Welding issues

[LaCroix]

Yesterday, I suddenly had issues with my MAG welder (I use 100% CO2, 0.6mm wire ).

I normally run pretty nice welds, but today, somehow, it started to spit globs of filler wire at the target. I mean, there is suddenly no puddle, but coral-like globs of metal building up that 'stick' to the surface. Grinding them off, it looked like there was a bit of fusion going on, but I didn't trust that weld, at all.

No change of wire, I did change the nozzle (the insulation sleeve on the old one broke) - I used various nozzles to test once that issu started, but all produce the same error.

The gas seems fine, still at 12l/min (I do have a bit of draft in the shop, so I use more), and gas is exiting the nozzle.

It's not an issue with the material, neither - plain ordinary 2x2 stock, 2mm, the same as I used a million times, before. I finished using my stick welder, which welded nicely.


I never had those issues before, and din't know if there might be something broken on my welder. Any ideas?

[madd0ct0r]

not oil on the surface of the stock?

the stickwelder worked, which suggests it might be the gas or maybe the wire feed mechanisim. If something was a little off there the wire coming in fast then slow could result in the overheating you had?

I dunno - the coral formation sounds like you had something entrained in the metal that was boiling off. Slug inside the stock?

[LaCroix]

A thorough check showed that the new nozzles were 3mm longer than the old one. On a whim, I ground one down, and everything worked fine again. Maybe they updated their standard nozzles for a stronger machine...

[madd0ct0r]

this is the nozzle for the gas, or the wire extruder?

[LaCroix]

The gas nozzle (the outer, visible part of the welding gun). Looking up my welder's specs, the contact tip is supposed to be quite close to the nozzle, maximum 3-5mm recess, if I get the pictures right (sadly, no spec table was included with that welder), and about 2mm when I look at the old nozzles. With the new nozzles, it was about 8mm away from the nozzle aperture. That of course completely fucked up the to work distance, causing the gun to spit already molten wire, causing that strange buildup. It was a form of extreme splatter (which is even worse due to the pure CO2 I'm running - that stuff splatters more than CO+Argon)

I might try to grind some other nozzles a bit more than the now working one and see if it improves the weld further.

[madd0ct0r]

cool, that's a useful tidbit to know.