Jody's (WT&T) suggestion doesn't seem right

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He posts a method for calculating wire feed speed that gives results way off from my Hobart door chart. 1amp for every .001 thickness. So .125 would be 125 amps. Then for 030 wire you double the 125 which gives you 250 ipm. Squeeze your trigger, measure how many inches you get in 6 sec, add a zero and that number is where your speed is set.Well, according to the door chart I should be at 5, which equals 185 ipm using the 6 sec method of calculating. Yet the Jody method says use 250. Is that nonsense or have I missed something? So far I'm sticking with the door chart.Last edited by JD1; 02-08-2015 at 12:21 PM.
Reply:Jody is a pretty good welder. could be just differences in machines. I always set mine by the sound anyway. My door chart is used as a starting point but I seldom land there in the end.Miller Multimatic 255
Reply:Well rules of thumb are pretty generic, just to be used as a guide and not for exactness or specifics. Each solid wire diameter has it's own characteristics as far as ipm's per amp as long as you realize those are also pretty general in nature. You have to have take the wire size you are using at the time then have an idea of it's speed/amps characteristics and use that. For instance .030 is normally listed as about 2 ipm per amp. Once again, that is a generalization. It may start out as 2 ipm per amp initially but as the feed speed/amps increases the wire becomes more saturated (current saturation) so as you increase the wire speed at the upper end the ratio of speed per amps becomes less and less untill you might be just piling on filler without increasing the amps a lot more. Each manual generally has a wire speed vs amps chart in there somewhere. The feed speeds to amps ratio are a curve and not lineal.Last edited by Sandy; 02-08-2015 at 01:14 PM."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Amperage, or current are also influenced by voltage, or pressure. Higher speed means shorter arc length, and less resistance, lower voltage, which the machine will correct, and higher amperage. Faster is hotter.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Originally Posted by Louie1961Jody is a pretty good welder. could be just differences in machines. I always set mine by the sound anyway. My door chart is used as a starting point but I seldom land there in the end.
Reply:Originally Posted by JD1Maybe I'll try that. Left hand on the dial, right hand on the gun and see whether I end up close to Jody or close to Hobart's chart. Is there any noticeable penetration difference with wire speed change or do you just get a different size weld assuming travel speed is the same.
Reply:Thank you. Very helpful.
Reply:I just had an interesting experience yesterday with my mig machine and wire, that is in "setting it".   I just finished a spool of .023 and put on a roll of .030.  I said to myself, "iI'll just leave the setting the same and see how far I have to turn the wire speed and heat up, as of course the .030 is slightly bigger in diameter so I anticipated having to turn both up a little to compensate for the extra wire mass.  So one would think any way.  Turns out, it seemed to melt the .030 (fine on the .023 settings (if not easier/hotter).  I deduced that there can simply be a quality difference in the manufacturing of the two different size of wires that could cause them to melt differently.  I suppose it could have been the machine, but not likely.  Weird.  Bottom line with setting the mig process is that all machines act differently as do mig wires (especially between different manufacturers - in this case both spools where from the same manufacturer.  Could of been a loose nut on the mig gun (me) but not likely; I've burn through thousands of spools of mig wire so I hope I know when the machine is set correctly and what it takes to get it set.Some kind of Big Blue constant current welding machineAnother smaller yet, Blue machine (it's got wire in it)
Reply:What I usually do is set the voltage and wire speed by the door chart, then adjust the wire speed by sound, and check for the amount of penetration. I often find it is over penetrating, so in that case I turn the voltage down one notch and readjust the wire speed based on sound. But I am self taught, so chances are I am doing it wrong Miller Multimatic 255
Reply:If you have a Hobart Handler 125, 135, 140, 175, 180, 187, or 190 trying to measure IPM of wire being fed is a waste of time.  Due to the design of these units, the wire drive motor feeds a higher rate of wire in a no-load state then it does in a loaded state. So, the measurement you took when you weren't  running a bead is going to higher then the actual IPM  when you're actually running a bead.ESAB Migmaster 250 Hobart Ironman 230Multimatic 215TWECO Fabricator 181i & 211iHH125EZ - nice little fluxcore only unitMaxstar 150 STH - very nice
Reply:Jody's way works, your door chart works. With Jody's way there is a balance between current and voltage. Lay down is faster forcing you to move along faster to produce a similar weld. As you move faster, you put less heat into the work. With your door chart there is likely a balance between current and voltage, as deposition and net heat are reduced, you will move slower to get a similar weld. Chances are you are there longer, more net heat goes into the work. Stickout will also influence amperage, and heat. It also influences voltage, but the machine will react to that.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Originally Posted by DanIf you have a Hobart Handler 125, 135, 140, 175, 180, 187, or 190 trying to measure IPM of wire being fed is a waste of time.  Due to the design of these units, the wire drive motor feeds a higher rate of wire in a no-load state then it does in a loaded state. So, the measurement you took when you weren't  running a bead is going to higher then the actual IPM  when you're actually running a bead.
