Difference b/t .030 & .035 mig wire, help please.

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Not a mig expert in the least here, so please go easy.  I've been using the .030 Lincoln L-56 mig wire from my MM211 on a 230v circuit.  80%-20 AR-CO2 (airgas) mix. The steel I'm welding is super clean 3/8" flat bar and some channel iron. I understand that a "bigger" sized wire means "more" amperage output theoretically.  My question is, with that Miller 211 and thick steel, will I see or get better welds with a thicker diameter mig wire size of .035?Reason I ask, when I used to have a Miller 140, going from .030 to .035 seemed to be a mistake. The welder seemed too weak with not enough "juice" to really benefit with using a thicker wire.  I just wonder if the 211 would perform better on thicker steel with a thicker wire size?Should I just stay with .030 or would it be beneficial to switch to .035  out of my new MM211  on thicker soft steel? Thank you. "Hey I didn't come to look and learn, I came to turn and burn.... If I can't light up, I'm gonna light out!"-JodyIdealarc 250 "Fatman"MM 252MM 211 "Little boy" Victor Torches
Reply:Yes, moving up to 0.035" wire with your MM211 will be beneficial.  According to Miller's weld calculator, 0.030" wire is good for about 120-130amps of current carrying capacity and is therefore suitable for welding up to 14 gauge material. 0.035" wire is listed as capable of carrying up to 220amps of current, which is suitable for welding up to 3/8" thick material.http://www.millerwelds.com/resources...calculator.phpSpecs for the MM211:150 Amps at 23.5 VDC, 30% duty cycle (230 V)Welding Amperage Range 30 - 210 Amps Wire Speed 60 - 460 IPM (1.5 - 11.7 m/min) Without enough current, there isn't enough heat delivered to the puddle to achieve good fusion between the puddle and the base metal.  What ends up happening is that the puddle just sits on top of the base metal, without achieving proper fusion.  You can try tricks to extend the range of suitability; like pre-heating the weld area, beveling the weld joint on thicker material, etc.  But the odds are long that you'll achieve a sound weld throughout the entire length of the weld deposit.  Miller rates the MM211 as capable of welding 3/8" material.  Perhaps with fluxcored wire, but it's performance at rated output(150amps 30% duty cycle) is really only capable of reliably welding 5/16" thick material with solid wire.  yes, you can hit 210 amps and 23.5 volts, but that's at max output.  Which drops off rapidly as the unit heats up, until it shuts down to cool off.So, depending on what you're welding, you might want to consider other processes(Stick, TIG, or perhaps, self shielded fluxcore) or another, bigger MIG machine for solid wire MIG welding on 3/8" thick material.  You could probably achieve consistently reliable welds on some short fillets on small sections of 3/8" material.  But if you're welding large pieces of plate, using long weld beads, you're asking a lot from a MM211.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:A Dab, thank you for taking the time to explain that!   Makes sense and I appreciate it.  Now I'm bumbed because I just spent $45 on a new 8" roll of .030.  I wish I had bought the .035 instead!  I don't do much mig welding and that .030 is gonna last a long long time. "Hey I didn't come to look and learn, I came to turn and burn.... If I can't light up, I'm gonna light out!"-JodyIdealarc 250 "Fatman"MM 252MM 211 "Little boy" Victor Torches
Reply:I think the .030 wire is better suited for your machine.  It take a lot of welder to efficiently utilize .035 wire.  I would have to disagree with Dab on the limits of .030 wire.  I would say it is capable of doing everything your machine was intended to do.  I use to use .035 for almost everything due to it being the primary wire we used at work.  But, after Dan's praise for the .030, I began trying it and I have been duely impressed by the wide working range of it.  I am more impressed with it due to it being a far superior thinner metal wire and it is no slouch in the 1/4 - 3/8 inch arena.
