Hypertherm 600-Expanded Metal

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I was cutting some 3/4 #9 to make some covers for vents along the lower side of a pier and beam building.  The aluminum vents and thin wire screen have been no match for varmints  like raccoons, cats, possums, etc.    I was using 72 psi, and tried from 30-40 amps for settings. As I was cutting, the thicker part. where the metal crosses and makes an "X", I could see the metal melt and then behind the cut get sucked back across the gap and solidify. Did not happen all the time, but about 1/4 of the time.   Was my current to high/low, moving to fast/slow or my air pressure too low?  My air compressor output is set to 90 psi and it is about 100 feet to my plasma cutter. Should I increase my initial pressure at the tank to the line to 110 psi to account for the travel length to the machine?Thanks
Reply:30-40 amps for #9 expanded metal?  My Powermax 350 makes short work of 1/4" mild steel at 25 amps.What you've described can happen if you're moving too slow or the torch is too far from the material (1/16" is ideal).  It could just be from the shape of the material causing weird air flow around the material.Is that 72psi while cutting or static with machine idle?  Should be while cutting.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Thanks Duaneb55What you've described can happen if you're moving too slow or the torch is too far from the material (1/16" is ideal). It could just be from the shape of the material causing weird air flow around the material.----Well, I bet that is the prob.  I was "studying" the cut as I was doing it.  I will get a scrap piece out tomorrow and see what happens. I was moving much slower than when I cut 3/16" angle iron or flat plate. Maybe too much watching and not enough just doing.Is that 72psi while cutting or static with machine idle? Should be while cutting.---My 72 was while idle.  Guess that needs to be adjusted to.Okay, let me reload and check again.  Thanks for the reply!
Reply:Try lower power as well.Jim
Reply:Gee Jim thats what I like about my PowerMax 45 the unit has a Mode switch that provides a continous pilot arc whiich is great for cutting expanded metal.of course you still have all your other adjustments, but the unit will even warm you if your air presure isn't right.Co-Own CNC shop:Miller :1251 plasma cutter, MaxStar 700 TIG/Stick, & XMT 456 Multiprocess Welder.&  2 Hypertherm HPR260's Plasma CutterSorry I had a bad stroke but now I am back.
Reply:specter,The Powermax 600 also has a switch for cutting expanded metal.I think Jim (and he should) hit the nail on the head.  Faster travel speed and lower amp setting and I think the OP's problems will go away.72 psi air pressure, if measured at flow, sounds a little too high to me.  On my PM 600, I'd run between 60-65, maybe even a little lower.  Heck, even on the PM 1250 I'm between 60-65.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:To keep from doing multiple things at once and not knowing what adjustment worked the best, I tried turning down the power, first, to 20 amps.  I left the pressure alone.  Now, it cut cleanly, and I was able to move at a brisk pace and no "re-welding" where I had just cut.   Was I possibly heating the metal to a molten state over a wider area to a molten state than the stream of air was able to blow away, allowing the molten metal left over to rejoin?   Thanks for the help!  The expanded metal cutting feature is nice.
Reply:RTFM, it sez set it at 78 while the air is flowing and forget it .  David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David RRTFM, it sez set it at 78 while the air is flowing and forget it .  David