Mig welding

[Ant]

Well here goes, I have been welding for years, but dont profess to be a qualified welder, did both MIG and a heap of TIG welding the TIG was mainly stainless steel, and I built stainless steel buggies with a wind sail, that my friend who started the craze off and has International factories, I find stainless steel welding with the TIG quite easy to get good penetration!
Something I didnt bother with until now is I am doing more small circles with the electrode while welding steel to achieve that nice row of dime affect!

My question is with the MIG, I am aware of a good looking weld and little penetration and the inevitable failure, and as I am out of practise, what I do is with 3.2mm steel plate, I just wind up the 190amp MIG flat out, and let rip and it sizzles away, I guess it pays to weave slightly and not go to fast to avoid what Aussie Mike mentions about cold overlap, and I suppose a drag weld is hotter and has more penetration, than a push weld! I have welded heaps of car items with a Mini-Mig about 115amp, and what we did was preheat important parts with the gas and they held up I have never had a failure.......touch wood!

Any tips gratefully appreciated as I am welding up a steel bulkhead (3.2mm) in a few days as I had to re-position my steering column, and the hole is too big, this is a low priority area, so I am welding on a vertical face and going slighty upwards anti clockwise, and would probably do 160amps and do some practise, I suppose another technique do you guys weave to really make sure the surrounding area is contacted. I looked up the MILLER WEBSITE, they list amperage and IPM wire speed.