my first welds that one can recognise as welds + brown stuff

[Gas mark 5]

Hi all!
I have been attempting some welds inside and now they are... well they are just about recognisable as welds. However, I am getting a lot of brown patches on them that after it has cooled down, ping off and leave it all shiny. Is this due to lack of gas, dirty metal, wrong technique or what?
Thanks in advance!

 

[Hitch]

Looking a lot better now.
The brown stuff is silica (or is it silicon...) . Perfectly normal for a few bits of that to rise to the surface.

I think its formed from the silicon thats added to the wire thats deoxidises it.

 

[shenion]

Those welds look ok. The copper cladding on the wire will normally pool on the edges of the weld pool. Seems to be more prevalent with high CO2 or O2 gas mixes. Probably due to the weld pool cooling slower and has time for the copper float to the top.

O2/CO2 will actually burn the surface of the metal (add heat.) That will leave a brown rust residue. I think hitch is right about the silica, I seem to remember when switching to the ER70-6 wire having more residue that the -3 wire.

Increasing the gas does seem to help carry the dust away.

 

[malcolm]

Which gas are you using? Those guys look like the sort of pointy welds you might get with pure argon. Could just be too much wire speed for the voltage (or too little voltage for the wire speed).

 

[Hitch]

Thats not copper on the top of the welds, i used to think that.

 

[snowcat]

Thats not copper on the top of the welds, i used to think that.

nope silicon, as you say.......A couple of microns of copper isnt gona leave that....

 

[shenion]

nope silicon, as you say.......A couple of microns of copper isnt gona leave that....

Sure does a great impersonation of copper. About same hardness, tarnishes like copper, polishes back to same sheen.

 

[Gas mark 5]

Thanks guys (and gals)
I was using plain CO2 for those ones, I have got a small bottle of argon/CO2 but I thought that it would be best to save that until I was more experienced.
The power was set to 2 out of 4, about 80 amps...?
and a wire speed of between 3 m/s and 2.4m/s.
The metal was 1.5mm

ooh, and the wire was 0.8mm