5356 weirdness

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Alright, so here goes. I had a weird issue I just can't seem to crack with 5356 filler on aluminum. It's happened to me only once before. Maybe someone has an idea.When welding, right as I introduce the filler, it adds a bit of soot. There's also usually a little of a flash of green light. The first "dab" of the bead is ALWAYS the worst. Even after the initial one, though,it still seems to add a tiny bit of crud every dab. I was getting set up for a quick little ditty and it started happening on test pieces. I tried the following:Machine set at about 130 amps, but not using full pedal most of the time. Brand new cup, collet body and fresh tungsten (3/32" E3)changed gas linescleaned filler rods with acetonecleaned part with acetonewire brushed the bajezus out of test pieceTiny stickout, medium stickout, way too long but i had to try something stickoutLow gas flow, medium gas flow, way too high gas flow, but again, i had to try somethingRegular arc length, arc length so short it's almost touching. On the surface, if someone told me these circumstances, I'd probably say it was melting the filler a bit before it got under the shielding gas.. I even tried keeping the filler super close to the arc but not in to try that out. But if I think anything, this has to be it. Nothing else makes sense. Maybe filler angle too? I tried putting the filler in almost flat with the damn piece and it still fought me. Also tried almost perpendicular torch angle as well as usual canted angle. Anyway, anyone had this experience before?
Reply:try cleaning the rod with a scotchbrite pad before wiping it with acetone. The acetone wipe is good to clean up after the brushing too.
Reply:I only have questions at this point.Aluminum and at 130 amps but not full pedal - what thickness is the material?  Must be quite thin.What size filler rod?Is there a reason you are wire brushing the heck out of it?  Is it new material of a known type?Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:I've noticed some of that before also.  Especially like you mentioned at the very beginning of the bead at the edge of the plate.  I also tend to get it some times when coming to the end of an out side corner joint.  Best I can figure is that when you're near a edge like that some weird eddy currents in the gas flow going by the edge cause a bit of air to get sucked in.   That green light is caused by some of the magnesium vaporizing off.   You won't see that with 4000 series wires.You'll also see that green light pretty constantly when running on DCEN with high helium mixes and trying to use 5000 series filler wires.  That's because the puddle is significantly hotter and it's vaporizing off more of the magnesium.  If you see the green light when using DCEN, helium and 4043 filler (what I prefer to use when welding aluminum this way) it most likely means you've got balloon grade helium instead of welding grade.That green light is also a pretty good indicator that what some one told you was an aluminum casting they wanted  fixxed is actually a magnesium casting.This is just a SWAG on my part but I think some of those black smut spots are residue left over from when some of the magnesium vaporizes off (for what ever cause).  Between dabs if you pull the hot end of the filler rod to far back from the puddle and it gets out side the gas envelope it will oxidize.  Then when you put it back in the puddle it's a source of contamination that besides lowering the strength of the weld (due to oxides being diluted in to the weld metal) could also possibly be causing some of those smut particles.  Just think'n out loud here.Are you using a regular collet body or a gas lens?   You'll have less problems with that if you use a gas lens because it gives a smoother more laminar gas flow that's not as prone to those eddying effects that can cause tiny sips of air to get sucked in.  I know those tiny black smut spots are bothering you because they represent a less than perfect weld but I think you'll just have to come to accept that you're going to have some of it at times.  Especially with 5356 filler.
Reply:Yep green is from the magnesium. You will notice it with 5356 wire or even a little with 4043 wire welding on 5000 series aluminum.Torchmate 2x2 CNC with Flashcut CNC controlsHypertherm Powermax45 Esab ET220i Razorweld 195 MigRazorweld 200ac/dc TigTormach 770, Tormach xstechRazorweld, Vipercut/Vipermig, SSC Foot Pedal Dealer
Reply:Originally Posted by ironmangqtry cleaning the rod with a scotchbrite pad before wiping it with acetone. The acetone wipe is good to clean up after the brushing too.
Reply:Originally Posted by MinnesotaDaveI only have questions at this point.Aluminum and at 130 amps but not full pedal - what thickness is the material?  Must be quite thin.What size filler rod?Is there a reason you are wire brushing the heck out of it?  Is it new material of a known type?
Reply:Here's another theory... you know how at the very start until the light comes on and you can see where the tip of the tungsten is you some times have a little to long of arc length before you can get it down close?  Could it be that the higher arc voltage associated with the longer arc causes a temporary over heating of the still developing puddle from the first dab that acts to vaporize off an extra little bit of the magnesium at the start of the weld? And at the end of the joint where your angle is off and is kind of pointing toward empty space because your right at the end of the base material and the arc get's longer and unstable because it's trying to curve back toward it's electrical path you get the same thing happening.  Now that you got me thinking about it I've had more trouble with that smut at the very ends of welds than at the start.
Reply:Zmechanic,Due yourself a favor and throw that standard collet body in the trash and get a gas lens for your torch.   And get the biggest diameter cup for it that's available (I have a #8 on my WP-20).   I think you'll be amazed at the difference it makes.  The shielding gas flow out of it is way smoother and more resistant to out side forces from moving air and allows you to run more of a tungsten stick out so you can better see what your doing with out losing shielding coverage.