Some black soot around alum mig welds is normal. It is fine to switch to 4043 but you need to get it to work with 5356 also. 5356 give you a much sronger weld than 4043 and is good to use on high stressed welds like boats and trailer frames. I would send yofish a pm and get his advice but if you do a search he gives Kempy some very good tips and starting points to mig alum. 4043 has silicone in it to make it flow better and for most work it is ok to use but even for high stress tig welds 5356 is the way to go. I have no clue what the greenish flame would be other than some contaminant in the gas or a leak sucking in air. I would try going to .035 spools and see if that helps. I have always used .045 and had no problems but your welder might work better with it. I know my MTS250 does not like flux core wire at all. So far I can not get it to run .045 hobart 21B to save my sole. I can put the same wire in my millermatic 200 and it runs fine and also runs fine in my miller extreme suitcase feeder hoked up to my trailblazer. I hoped to replace the extreme feeder with the MTS but it does not look good for that possibility right now.
Last edited by TheGary; 07-22-2015 at 11:02 AM.
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