What Mig Voltage for 3/8"

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About what voltage do you run for just a regular single pass Mig filet weld on two pieces of 3/8 mild steel.  Im buying a smaller mig for 3/16 work but if I have to put some 3/8 together I don't want to have to roll my 350amp (haven't got it in yet) across the shop to do it.  Im looking at some duty cycles which go by amps and volts and would like to know what people run.
Reply:About what voltage do you run for just a regular single pass Mig filet weld on two pieces of 3/8 mild steel.
Reply:Haha, well i have the powermig 350 ordered. Can't wait to get it in.back to the question,C-25 with .035 solid wire probably. my bad
Reply:I pulled this off the lincoln site on the Powermig 215, seems a little odd on voltage though. I thought the higher the V the more Amps your putting out?? Are those numbers right?215A / 22V/ 30% 190A / 23V / 40% 170A / 24V / 60%Either way, I was thinking about the 215 if its big enough.
Reply:Amps = wire speed.for .035 wire, it takes 1.6" of wire to draw 1 amp, so 160 ipm would be about 100 amps.  320 would be about 200 amps.  I set wire speed first (amps) then adjust voltage for the best arc.1" per minute = 1 amp for .045 wire2" per minute = 1 amp for .030Those specs are max, it shows the machine is made for short arc, and not spray.  It might, but ......Most lincoln mig welders have a chart inside the door.  I have a wirematic 250 and the chart doesn't go up to 3/8, but it sure as he11 will weld that and more.DavidLast edited by David R; 06-22-2008 at 09:40 PM.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Not exactly sure what you are trying to accomplish with this info as it's some what dependant on the machine you plan on using.My MM185 lists for 3/8, c25 .035 the #6 tap (maxpower) and a wire setting of 80 on the dial. From Miller's chart it looks like about 185-200 amps and about 23V. To me that amps and volts have no real meaning as I don't set my machine that way.Lincoln's chart for the Powermig 215 doesn't list a setting for 3/8 with .035 and C25. They list one for .045 C25, Tap G (max power) at a wire setting of 250. Again it looks like amps/volts have little to do with how you set the machine since the settings are not listed in amps and volts. ( I know that they have meaning but the machine doesn't use that as how you dial it in)It sounds like you are trying to make a small machine do the job of the big one and I doubt that it will do what you want it to. No matter what the duty cycle is you will not get a small 3/16" max mig to run 3/8" in one pass. Both my MM185 and the Lincoln Powermig 215 both look to be maxed out on power and have the wire speed cranked to almost max to do 3/8" in a single pass. You won't get good penetration on a smaller machine to do 3/8".
Reply:I think what you're doing is trying to get an idea of particular machines ampacities and duty cycles as well as compare that to a metal thickness to see if it will perform the way you need it to. In this case you chose 3/8ths as a guide. Dave gave some numbers for IPM to amps for wire sizes. There' another ruff (real ruff) guide for amps needed per inches in thickness. Keep in mind they are for near full pen and single pass and probably across an average of operating voltages not taking any individual machine into consideration. That's why I said real ruff.  For solid and C25 it takes ruffly 1 amp per .001 inch. So you can see using this guide 1/8th material would need 125 amps. Those same numbers would indicate you need 375 amps for 3/8ths then for single pass.  Using Daves numbers a PM 215 has enough wore speed for 375 amps but not enough backbone. Again single pass application. More than likely for 3/8ths you will be relying on joint prep and design to acheive acceptable results. For things like this you really need to see the actual door chart for a 215, convert their recommended settings to amps then try and glean out a duty cycle at those settings.Another thing you would have to do is decide whether by 3/8ths you mean some 3/8ths, a lot of 3/8ths, mostly 3/8ths, production 3/8ths and so-on. It wouldn't be fair to the machine to put it on a full diet at it's top end. The Powermig 215 and the MM 212 are pretty much mirror images of each other with a few exceptions. Any info you dig up on one pretty much applies to the other. The power mig has a higher top end.
Reply:Sandy your right on track with me.Not trying to make a small machine do the big boys job, just seeing if it can get itself out of a bind "every once in a while". Like I said if I have a little 3/8 to weld I don't want to have to pull my 350amp off of its present job (loosing productivity) to go take care of it.hmm.  might be asking too much from the 215. DSW seems to have the info we're looking for like Sandy stated. Do you know the recomended settings for 1/4" under the door of the Lincoln 215 or Miller.I think we could figure up the duty cycle atleast on 1/4" if I had that.
