weld blowholes

[justin pane]

I'm an absolute beginner to mig welding and would appreciate some tips on what am I doing wrong (see pic) I'm using a argon/co2 mix, .6mm wire and the steel is 3mm.
I cannot understand why the weld starts ok and then blowholes develope.
what am I doing wrong?

 

[madkayaker]

what flow rate of gas are you using looks to me like oxygen getting into the weld pool

 

[justin pane]

blowholes

About 4l/min about 8bar

 

[Wozzaaah]

That's too low Justin, it needs to be somewhere up near 10 lpm.

 

[runnach]

As said, up flow rate a tad, as you can see, about 2/3 of weld is fine, your arc length and tilt angles are wandering as you progress along the joint.

 

[justin pane]

That's too low Justin, it needs to be somewhere up near 10 lpm.

just increased gas pressure, a vast improvement, didn't realize it was that critical, (I've got a lot to learn)
thanks for advice,

 

[runnach]

Not enough gas = insufficient pressure, air penetrates gas shielding area.

Too high a gas pressure = turbulance, which in turn can draw air into gas shielding area, resulting with porosity.

 

[Wozzaaah]

just increased gas pressure, a vast improvement, didn't realize it was that critical, (I've got a lot to learn)
thanks for advice,

You've been on here long enough, you should have done more reading!

 

[justin pane]

You've been on here long enough, you should have done more reading!

Point taken, (if only life was that simple)
as I,m now retired I'll have more time to read and learn.
but thanks again for the advice.

 

[Wozzaaah]

Hehe, just kidding of course Justin, welcome back.

 

[madkayaker]

i got something right for a change! Gas makes a big difference one of the first things i did was throw away the disposables and get a proper bottle

 

[tux]

i got something right for a change! Gas makes a big difference one of the first things i did was throw away the disposables and get a proper bottle

It was THE very first thing I did!