Mig setup

admin

Need a little help guys.  I have a Lincoln SP 175 and am going to be welding some .125 inch square tube indoors.  I have 75/25 gas.  Where would be a good place to start setting my gas gauges, wire speed and volts?  Thanks in advance for any advice.
Reply:Gas at 15-20cfh, set the heat at about 4 and the speed at about 4.5.  Start there, and move the speed up slightly first, then maybe move the heat down a bit on some practice pieces. Small adjustments, and only one dial at a time. You likely won't need more heat than that for 1/8" steel.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:RTFM.  And flip up the door to the wire compartment and notice the nice "Suggested Settings" chart right on the inside of the door.As Rojo mentioned, you usually set the gas flowrate to about 20 cfh (+/- a bit depending on if there is a draft or not).And as he mentioned, change ONE thing at a time and run some practice beads/joints with the material you plan to work with.Rojo, those Lincoln machines use letters for the voltage.  Miller uses numbers for the voltage.    A MM175 and C25 gas  for use on 1/8 inch thick workpieces recommends voltage 4.5 and wire speed of 85-50 depending on which wire diameter is being used.Rojo didn't ask or mention the wire diameter.  Either 0.025 solid 'MIG' wire or 0.030 solid 'MIG' wire should work and be relatively available.  You could use 0.035 solid wire in an SP175Plus (the machine has enough 'snot' to run that size), but it's a trade-off on being able to do thinner-vs-thicker material as you change wire diameters.  Each change in wire size (with that machine or similar ones) 'shifts' the thickness range of the workpiece(s) about one gauge size.  ie: 0.025 L-56 wire and C25 gas is recommended for 24 gauge to 12 gauge, 0.030 L-56 wire and C25 gas is recommended for 22 gauge to 10 gauge, 0.035 L-56 wire and C25 is recommended for 20 gauge to 3/16 inch (one size 'up' from 10 gauge).And all that/this information is in your manual AND on the nice door chart.SP175Plus for 12 gauge (0.105 inch thick) work and 0.025 L-56 solid wire and C25 gas lists a recommended setting of E-9 (volts-wirespeed/amps) [max recommended thickness using that size wire].  Using 0.030 wire and C25 gas, recommended settings are between G-9 and H-9.5 (those are the recommended settings for 12 gauge/0.105 inch and 10 gauge/0.135 inch respectively).  You can look up the settings if using 0.035 L-56 wire, they're on that nice doorchart and in the manual.  If your machine is an SP175-T model, the recommended settings from the manual/doorchart would be E-10 using 0.025 L-56 wire and C25 gas (max recommended setting for thickness 12 gauge/0.105 inch with that 0.025 wire and C25 gas), and E-7.5 for 0.030 L-56 wire and C25 gas (12 gauge to 10 gauge same recommended settings).If you have a "T" machine, do NOT-NOT-NOT change the voltage knob/setting while welding.  See the manual.If you have a "C" model machine or the SP175Plus, you -can- change the voltage while welding.  The best laid schemes ... Gang oft agley ...