Reply:Originally Posted by JD1So the no load measurement of 185 is going to drop even further below Jody's 250 when running. Interesting on the mechanics of the Handler.Makes all kinds of sense. I did run about 2 numbers higher than the chart an hour ago due to southpaw's post which might have put actual ipm in Jody's range although I didn't actually measure it. The sound was harsh and the wire was stubbing so that showed me where not to be.Edit: Curiosity got the better of me so just now I went back out and measured wire feed at the 2 numbers higher. It was 275 ipm, which with the load deduction mentioned above might put it at Jody's 250. As I mentioned, it was not a good setting. I think I'll stick with methods mentioned in this thread and the door chart.
Reply:i am always hotter than the door chart. i usually set for 1/4" when welding 1/8" typically 21 volts and 375 ipm with .035Millermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:1 amp per thou: actually works if you want to overpenetrate, on a flat butt joint, with TIG, on mild steel. For everything else it's just a wild ballpark. The key is to memorize a few good adjustments to add to the rule. eg "Plus 10% for a fillet." or "Minus %25 for an open root on 304 SS pipe." I'm a bit of a hack with MIG, but like Sam said, always hotter than the door chart. Ever tried spray transfer?SqWave 200Millermatic 190Airco 200 ACHypertherm PM45Boice-Crane Band SawVictor O/A
Reply:hobart or jody.... um jody!VictorPraxairAir LiquideMillerLincoln Electric
Reply:Mileage with the door charts & machine recommendations vary, but it's better than nothing to start off with. When you get into the weeds with welding it all gets down to how much heat you want and for mig welding, wire consumption is the easiest way to get there. So I choose the heat, then the wire size, and then follow the volt recommendations for the wire size at that speed.For checking wire speed, I do a couple of three second pulls on the trigger with any run-in wire settings shut off. When you get deep into a wires capacity you start to use more wire for a given power so you move up in size & power.If you have something like Dan's talking about where then test & use speeds aren't consistent you'll just have to work through that by trial & error.As for the charts? Sometimes things get lost in translation like when I found a real strange number on the neighbors machine (welding at recommended 1/4” setting was a complete bust)...Good luckMatt Attached Images
Reply:For some MIG units, especially more advanced inverter units and I suppose transformers with some more advanced circuitry, they feature a slow "run in" of the wire to help prevent porosity at the start and incomplete fusion at the weld start. The drive motors don't "amp up" until an arc is sensed, so trying to squeeze off the gun without welding to figure your wire speed doesn't work well.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Good info here! I think people get caught up with trying to get their settings just right, when you really just need to find a setting that works for you. If you use a lower ratio, you have to move slower, higher ratio needs to go faster. There are other benefits other than speed in faster and hotter welding. It also REDUCES the total amount of heat put into the workpiece, and thus can result in less warpage or distortion. That's why on a lot of production lines, you'll see welders using spray transfer welding on sheet metal. Less distortion and goes much faster.John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker