Welding Tips and Tricks

I got a new welding rig, Andeli WSE 250 acdc with cold weld (really just Tig spot).

I bought a 40cf (10 liters in Taiwan) bottle because I can't carry a 100 pound bottle up the stairs.

I was getting terrible welds, and the tungsten keeps getting coated in black crud almost within seconds of use. When welding aluminum I'm getting blue tinged soot both in and around the weld. Yes I checked everything to make sure it's not leaking.
I ended up calling the guy I bought the bottle from and he put 95 percent argon in it. So now I know it was bad gas because you can't Tig with that, it's good for maybe mig.

Or another possibility is he never bothered to evacuate the bottle or something.

I ended up venting the gas out then vacuumed it myself using a HVAC pump. Got new gas put in. Difference is pretty clear... So if you checked everything and your weld looks like crap, check the gas. Also buy from local gas suppliers, don't order the stuff. Weld isn't perfect but it's looking much better without any blue black soot, but it's still not perfect, maybe the machine needs time to purge whatever's in the machine. Or it's my technique.

Oh I forgot to add, I've tried various settings on flow rate and for a number 6 cup, 3 or 4 liters per minute seems to give the best result. Higher flow doesn't improve anything, if anything it makes it a little worse and wastes gas.