No announcement yet.

Plasma cutter air pressure settings

  • Filter
  • Time
  • Show
Clear All
new posts

  • Plasma cutter air pressure settings

    I've got a 625 spectrum and I'm wanting to see what everyone has their air settings on. Basically how high does your air compressor go before it shuts off and what pressure is it when it kicks back on. The min air pressure is 90 and max 120 for this machine. I called miller and they said that I should not be going above 120, but I have a friend that's been running his air up to 150 for a long time and has never had any problems out of his 625 spectrum. Just wanting to see what everyone else is doing. Thanks

  • #2
    Why would you not just keep the pressure at or under 120 psi? If you want your shop air at 150, just put a regulator in the line to the plasma. They aren't that expensive.


    • #3
      Are we all on the same page? What does your friend mean when he says he 'runs his at 150?' I'm thinking he has a compressor with a designed tank pressure of 150 PSI. But any shop compressor should have a regulator that is adjustable for the tool being used. The regulated hose-to-machine pressure is independent of the automatic pressure switch that maintains a suitable tank pressure, which is typically higher than the regulated tool pressure, even at cut-in pressure.

      Miller is saying that their machine doesn't need any more than 90 to work properly, and that they designed it to safely use up to 120. Don't second guess them, especially on vague anecdotal "experience," when there is no reason to. Regulators are cheap, especially compared to price of compressors, much less plasma cutters.

      FWIW, I had set my regulators at whatever the median recommended pressure was for my Spectrum 375. I used it on several compressors, with tank pressures of 125, 150, and 175, but, again, that's independent of the working pressure, and only an indication of how much air I can uncompress and use for work before the compressor kicks on again.

      I've never seen a shop compressor without a regulator. Cheap handyman compressors even have them built-in, which is why you will typically see two gauges, one for tank pressure, and one for regulated hose/tool pressure.
      Last edited by MAC702; 09-28-2017, 06:57 PM.


      • #4
        I've got a spectrum 625 several years old, it has a built in adjustable regulator, two preset green hash marks at what Miller thinks the pressure should fall between (70-sh to 90-ish) and a manual. What's wrong with following Millers guide lines?

        I should add that the input is whatever the input is, 130 or so, but the cutting pressure is at or close to the recs.
        Last edited by Sandy; 09-28-2017, 06:57 PM.


        • #5
          Running a higher pressure isn't going to allow you to cut longer before having to stop so the compressor catches up. Increased stored volume or compressor output capacity does that.

          Is there a particular reason you think you need a higher pressure than is recommended by the manufacturer?

          I blew up a brad nailer a while back because I forgot to turn the pressure down. Cost me $80 in parts to fix it. I bet parts for the plasma cutter will be more costly.