hello, my first attempts at mig

[dooscoop]

hi
i have done a bit of arc welding before but not a great amount, i am learning to mig with a borrowed sealey 135xt. I have been trying some fillet welds on 5mm steel and i am getting some small pinholes can anyone tell me why this is happpening thanks

 

[steeo]

What gas are you using ???

 

[malcolm]

The second one doesn't look too bad. The third one has no shielding gas - if you look at the end it's full of holes.

Gas problems are common especially if you use the disposable bottles. Apart from anything else they run out very quickly.

 

[Wozzaaah]

Lack of shielding gas is causing that porosity.
1st one, insufficient gas, 2nd one, very nice indeed, 3rd one insufficient gas again.
Disposable or refillable cylinder?

Edit: Malcolm beat me to it, that'll teach me for putting the kettle on mid-reply!

 

[dooscoop]

thanks for your replies, i suspected that it was a gas problem. as i said i have borrowed the welder so i didnt know how much gas was in the bottle. i am using dispoable bottles with a c02 argon mix, i have been out and bought a couple this morning and had another go.
the weld seems better, here are a couple of welds i have just done.

 

[Wozzaaah]

Spot on!
Disposables are a waste of time if you have a fair amount to do, they'll only last for about 10 minutes of welding.

 

[dooscoop]

yeah the disposables are a bit expensive but its not my welder im just having a go. i have been making a mounting bracket for a master cylinder/servo and brake pedal for my repo 1932 5 window ford. i did most of the weding with my arc welder, i just wanted to have a go with the mig cos at some point in the not so distant future i have got to make an exhaust system for it and i need the practice, havnt decided yet wether to go with mild steel or stainless for the exhaust
any ideas where i would pick up a larger gas botle when i decide to buy my own mig?

here is a couple of pics of the bracket i have made not too pretty, but functional i hope.