questions from a newbie

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First-Time Welder. Hobby applications.primarly sheet metal / floor pan replacement on my old  Chevy. Just purchased a Powermig 180C.The instruction manual says to set the gas flow from 30 to 40 cubic foot per hour.  The gauges sent with the unit are calibrated in pounds per square inch.  What is the conversion from PSI to CFH on a 180C ?  How do I know if I have too little gas flow , or too much gas flow ?Should I go to my dealer and purchase a flow meter to connect to  the gage set provided ?I am using the .025 non-core wire and 75/25 mix, and I am having to run the amps two positions higher that the chart recommends to keep the wire from going "pop-pop-pop" . Polarity is set to (+).A C Voltage measured with a digital volt meter at the power cord connector is a steady 240 volts AC so the garage wiring is not dropping voltage.I've been practicing on 16 gauge scraps , and the beads are a little "fat" so far, but I may be moving too slow.   So far, I'm encouraged that I can do this... LOL !!!Don
Reply:Instead of turning up your amps, try slowing down your wire. It sounds like the pop-pop-pop could be from too much wire speed. Keep trying different combinations until the wire flows smoothly into the puddle and it sounds more like frying bacon.30 CFH seems awful high, unless your welding in the wind.Do a weld with no gas. See how crappy that looks?  Turn your gas down until your welds start to look like that, then adjust it up a little 'til they're clean again.
Reply:BOTH gauges read in PSI?  It's been a long time since I hooked up a Lincoln MIG, but they use to have to low pressure gauge calibrated in CFH, just like the Millers/Hobarts.  The high pressure gauge for reading tank pressure should be in PSI, of course.  There is no "conversion" unless you do some complicated math knowing the exact size of the orifice that the gas is flowing through, which is why most have this done for us and just have CFH on the gauge face, and usually marked with the orifice size.Amps are controlled by wire speed.  Play with the wire speed WHILE you are welding (arc on) and see what difference it makes.  Then, switch to a different voltage setting (with arc off if it has taps) and do that again.  Once in the right voltage setting, wire speed is usually the only thing you adjust for perfection.There may be several settings that actually make satisfactory welds, but you'll develop techniques that favor one over the other.With no wind, my low pressure gauge usually reads between 12 and 15 CFH.Last edited by MAC702; 03-18-2009 at 02:19 PM.
Reply:Oldcarfan did say gauges, didn't he. If they're both in PSI that just seems wrong. If the gauge nearest the output side (always on the left, I think) isn't in CFH, is it possible someone messed up assembling the  regulator unit?
Reply:By the way, a big thank you to the OP for including all the useful information about your process and settings that we need to eliminate other common causes of problems!
Reply:They are not both in PSIHe just be just readin' it wrongEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:I went out in the daylight ( dimly lit garage ) and you are all correct.The gauge reads L/min  and the smaller print reds cfh ( hidden by needle when at "0" )Thanks... guess I should get new glassesDon
Reply:I set my gauge to 25 l/mn cause I thought that was the CFH line- went through some gas that way I didEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge