS

    Tom
     
    Wonderweaver likes this.
  5. Bbe555 Member

    Messages:
    127
    Location:
    Lancashire
    Ah that's were I'm going wrong as I have been searching ebay for weeks looking for Aloominum so cant practise. :laughing:
     
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