TIG welds dull and grey in colour?

  1. Moose McAlpine

    Moose McAlpine New Member

    Messages:
    100
    Location:
    Watford
    Hi guys. I'm a bit out of practice in my TIG welding, i first started 7 or 8 years ago, and was "capable" despite being self-taught by reading and watching videos. Eventually, after dipping every tungsten i got my hands on, i could somewhat reliably take good metal, stick it together and turn it into useless scrap. My welds ended up kinda decent, but obviously not anything special.

    Then life got in the way and fast forward a few years till recently, my R Tech machine popped its transformer and i made a terrible financial decision and bought an ex-demo EWM Tetrix 230, CK TL26 torch, Gas Saver kit and more earth clamps than you can shake a stick at.

    Now every time i weld the bead comes out dull and grey. New clean metal, clean sharp tungsten (2% lanth), BOC PureShield Argon and all welds look like this:

    20190714_014209.jpg 20190714_014154.jpg

    I know the beads are lousy, i'm very out of practice and having pain in my hands lately which doesn't help.

    Any ideas what i'm doing wrong? Years ago when i first started the welds remained shiny, i think even the stainless recently has cone out dull. (Will get a sample piece tomorrow) Too little gas coverage maybe?

    Any help is much appreciated, thank you.

    (Sorry for the long rambling post.)
     
  2. Wonderweaver New Member

    Messages:
    17
    Location:
    Manchester
    Hi Moose what is ya torch set up and gas flow???
     
  3. Moose McAlpine

    Moose McAlpine New Member

    Messages:
    100
    Location:
    Watford
    Hi, Wonderweaver, for those welds it was a CK TL26, Gas Saver with a #6 cup, i think my regulator was set to 20L/min and the flowmeter (vertical ball/tube type) was about 10L/min.

    Thank you.
     
  4. Wonderweaver New Member

    Messages:
    17
    Location:
    Manchester
    Seems bout right but looking at those welds they look like you hav nt cleaned the mill scale off. You dont want that in your weld. Are you putting to much heat in or not dippin quick enough maybe taking the rod out of the gas zone ???
     
  5. Moose McAlpine

    Moose McAlpine New Member

    Messages:
    100
    Location:
    Watford
    The metal was thoroughly cleaned prior to welding, either with a flap wheel or one of those "fibre" discs like a big Roloc then wiped with acetone or brake cleaner. The second pic the coupons are clean cold-rolled then cleaned with a disc as well.
     
  6. Wonderweaver New Member

    Messages:
    17
    Location:
    Manchester
    I would check all your hoses. If there is even a small hole or loose connection the hose will pull in air .Ive had this happen on stainless which is noticeable immediately .
     
    slim_boy_fat likes this.
  7. Moose McAlpine

    Moose McAlpine New Member

    Messages:
    100
    Location:
    Watford
    I will check that tomorrow, thank you.
     
  8. Joe Irvin

    Joe Irvin New Member

    Messages:
    13
    Location:
    West Yorkshire, United Kingdom
    Hi @Moose McAlpine

    Is there a deposit around that lap joint, almost like dust or soot? Looks to me like you’re pulling air in somewhere along the way. Do you have a white/yellow deposit on your tungsten after you’ve finished welding?

    As @Wonderweaver said, check your connections. Set everything up as you would when welding, open the bottle then apply some soapy water to all connections and along the hose. It will start blowing bubbles if there’s a leak.

    Check your settings too - it looks like you’ve got some excess pen on the lap joint test piece you’ve done. Make sure you’re not welding too hot. Give yourself some pre and post gas.

    How long have you had your gas? It is always possible you may have a bad batch of gas. Check your flow rate and make sure your reg isn’t damaged.

    Lastly, when you’re welding, make sure your filler wire stays under the argon coverage as you’re dabbing it in and out. Feeding oxidised material into the pool can make a big difference.

    Best of luck,

    Joe
     
    slim_boy_fat likes this.
  9. Liquid Metal

    Liquid Metal Member

    Messages:
    419
    Location:
    Essex, UK
    There may be a leak in the gas hoses, and also the point that with the box section offcut welded onto the plate that the material still had scale on it.
    But in my opinion the greying of it isnt gas flow rates, isnt ceramic sizes or whether you're using gas lenses or not..... its heat input.
    What sort of amperage are you using for the fillet weld (as a starting point), and what size filler rod are you using? Also, are you using a footpedal or a torch button with upslope?
     
