Help with fouling tips

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I'm a newbie and I'm attempting to weld 3/16 aluminum plates into an L bracket. I'm using a brand new Lincoln Mig 180HD with a Lincoln 100sg spool gun, 100% argon with a flowrate of 12. The setting on the welder is 5/E which is what is recommended by the Lincoln manual. I'm using 4043 wire with a 035 tip.The problem I have is that when I first start to weld I get popping, a green colored light and the wire keeps melting to the tip almost immediately. The area around the expected weld is black with soot. I've tried reducing the wire speed to 3/E, and increased it to 7/E, but no luck. Any ideas what this newbie is doing wrong
Reply:are you getting gas coverage at the start of the weld >?Miller Xmt 350Lincoln Ln-25Ahp 200xSmith Gas Mixer AR/HTig is my Kung FuThrowing down dimes and weaving aboutInstagram http://instagram.com/[email protected]
Reply:also are you cleaning the base metal with a stainless tooth brushMiller Xmt 350Lincoln Ln-25Ahp 200xSmith Gas Mixer AR/HTig is my Kung FuThrowing down dimes and weaving aboutInstagram http://instagram.com/[email protected]
Reply:How do I check whether I'm getting gas coverage? I hear a hissing sound and notice air pressure coming from the nozel, also the regulator guage click and drops to 11 briefly. Yes, I used a stainless steel brush to clean the surface.
Reply:Neither gas coverage or material cleanliness is going to have an effect on instant burnbacks like that.  Generally its because wirefeed speed is too low, or voltage is too high.  If you have already increased feed speed, try decreasing voltage.I would also check and make sure you material is grounded correctly, as well as a volt sense leads that you might have.What diameter wire are you using?  Aluminum generally likes to have a slightly larger diameter tip to prevent binding and burnbacks, but this generally only happens after welding has started and heat begins to build up.  If your using a.035 wire, try reaming out a contact tip with a tip cleaner and see if that helps.Have we all gone mad?
Reply:I haven't tried the voltage, only the wirespeed. I'm using the highest output E as recommended by Lincoln. I will try to reduce the voltage down to D and see what happens. The diameter is .035 superglaze 4043 wire.
Reply:Now that I think about it, you might be better off with .030 wire.  You dont have a very big machine and aluminum takes more energy than steel does.Have we all gone mad?
Reply:You think I should keep my setting on 5/E, just reduce the wire size?
Reply:Try adjusting the voltage as well as the wirespeed and see if you can find a combination that works.  I have no experience with that machine so I cannot recommend anything.  I would think that you *should* be able to get it to work well, but if not then try going to a smaller diameter wire.What does the chart on the machine recommend?Have we all gone mad?
Reply:The chart recommends 5 wire speed and E voltage. thanks.
Reply:I meant wire size, what aluminum wire size does it recommend.Have we all gone mad?
Reply:Check all connections on your machine.  lead lugs, power lug, grounding and grounding screw. Tighten lead lugs with a wrench, not to strip them just tighter than hand tight.  Hold the gun about 1 inch from the work prior to starting arc.  Hot so far to loose gas coverage, yet not too close that burn back contact the tip.  You can move closer as the arc starts. Prior to starting the arc, curl the tip up so the burnt end does contact the work first.Make sure everything is feeding properly, no metal shaving in the gun and wire is in groove of pulley.Make finer adjustments of wire speed.Are you getting proper voltage to the machine.  Correct gauge wires and extension cord, breaker functioning properly.
Reply:Originally Posted by tapwelderPrior to starting the arc, curl the tip up so the burnt end does contact the work first.
Reply:just clip the wire at an angle on each start. also as stated already you want to hold at least 3/4" from the base metal.....jim225NT bobcatAEAD200LEScott 125mm175, mm252 w 30A, PT225mm211, TA 181iHyper Therm 380, cut master 529100X & XX, Digital Elite6 Victor setssmith little torch, meco midget kalamazoo band sawsteel max saw evoulution circular saw
Reply:Curl the tip of the wire up --  put a hook in it ( about .5-1") .  The tip will be pointing at you.   The side of the wire will hit the work. Might be the same as clipping,  however I can curl it by hand.   I think I get a softer start curling it, too.  I did a thread or three on this gun a while back.  Check those post, too.  Good luck
Reply:I haven't tried the curl/clip yet, I will later tonight when I get back home. This is what I got with my original settings yesterday, you can see what I'm talking about.
Reply:I think you are on the wrong polarity for aluminum. Check your electrode connections according to your manual.  good luck, Ralph
Reply:I just tried the curl/clip, but it didn't help. I then removed the spool gun and tried the standard nozzle with 1/4 steel, no gas, and it works like a charm. This problem seems to be specific to Aluminum. Ralph, do you mean switching the ground wire to the other terminal on the inside of the flip up side cover?
Reply:Raplh you were correct, it was the polarity. whew, I was starting to wonder what the heck was going on. I needed to have my ground on the - for MIG setting.Here is my first aluminum weld, any feedback would be appreciated?
Reply:By the way THANK YOU SO MUCH everyone!!!! This is a great forum.
Reply:Beads not bad for a beginner, make sure that you stay on the root line so that you get equal penetration on both plates.  Also be sure to keep a steady travel speed and work angle.
Reply:I also just realized that I should have used the push method, I used a pull method on the weld above. I will try it the correct way tomorrow and see how it turns out. Thanks again.