In theory alum mig should get more cleaning then your average 70/30 tig.Bill Beauregard wrote:Please excuse my ignorance. Does this mean cleaning could be less thorough with spool gun MIG. I haven't had much call to weld something big like this truck body. It has had LOTS of years to get dirty. I think my only chance would be to grind out a big kerf exposing clean metal but wiping in crud in the process. I had it in mind little cathodic etching happened with MIG. I think the last of the contamination would be like Dr Seuss's pink bathtub ring.AKweldshop wrote:Everyone thinks AC Equals cleaning.
It's the DCEP side that gets it for you. Speaking tig here.
You know that there is cleaning vs penetration. If you ran full DCEP with tig you would get lots of cleaning but you'd burn your tungsten back.
DCEP is where the cleaning comes from.
So DCEP with mig gets your cleaning, and it burns your wire back, producing spray. If you try mig with DCEN, your wire wont burn back very good.
That's my understanding in layman's terms.
But you have to have the right amount of heat put into the part to get the cleaning action. ( you know this if you've ever tried to add your tig filler to soon before your puddle is fully formed)
Being that you have no heat control with mig, and all your metal pouring in right from the start, it makes it hard to get good cleaning and fusion at the start of a weld.
That's why "hot-start" on these new fancy lincoln/miller pulse machines is so desirable.
In my opinion pulse helps you slow down, get good fusion and give you extra time for cleaning.