Welding Tips and Tricks

Hey guys

I thought I would ask some advice on the first few aluminium welds ive done. I have a Cigweld Transmig 200i (Australian, Thermadyne machine).

I have a 4" spool of 5356 1.2mm (3/64") and ended up using knurled drive rolls as the U groove rolls were slipping too much.

I have some scrap (6061 i think) 3mm (~1/8") plate which I have been mucking around on. My question is in regards to spray, globular and short circuit transfer.

It seems spray is way too hot for this material and leads to too much penetration and big end craters. I can get a nice looking weld (maybe a little convex) at around 270 IPM 17.5V (1st photo) and a bit hotter 315 IPM (2nd photo).

Without trying to join some pieces I'm not too sure what I should be aiming for. Also, lots of smut outside of weld zone (weld is clean) and changing gas rate doesnt seem to make a difference.

Thanks

The soot outside the weld is part and parcel of MIG welding aluminum. A good brushing with Stainless Steel and an Acetone wipe afterwards will clean it up rather nicely.

Ok thanks.

I have purchased a cheap PTFE liner to swap out the steel liner as it was struggling with the thicker wire (although I havent had birdnest issues, just rollers slipping). I dont think knurled rollers are a good idea longer term as it seems to shed aluminium filings which would eventually block up the wire liner.

Erratic wire feed could have been causing erratic arc and some of the problems I had getting consistent welds.

You nailed it. That's exactly why you don't use knurled. Try a slightly bigger tip as well as the ptfe liner, because the wire expands a lot when the tip gets hot. You can buy 1.4mm tips for 1.2 wire. If on 0.9, just go for 1.2.

Ps, Welcome to the show, from another aussie.