Brown staining/sooty deposits

[Sphinx]

Quicky really:
When doing spot welds or short 'bursts' like the thin metal technique, is it the norm to get a kind of brown stain around one half of the weld?
I've got the Argoshield set at around 11-12 L/min and when I get a seam going it's nice a clean, but with short shorter bursts it's not.

Also (bit of a rant) Why can you do a great weld one day and then the next day it's utterly shameful?! I've just been practicing on a bonnet and found the edges where the skin is folded over were really thin and if I blew through the smallest amount then the seam sealer on the other side would instantaneously melt into some nasty oil like substance and make the weld explode, all in a fraction of a second.
After all that, I got some of the steel I was using the other day and did a couple of vertical and horizontal seams on that just to prove to myself that I could weld after all lol

 

[R Kraft]

It sounds like the shielding gas is not covering the weld before the arc starts.
Trying to weld things you can't clean, is demoralizing, but that's how auto welding sometimes goes.
Robert

 

[bigbadbugga]

The brown stain around half of the weld is because there is no sheilding gas on that side, try changing your torch angle closer to 90 degrees to the job.