Basic amps / wire thickness question.

  1. julianf

    julianf Member

    Messages:
    5,061
    Location:
    devon, uk
    Current setup -

    Portamig 215 welder
    Parweld m15 torch
    0.6 wire

    When welding up thicker stuff (3-4mm) I've managed to set the m15 torch on fire before.

    I have to make some long welds on 6mm angle to 3mm box.


    I'll buy a M25 torch. I assume I should just go for 1.0 wire, right?

    I get by with 0.6 for most stuff (wasn't chosen, just happened to get a 15kg roll of it with the welder) and I'm thinking 0.6 to 0.8 won't really be a huge difference and I should just go for 1.0?

    Thank you

    6mm to 3mm -

    IMG_20201021_130830279.jpg

    3mm -

    IMG_20201021_130747361.jpg
     
  2. a111r Member

    Messages:
    888
    Location:
    London
    Try 0.8, that should do everything.
    Doesn't seem much but 0.8 compared to 0.6 has nearly double the csa (16: 9)
     
  3. julianf

    julianf Member

    Messages:
    5,061
    Location:
    devon, uk
    "Try"ing will cost me about £50 or something in wire, tips, postage (i have nothing but 0.6 here)

    If its 0.8 that i need, then ill go for that... i just cant quickly load up some and give it a go, if you see what i mean?
     
  4. julianf

    julianf Member

    Messages:
    5,061
    Location:
    devon, uk
    I thought there would be loads of these tables about, but, surprisingly, they seem few and far between (in metric at least, and my brain cant do the conversions on the fly!) -

    [​IMG]
     
  5. Dcal

    Dcal Forum Supporter

    Messages:
    2,351
    Location:
    Antrim Northern Ireland
    0.8mm will be my choice for 3 or 4mm.
     
    northwest and gordon stephenson like this.
  6. julianf

    julianf Member

    Messages:
    5,061
    Location:
    devon, uk
    3mm going to 6.35mm?

    I dont know if you choose by the thick side or the thin side...


    Ive never had to think about this before - i just grab the welder and spin the dials until it works! But clearly what i have wont work now with what i want to do, hence having to work by something other than trial and error!
     
  7. Munkul

    Munkul Jack of some trades, Master of none

    Messages:
    3,144
    Location:
    Cumbria
    Go by amps for wire size, and match the amps to the size of steel you're welding.

    A 3mm to 6mm weld should have a leg length nearer the 3mm than the 6mm, and the amps will be ideally set around the 4-5mm range to get extra heat into the 6mm.

    0.8 will do everything you want, its usable range goes up to 150 amps, higher if you push it but not reccomended.
     
    hunter27, metalmelt, Dcal and 2 others like this.
  8. 500e

    500e Always buy fire insurance a flood is hard to start

    Messages:
    4,969
    Location:
    SWest UK
  9. julianf

    julianf Member

    Messages:
    5,061
    Location:
    devon, uk
  10. 0.6 wire is nowhere near large enough, 0.8 or 1.00mm is what you need
     
    Dcal likes this.
  11. Mark 2

    Mark 2 Forum Supporter

    Messages:
    488
    Location:
    London UK
    I think it is about deposition rate. Surprisingly, 0.8 will put down nearly twice as much as 0.6 if my maths is correct.
     
  12. julianf

    julianf Member

    Messages:
    5,061
    Location:
    devon, uk
    To be clear -

    I have to buy one or the other (0.8 or 1.0)

    I don't want to buy both.

    I have 0.6 currently.

    I felt that 1.0 would do for the job in hand and give me more flexibility in the future.

    But there's no point in getting 1.0 if 0.8 is what I need currently.
     
  13. Mark 2

    Mark 2 Forum Supporter

    Messages:
    488
    Location:
    London UK
    .0.8 from me.
    (strictly come welding)
     
    northwest likes this.
  14. metalmelt Member

    Messages:
    593
    Location:
    UK
    I would switch to an MB25 and use 1mm wire, the 25 will handle around 250 amps without issues and they are more suited to industrial welding so more in abundance in quality brands, 0.8 realistically welds to around 160-170 amps and you have a 215 amp machine so both the torch and wire will cope with that and give you the flexibility you require along with additional safety.
     
  15. Munkul

    Munkul Jack of some trades, Master of none

    Messages:
    3,144
    Location:
    Cumbria
    If you feel the need to weld any bodywork panels at all, then 0.8 is a better choice. 1mm just doesn't run well at all under 80 amps.
     
  16. julianf

    julianf Member

    Messages:
    5,061
    Location:
    devon, uk
    I wasn't planning on throwing out the 0.6. I'll still have that and the mb15 torch whatever else I buy...
     
    Munkul and metalmelt like this.
  17. Mr Roo

    Mr Roo Member

    Messages:
    430
    Location:
    Edinburgh
    0.8mm wire will be more than sufficient for the job. I use a mig with 0.8mm wire for near enough everything in my own workshop.
     
    Dcal likes this.
  18. creepy

    creepy New Member

    Messages:
    12
    Location:
    SE, UK
    Might be worth checking what your feed rollers can support 0.6 and 0.8 is a common pairing, then 1.0 and 1.2 but I would be going with 0.8, if heavier "stuff" was to be the norm then poss move to 1.0 but 0.8 is a nice std for most light work.
     
    northwest, a111r and Munkul like this.
  19. Turbo Member

    Messages:
    3,846
    Location:
    Fermanagh, Northern Ireland
    I use 0.8 for everything, from body panels to thick plate up to 10mm.

    Think of it this way - you can stick weld any thickness of metal with a 2.5mm rod, but you will need more passes & joint prep on thick plate. 3.2 or 4mm rods will make things easier but you will need a welder that can run them nicely.

    Another thing to consider - is your welder able to run 1mm wire properly? To get your full 215a you will need a 32a supply and the full 230v supply. If your workshop is a long way from the incoming mains supply you will suffer significant voltage drop that will affect the welder output. Put it this way - you would get better welds running the 0.8 at its upper limit than trying 1mm at its lower limit.

    I would go for the MB25 & a 0.8 setup if I was you.
     
    Nauticus and Mark 2 like this.
  20. metalmelt Member

    Messages:
    593
    Location:
    UK
    Munkul, he already has the 15 and 0.6 wire, Julian wanted flexibility and with a 215 amp machine and the 25 along with 1mm wire he would get this as this allows him to switch to the 15 with 0.6 and go to the 25 with 1mm wire so he wouldn't be running it at under 80 amps and he could safely use the full capacity of his machine safely.
     
    julianf likes this.
Advertisements