Reply:In response to the OP's original question...The difference is .005 inches.With that said, I agree with Scott.  The .030 wire is better suited to the machine you are using.  As mentioned, Dan (although a big Hobart fan) swears by the .030 wire in the 200A +/- range machines.Really a case of matching the wire with the machine.  In my HH187 I run .030.  The MM251 stays loaded with .035 and when used, I'll hang .045 on the XMT/feeder.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:I too use nothing but .030" in my Lincoln PowerMIG 200.I also only use .023" in my smaller machines (SP125, SP135, and 170T).I just welded a project the other day that was all 1/4" to 3/8" with the .030" and it was no problem.http://all-a-cart.comWelding Cart Kits and accessories
Reply:OK,  I see two different questions being addressed here;1 - The OP's question paraphrased, "Which wire is better for welding 3/8" thick mild steel?  0.030" or 0.035"?2 - What diameter wire runs better on a MM211?  0.030" or 0.035"?In answering question #1, I stand by my original recommendation.  0.035" wire is better for joining 3/8" thick mild steel.  Based on Miller's specs for the MM211, you're asking alot of the machine to deliver enough current and voltage to do the job properly on 3/8" material, using short circuit transfer.  (let's not debate getting spray transfer from the MM211 here, that's a whole other topic)Airgas's website has some good info on this, and so does Lincoln Electric's website.  http://www.airgas.com/content/detail...=7000000000143http://www.lincolnelectric.com/asset...L-56/c4200.pdfWith regards to question #2, yes, 0.030" probably runs better on the MM211.  The current required to weld with 0.030" solid wire is right in the 'sweet spot' for the MM211 amperage range.  I'm sure the arc is at it's best performance in that amperage range.  But that doesn't mean "average joe" can make sound welds with 0.030" wire on 3/8" thick mild steel.We can debate the max thickness it's possible to join with 0.030" wire; with short circuit transfer.  I stand by my recommendation that most people should limit themselves to 14 gauge, with 0.030" wire.I don't rely on 0.030" for anything thicker than 1/8" in short circuit transfer and mixed gas(75/25).  I won't recommend that a novice "push the envelope".  Better if they just step up to the next wire size and weld with the proper settings, using wire that delivers the right amount of current to the weld puddle.(not sure if the OP is a novice or not, I just respond to all questions as if they are.  Since some other person, who is a novice, might read what I wrote and take it as gospel)Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:I'm not disputing the quality of your work ZT, so keep that in mind. I've seen pictures posted here of your work, and I'm impressed.  But just because you're capable of extracting 100% of what's possible from your machines and 0.030" wire, doesn't mean that most people can.  And that goes double for novices.I don't have the specs to hand, but if your powermig200 is similar to Lincoln's current powermig 216, then it's a more capable machine than the Millermatic 211.  Higher duty cycle at higher rated output, and capable of higher wire feed speeds.  But I'm speculating based on Lincoln's data for the powermig216.   Originally Posted by ZTFabI too use nothing but .030" in my Lincoln PowerMIG 200.I also only use .023" in my smaller machines (SP125, SP135, and 170T).I just welded a project the other day that was all 1/4" to 3/8" with the .030" and it was no problem.
Reply:Take a look at the attached graph.  I pulled this from Lincoln's GMAW guide book; see page 16 in the link I put in my previous message.The black horizontal line represents the maximum wire feed speed that the Millermatic 211 is capable of, approx 460 inches per minute.The two vertical red lines indicate the maximum current that 0.030 and 0.035" wires can deliver to a weld puddle, at 460 inches per minute wire feed speed.  I estimate that's about 180 amps for 0.030" wire, and about 235 amps for 0.035" wire.How much current is needed to join 3/8" material?  I don't know the exact answer.  But I do know that the more current/amperage delivered to the weld puddle, the more heat delivered to the weld joint.  More heat equals greater likelihood of complete fusion from the root of the joint out to the toes of the weld.If I'm welding thick material(over 1/8" thickness), I'll take all the heat I can get, up to the point of burning through, of course.Last thought, notice in the graph how all the curves get steeper and steeper as the current gets higher.  All wires reach a point where they can't carry any more current.  Turning up the wfs(in short circuit transfer) just piles more metal onto the weld puddle, but doesn't deliver any more heat to the joint.  This is why you can't weld everything with 0.023" wire.  The pros know this through experience(I hope). Attached ImagesLast edited by A_DAB_will_do; 04-06-2012 at 05:07 PM.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector