Torch angle differences for mig

by Rob
(Warren, MA)

I noticed that in the "Mig welding uphill technique" video it looks like you were keeping the gun at 90* to the workpeice. I didn't see any mention of torch angle with any of the other techniques and settings listed. How much of a difference would torch angle Make doing either uphill or downhill with the different setting and techniques?
And as a side note, i was taught that on thin gauge sheet metal, downhill is fine, but for anything structural uphill is the only way to make it sound.

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for uphill mig, a 90 degree angle works good.
so does a slight push angle of up to about 10 degrees.

for downhill mig, a 90 degree works but a pull torch angle of up to 20 deg seems to work better at keeping the puddle pushed back from the arc.

downhill mig can be effective for up to 1/4" thick if done right, but there are no guarantees.

it is very easy to cold lap with short circuit mig downhill so every effort needs to be made to avoid that.

setting machine with adequate but not too much heat,

staying on the leading edge of the puddle,

both play an important role in downhill mig.

for general fabrication on 1/4" thick and under, downhill is usually the norm.

For code welding, like on buildings, or bridges,
downhill mig or any process is usually prohibited.