Machine gun symptoms (stainless)

  1. andy198712 Member

    Messages:
    31
    Location:
    Cornwall
    Hi,

    I have a 135te welder and I’m welding 316 stainless pipe which I believe is 1.6mm

    I brought stainless wire and still using normal welding gas mix.

    I seem to find when I start the weld it sort of machine guns then after a second goes to a nicer clean bead....

    still pretty rough, it seems a lot hard to weld then mild steel!? I was okay at that.
    This is just making me look bad :)
    it’s only for a personal exhaust. But didn’t want to use mild wire.

    Is that symptom caused by wire feed too slow or ? Just strange it flows well after a second or two....?

    cheers
    Andy
     
  2. Country Joe Argoshield Dark

    Messages:
    1,187
    Location:
    Somerset - United Kingdom
    Hi there,

    I think for a start, the gas is wrong, but that won't be the cause of the "machine gun" welding.
    It's more likely to be the wire not feeding correctly at the start of the weld.

    It could be that the wire is a different diameter from the last reel, and the feed-rollers haven't been changed around, but if you're using the same size of wire, that's fairly unlikely.

    Are the pinch rollers gripping the wire properly?

    If you were to try to pull the wire out from the end of the torch by hand, does it come out quite freely.
    If it comes out too freely, you may need to tighten the feed rollers slightly - sometimes even for the "same" diameter wire.

    Also, some really crap wire (usually un-branded?) sometimes doesn't always maintain the same diameter throughout the reel, but I'd expect most stainless wire to be reasonably uniform all the way through the reel.

    If you ever travel anywhere with the welder, maybe the reel gets tightened up to stop the wire from un-spooling while driving around, and hasn't been loosened off since - giving the wire drive motor a heavier load to push up the (clean?) liner.

    Also, if there is any grease wihin the drive gear, it can harden up in the same way it does in an angle-grinder "gearbox".

    You could also try adjusting the wire speed, as you mentioned above.

    Sometimes it's easier to get an idea of the feed-rate by turning it up so far that you can feel the wire stabbing into the work-piece, and then backing it off a wee bit.

    I suspect you may know all of this already, in which case I apologise for patronising you!

    Anyway, I'm out of ideas for now, but I'm sure others will have more to add!

    All the Best,
    CJ
     
    F.J. and arther dailey like this.
  3. Richard.

    Richard. Member

    Messages:
    18,141
    Location:
    Cambridgeshire
    There is no point using stainless wire on an exhaust unless your going to use it properly to reap the benefits of a stainless joint.
    Ie use the correct gas and purge inside.
    If you are not going to do this then the joint you put down will probably have even less benefits than a mild steel joint because coked stainless welds under heating and cooling cycles are prone to fail.
     
    mike os likes this.
  4. mike 109444

    mike 109444 Member

    Messages:
    4,090
    uk Bristol
    Are you still using the original plastic liner ?
     
  5. andy198712 Member

    Messages:
    31
    Location:
    Cornwall

    CJ
    Thanks for the reply, always happy for help :)
    yeah may well be slipping on the rollers at the start, i'll look into that, although i tried a pinch test and it pushed out the wire okay. i may have a play with it some more.... or i may sack off the stainless wire and go back to normal wire!

    both 0.6mm wire, both "super 6" commonly found brand.

    i'll have a play and see :)
     
  6. andy198712 Member

    Messages:
    31
    Location:
    Cornwall
    Ah i see! i didn't know that that it would be worse then mild to be honest. probably not worth the hassle?
     
  7. andy198712 Member

    Messages:
    31
    Location:
    Cornwall
    yes that's correct, just the one that came with the welder from new, its had one small spool of wire (the original one) through it and a little of a new reel so not a lot of use and i keep it clean and dry ect don't wrap the torch tight.

    Thanks :)
     
  8. andy198712 Member

    Messages:
    31
    Location:
    Cornwall
    This was tacks in the form of l l l l l l l
    As a bit of belt and braces and I had a small gap to fill
     
    • B6A33E30-5C7E-4876-874B-4A4E4CA79259.jpeg
  9. mike 109444

    mike 109444 Member

    Messages:
    4,090
    uk Bristol
    As stainless would be "stiffer" than mild that may show up issues with the feed mechanism / wire reel clutch OR the drag in the liner. It might be worth trying the cheep and cheerful net curtain wire liner as it is so cheep (< £1 meter). It should show straight away if its the cause.
    If that does not sort it then to eliminate the drag from spool or spool clutch, you could pull some excess wire of the spool and cut it. So not you have say 1 meter of wire yet to feed into the feed rollers (just hanging out the machine side) Make sure it can't touch the machine chassis as it feeds in and try welding. What this does is it rules out the spool being poorly wound or the clutch on spool spindle dragging. Take care when you cut the wire at the spool cos it will want to unravel like a scolded slinky !
     
  10. andy198712 Member

    Messages:
    31
    Location:
    Cornwall
    yeah i noticed that when it slipped out my hand as i threaded it on first time lol sendup up pulling a good few meters off the roll and binning it till i got back to good wound wire again. but the drag may to too high, thats a good idea
     
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