Reply:Ok Sandy's explanation made sense after reading it.Millers info on the MM212 shows tap #4 (out of 7 I believe) wire speed set on 60 for .030, #4 /48 wire speed for .035 using c25 for both. Looks like about 60% duty cycle @ about 150 amps 18V.http://www.millerwelds.com/om/o232384c_mil.pdf Thickness Chart on  Millers Pg 22-23Power curves on  Millers Pg. 12Lincoln's shows tap G wire speed 500 c25 1/4" .035 or tap G wire speed 250 C25 1/4" for .045.http://content.lincolnelectric.com//...r/im/IM828.pdf  Thickness Chart on PDF Page 18 just before Lincoln's C-1 section.
Reply:hmm. might be asking too much from the 215.
Reply:I just looked in the door of my wirematic 250.  It has a max of 5/16", 20 volts 360 ipm, C/25.  It goes up to 29 volts and 600 ipm.  Go figure.360 ipm .035 wire /1.6 = 225 amps give or take a few.It will spray weld (I have done it), but the gun would not hold up for long.I welded shanks on a 3/4" excavator bucket with that machine.  I did NOT preheat the cutting edge and one of the 5 shanks broke off from lack of penetration.  I stick welded the new one on.  The rest of the shanks stayed.  This was one of the few things I welded that didn't hold.  Its not the machine's fault, just the operator. DavidLast edited by David R; 06-23-2008 at 06:30 AM.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:DSW. so are you saying for 1/4" the miller will run on tap 4 wire speed 48 with .035 wire.You came up with 60% duty cycle which is fine. Seems like it could handle quite a bit of it.My question is, how did you figure up the duty cycle. Might be a dumb question but I was always wondering how you do that when your not looking at the max output of the machine the way Lincoln or millers chart say.
Reply:Yes for the MM212 those are the setting Millers manual listed.As far as duty cycle part is WAG and part is trying to read between the lines with the info given. Looking at the two tables in Millers book I'm sort of reading about where those settings would fall. Once I had an idea how many amps I THOUGHT they were saying it was using I went to their duty cycle chart and just plugged in the amps. It's not the most accurate way most likely, but it should be close enough for what you are trying to do.Part was looking at the power curve for tap #4. at a wire speed of 48 out of 100 that should put me approximately in the center of the curve. Then I used that to get an idea of about how many amps this seemed to be. It seemed  to match up with some of the info I had seen looking at some of the other info like the graphs for my MM185 that I had looked up earlier.Basic common sense says that 1/4" on a 3/8" rated machine should be ok on a regular basis. With the exception of my original little 110v mig I almost never run into duty cycle issues, but I don't do production welding either. If you are planning on pumping out foot after foot of continuous 1/4" then I'd go bigger, but it doesn't sound like that's what you plan on using the machine for.
Reply:Pretty much what all the nice folks already said.For 3/8 inch steel, single pass full penetration weld would be roughly 375 amps.So a 210/215 or a 175/180 class mig machine isn't -quite- enough oompf for a single pass on 3/8 steel.  Double "V" prep and at least one pass on each side and those machines can probably do the job.  On an intermittent 'make-do' basis, because that would be running those machines pretty much flat-out, and the duty-cycle on all/most of those machines flat-out is around 20-30% at best.btw, when the amps output goes up on a machine, the voltage usually droops.  Sort of think of it as the more load (amps) you have on a circuit, the more the voltage sags/droops because of all the amps being used.Moving up in machine size/class to the 250/255 machines, and they can do the job.  PowerMIG-255 can do 250 amps at 26V for 40% duty-cyle, and maxes out at 300A at a lower duty cycle.  But you're looking at 0.045 wire (Innershield-FCAW or Outershield-FCAW-G with CO2) and running close to flat-out.  Or 0.045 solid wire and spray transfer (using 98-2 Ar-O2 or a low CO2 mix like C5 or C10) and again close to flat-out.Regarding duty-cyle, Miller has charts showing the increase/decrease in duty-cycle for the decrease/increase of the output amps.  At least on some of their models.  They also have charts for volts/amps at the various settings for soem machines.  All that info is in the manuals for the different machines, available right off the Miller website.
Reply:Originally Posted by David RAmps = wire speed.for .035 wire, it takes 1.6" of wire to draw 1 amp, so 160 ipm would be about 100 amps.  320 would be about 200 amps.  I set wire speed first (amps) then adjust voltage for the best arc.1" per minute = 1 amp for .045 wire2" per minute = 1 amp for .030Those specs are max, it shows the machine is made for short arc, and not spray.  It might, but ......Most lincoln mig welders have a chart inside the door.  I have a wirematic 250 and the chart doesn't go up to 3/8, but it sure as he11 will weld that and more.David
Reply:185tsw, yes those #s should be good on any machine.   My SP100 has letters and #s on the knobs.  I sill have to look on the door to see where to set it.    I got this from miller or ESAB.  I don't remember the conversion for .023.   DavidReal world weldin.  When I grow up I want to be a tig weldor.