Spool guns & Aluminum, Got Aspirin?

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Hey Guys, I’m new here, (really like the place).You’s all seem very friendly and supportive,I’ve been Having so much trouble with mig’ing aluminum, Here’s the Low Down:Material:2x2x0.1250 SQ Tubing2x2x0.100 SQ Tubing2x11.75x0.065 Grip Strut3/16x2 Flat BarWelder’sMiller 251 / Spoolmatic 30A ESAB 203 / ST-23A Spoolgun Wire: ESAB 4043 0.035 Mig Wire, (I’m using 0.45 tips)Gas: 100% Argon.I have been welding with this setup for about 6 months now. But my welds look like ****, they hold and are flexible. But I have a job that’s requires pretty welds.Would a Argon/Helium mix work better?0.030 wire / 0.035 tips?Should I be preheating my start points?Should switch the polarity?I really would love to stay away form tig’ing (meanly because I have never done it).I’ve have been cleaning my material with a stainless steel brush.I’m fresh out of id’ers! Please help, I getting pretty dang frustrated!  Thanks, Eh!
Reply:First, I would try to get a tip as close to the wire size as possible. Second, clean everything really good, this means also using Acetone. Third, keep a seperate pair of "clean" gloves after final cleaning of the material to handle and weld. Mig of aluminum isn't the best looking to start with, so you'll have to make a few sacrifices, but it can be done and made decent looking.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:I tried the Acid, MAN DID IT HELP!!! Thank youI’m also having a hell of a time finishing a pass without a “big black crater”. Any Suggestions? Also, would I be a retard to try a 33% helium / 76% Argon mix JUST to get rid of the smoke? What would be a con?Could I control the heat better by welding at 180 amps(instead of 200) , with helium induced heat, and pulling back(boarding the atmosphere)  to finish a pass?  Thanks, Eh!
Reply:Originally Posted by MikeFormMooseI tried the Acid, MAN DID IT HELP!!! Thank you
Reply:Funny But, Don't quit your day job.  Thanks, Eh!
Reply:You can try using the mix, it certainly wouldn't hurt and help burn a little hotter.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:OK, I tried .030 4043 wire, (oversized tip-0.030 tip burntout every 3rd pass)I’m not getting the best penetration (I cut it & inked it) But it works.Still getting the the “big black Crater” I don’t care about the smoke, but the crater!!!!(see the picture)I cant figure out how to finish the pass. Any help would be greatly appreciated! Attached Images  Thanks, Eh!
Reply:To some extent, you are going to have a little bit of the black crater.  It helps to preheat your aluminum but be careful w/that on the thin material.  At the fab shop where I used to work, when we migged any Aluminum, we always filled in the craters with TIG just to make sure that they wouldn't crack and to give them a nicer look.  Just my $.02
Reply:Tie it off to the source metal quickly, then grind it. Some people also do a circle and build it up, then you can always grind it off.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Hmmm, Miller recommends 0.035 4043 wire at 350-400 ipm and 21-22 volts at 110-130 amps for 1/8 aluminum workpieces.  Spray transfer, not short circuit.  Are you in that range?Clean the work well with acetone, brush it with a clean stainless steel brush used only for aluminum, wipe down the joint area with some acetone again (remove the acetone rag from the weld area before welding!), weld away.For the crater, dwell on the end point for a heartbeat or so.Black soot/scorch mark, can you adjust the post flow gas time?  Or increase the gas flow rate up a bit to get some more argon to the weld zone?  Miller recommends 20-30 cfm of pure argon for aluminum weldingAlso, use a push/forehand not drag/backhand on the gun travel.Maybe you are jamming the torch tip in too close as well?  Stick-out of 3/4 inch?  Also, recess the electrode tip 1/8 inch into the nozzle if possible.
Reply:thank-you all for youre sound advice!!!Very Helpful!!!Moon, i set the welder 19v 290 ipm, 110 amps, works like a charm! But i like the flat weld .030 gives me.thanks agian!!!  Thanks, Eh!
Reply:sometimes with ally mig the problem of black or dark orange craters/debris is the contact tip we use a fronius machine for all our ally welding the tig is now redundant but we had alot of problems that turned out to be the tip copper deposits were burning off from the contact of ally and copper we now use ceramic/copper mixed tips there alot harder than standard tips our welds are now brighter than the new material we are welding
Reply:Moose, looks like you have it licked, all sage advice. Aluminum REALLY likes to be kept clean, any impurities will show in the weld. Moon hit all the good spots. Definitely dwell in the crater at the end of the bead. If you can set your machine to post flow the gas, it should alleviate the balck at the end.  You said you liked the flat weld .030 gave you, what are you getting now?
Reply:with 0.035 the weld does have better penetration(blows and bubbles through-if youre not movin like a ----Insert Off Color "Funny" Here ---). 0.030 only penetrates a quarter ways through 3/16(i invested in ink/die-its so cool). But .030 is more forgiving, and the weld is flater (looks more like a tig weld) I few things i did find out today:to help reduce the smoke, use a pure argon gas. (ask your gas man about it - plain argon is drity)And to reduce the crater at the end of a weld -stop-start for 0.5 sec-stop.They have guns now that when you let go of the trigger they step the amps back to finish the weld.O i should just be tiging this crap anyway - why am i so scared of tiging!  Thanks, Eh!
Reply:Pretty, precise, slow = TIGNot as pretty, not quite as precise, Lots faster = MIG/GMAWdepending on operator skill, of course.