A Macro Etch test also known as a cut and etch test is a very valuable teaching tool. Its a destructive test but it can verify settings and technique and since you see the results in a matter of minutes, the puddle is still fresh in your mind. Did it penetrate like you thought? One Cut and Etch ...

This is a quick video showing mig welding thick to thin material.

5F position means the axis of the round member runs horizontal.
This video shows technique and hand position to maintain a good mig gun angle

In this video...Mig Welding settings, techniques and tips for a 5g 6 inch sched 80 pipe with downhill root, uphill fill and cap

Repairing a rusted out hydraulic tank on a mobile crane. Process used: MIG and Plasma Cutter | Material: Carbon Steel

A look at a quick welding job on a tractor rim. This entire job took about 3 hours. Process used: MIG STICK | Materials used: Carbon Steel, 7018

Lots of Discussion happens when you talk about mig welding downhill. Personally, I prefer to go uphill on anything 3/16" and thicker. But for open butt root passes in pipe welding in fab shops, downhill mig is pretty common and yields good results provided the bevel, gap, fitup, and land are with...