Real issues today

[alexanderfoti]

Hi all

Im not new to welding, but new to MIG welding, only used an Arc welder in the past.

I have had some experience with this MIG welder (a wolf weld unit), but today I was working on my exhaust and just couldnt get a good weld.

I did a lot of playing around with speed settings and power settings, but just ended up with this:

This was using 0.8mm wire and CO2 gas. There was a lot of spatter with the weld and it was spitting back alot, It was hard to get a consistent bead. There was also bad penetration. Its a 140 amp welder, and it was set to 5 of 6 power settings and 60-70% wire speed.

I also used a bit of flux core when I ran out with the same results:

The metals where ground down to shiny silver before starting so where pretty well prepared.

Any thoughts where I am going wrong and why my welds where so crap Any help would be much appreciated.

 

[super noob]

Polarity set right ?

 

[alexanderfoti]

AHHHHH I knew I forgot one thing!

Ok so the gas shielded weld, the first one, would have been with the wrong polarity. The second one would have been with the correct polarity, so that explains why the first one was so bad, but the second one wasnt.

 

[shenion]

Did you have the polarity correct?

Looks like you need more power. If you used an extension, it heeds to be a heavy duty one.

Oh, you mean MIG not TIG.

 

[alexanderfoti]

I do mean MIG, its been a long day heh

Ah that may be it as well, I was using a shed power supply, but thats off a 30 amp mains wire, no extension lead per se.

 

[Justme]

Do you mean MIG & not TIG?

Looks like the voltage settings were not high enough & to much wire feed or to slow travel.

How thick is the steel?

Did you leave a root gap?

Could also do with a better clean up & looks like the gas flow was a bit low.

I would grind it all off & start again.

Get some off cuts & practice first.

 

[alexanderfoti]

Yup MIG not TIG

I was maybe having supply issues becuase the voltage was set pretty high for the machine.

It was 3mm steel and there was a 2mm gap between the pipes when starting off.

I was pretty good with the cleanup, angle grinder disk on all metal before I started, brake cleaner on the metal and wire brush every time I stopped.

Yeah, Im going to grind it off completely and re-do it.

Thing is, I have used the machine before in the past and had good results,

 

[Badger1bear]

you should not use brake cleaner !!!!! when you weld it will give off a gas that will be harmfull to you !!

Phosgene !!!

 

[alexanderfoti]

I say brake cleaner, but I mean de-greaser.

Dont worry, its not the stuff that makes phosgene!

 

[the repair man]

More power, more gas, slower wire feed..what is the metal? the weld looks like it's sitting atop the metal, did you try just doing a few spots, to see if you could get the full penetration? this would give you a better idea.

 

[alexanderfoti]

I will look into the power source then.

black steel, there was little penetration, it is mostly sitting on top. Agree on more power thing, will check out the source of the power to the welder.

 

[Badger1bear]

is that stainless to mild steel ?

 

[alexanderfoti]

no both mild steel

 

[Badger1bear]

no both mild steel

your first picture looks like mild steel on the left and heated up stainless on the right ??

 

[alexanderfoti]

Defo both mild steel, the one that looks like stainless is the new dark steel, the other is from the car so a bit rusted.

 

[the repair man]

your first picture looks like mild steel on the left and heated up stainless on the right ??

Looked like stainless to me, that's why I asked, and he would have had similar results, back to the drawing board then!

 

[Badger1bear]

Defo both mild steel, the one that looks like stainless is the new dark steel, the other is from the car so a bit rusted.

the new dark steel one is most certainly mild steel but to me the one on the right looks like a stainless exhaust that has gone hot over time and gone light brown

 

[alexanderfoti]

Its possible that its stainless I suppose, but I have never seen a stock Mercedes exhaust pipe made from stainless steel and I have seen a fair few in my time.

 

[Badger1bear]

but we digress, get some scrap exhaust and practice on that first, turn ya power up on some scrap and see how much is needed before you blow thru, those are some ugly boogers on there lol

 

[alexanderfoti]

those are some ugly boogers on there lol

Tell me about it heh, will grab some of the pipe I cut of and give it a go.