  10. Richard.

    Richard. Member

    Messages:
    17,814
    Location:
    Cambridgeshire
    What exactly are you expecting from welding with mild steel?
    It doesn’t look shiny. Dull and grey is the norm for mild steel unless you weld it very cold. A Matt silver grey finish is about right.
    The finish on your fillet joint looks about right. Your lap joint looks like your arc length/torch position and everything is just wrong. Don’t expect results like you’d get on stainless.
     
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  11. Mark Whelan New Member

    Messages:
    1
    Location:
    Hemel Hempstead
    Hopefuldave and mtt.tr like this.
  12. carbon

    carbon Member

    Messages:
    1,061
    Location:
    S. Glos. U.K
    Lots of references to that on this site search ‘brake cleaner’
     
  13. Munkul Member

    Messages:
    342
    Cumbria, UK
    Most brake cleaners these days in the UK are non-chlorinated specifically to avoid this danger. But I'd always recommend buying proper solvent... Acetone is readily available, safe, stronger than any brake cleaner, cost effective and brilliant for cleaning all kinds of things.

    Possibly a slightly long arc going on there, putting lots of heat into it, otherwise they aren't bad welds.
     
    Mark Whelan likes this.
  14. The welds look a tad hot but you are not going to get shiny TIG welds on carbon steel unless you go in really cold
     
    Dcal and Richard. like this.
  15. Moose McAlpine

    Moose McAlpine New Member

    Messages:
    100
    Location:
    Watford
    Not really a deposit, but a little discolouration:

    20190714_232957.jpg

    The gas is quite new. It's PureShield argon from BOC, i got the cylinder only a few weeks ago. Flow rate is 8-10L/min, regulator is new, i bought it when i got the cylinder as it's a different type. (E50 Cylinder)


    I'm trying but my positioning/filler feeding needs more practice.
     
  16. Moose McAlpine

    Moose McAlpine New Member

    Messages:
    100
    Location:
    Watford
    I checked the hose and it's intact, all connections are fine.

    All the material was thoroughly cleaned before welding. There's scale inside the box section, but all welded surfaced were cleaned of all scale/etc.

    Filler rod is 1.6mm ER70S6, i'm using a foot pedal (switch kit arriving tomorrow) and going by 40A/mm, that fillet with the box section was done at about 115A.
     
  17. Moose McAlpine

    Moose McAlpine New Member

    Messages:
    100
    Location:
    Watford
    It might just be my imagination but i thought my previous welds looked "cleaner" with more shine. Maybe i was welding too cold before, it was with an R Tech 201 and the torch it came with, using normal WP26 parts (not CK Gas Saver)

    That lap joint is especially bad. You're right, everything about that one was wrong.

    Previous welds, before i became useless:

    20190403_171544.jpg 20190403_025033.jpg 20190403_171524.jpg 20190403_171531.jpg 20190403_171514.jpg
     
    Dcal likes this.
  18. divya_mathur pre-moderated

    Messages:
    2
    Location:
    Delhi, India
    Due to overheating of metal tig welding becomes grey or dull in color and that also degrades its corrosion resistance and mechanical properties also. To get rid of grey or dull color you need to increase travel speed or shorten the arc length.
     
  19. Liquid Metal

    Liquid Metal Member

    Messages:
    419
    Location:
    Essex, UK
    It was the lap joint was the one that looked like it was overheated to me, ie the wrinkled surface. Bit of a tricky one as need to balance out amps, arc length and speed the same as a fillet, but not use a 45deg angle, ie have the angle favouring the lower piece a little.
    A button start i definitley prefer myself though, as if things are getting a bit hot sometimes with a pedal, its too tempting to back off the amps and leave the other factors the same, which can let the problem snowball and get worse as you go along.

    With a button on the other hand, (unless you were WAY over the top with amps lol) youd either up the amount of wire you're adding or the frequency of adding it, up travel speed a bit, and keep arc length as short as possible.
     
  20. Dcal Member

    Messages:
    1,005
    Location:
    Antrim Northern Ireland
    Thank god you posted that, I was beginning to wonder as all my mild steel welds are dull and grey.

    See photo below of a weld on a bracket earlier tonight, nothing critical and just tig welded it for practices.
    Minimal prep and no cleaning.
    Probably a bit hot and I didn't let it cool between runs, but 2 seconds on the bench grinder wire brush and half of the weld is nice and shiny.
    Fair enough my welding is nothing to write home about but it is easy to make it shiny if that's what your after.

    IMG_8568.JPG
     
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