Gas pressure for MM210

admin

I realize that all things are not equal, but what is the recommended gas flow for the MM210? I get soot around my welds and not sure if it' gun angle or lack of gas flow. I set the gauge to 25 cfm with trigger pulled. snoboy
Reply:Kind of surprising, but I could not find a comprehensive recommendation for  shielding gas flow rate.  I think this is because it can be rather complicated based on the all the following variables:Welding process, nozzle diameter, nozzle length, diffuser design, nozzle to work distance, base metal type, amperage, arc length (voltage), shielding gas type, drafts, etc.Generally, if I'm starting out on a new machine welding steel, I'll start out around 15 scfh Argon for TIG, and 30 scfh Ar/CO2 for MIG.  Depending on the surface appearance, I'll try to reduce the flow rate and see what happens.  As I always say, more flow is not always good in welding, you can get turbulence that introduces air into the arc zone.I had to run an automated MIG weld in a very tight location, so I removed the gas nozzle and fixed up an auxiliary nozzle with a gas lens to come in from a different angle.  Because of this particular setup, I had to run the  Ar/CO2 up to at least 50 scfh.Did happen across an interesting table showing the flow rate (scfh) achieved for a given orifice diameter and gas type, at a pressure of 30 psig.http://www.thefabricator.com/Consuma...cle.cfm?ID=347
Reply:Thanks for the info Pulser. I have a few questions for you. 1) Is there not supposed to be any black "soot" to the sides of the weld? I'll go ahead and try using 30cfh and see if it helps. If it cleans up then I'll know 30 is ot too much flow.2) How critical is gun angle? I'm currently making up alot of "bracket" type stuff that doesn't always leave much option for gun angle. I guess it's just do the best I can at that point. I have come to the conclusion that welding IS all about practice, practice and more practice. 3) Can you give me a briefing on wire speed ie. Lets say Your welding with my MM210 and you are doing 1/8 in steel. With .030 wire and C25 gas the chart calls for a setting of 3/50. What sound or visual reference would make YOU slightly alter the wire speed up or down? (hope you understand the ?) If the bacon frying sound is slowing down do you speed up or  what do you do?  I know I need to start taking and posting pics of my welds so you guys can critique them. snoboy
Reply:Had you seen this other recent thread, it deal with some of what you're talking about.http://www.weldingweb.com/vbb/showthread.php?t=7266Black soot?  Would like to see some photos.  First, is the steel clean?  If there is a lot of soot, I would think its from crap on the steel.  Some deposit of dark particles is normal in MIG welding, it's composed of some of the metal vapors from the arc that have oxidized and condensed along the bead.  Even the cleanest stainless steel, TIG welded in a perfect atmosphere within a glovebox, will have of deposit of manganese oxide along the weld toes.As for gun angle, I can speak to spray transfer MIG, not too sure what best for short arc, but I use a slight push angle of about 20 degrees, to help flatten the bead out.  In a corner weld, like a fillet, the gun is usually equally pointed at each plate, so 45 degrees from both, unless the joint is horizontal, the point a bit more at the vertical member to fill and avoid undercut.Can't say much specific on wire speed, other than the stuff in the other thread, some others here a into short arc.
Reply:Excellent read, I'm printing it! Thanks again.