Dumb Plasma Cutter Question.

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I recently purchased a Hypotherm Powermax 45xp and I'm trying to figure out the best compressor to pair with it.  As near as I can tell, it requires at least 6 CFM @ 90 psi, but up to double that when cutting at it's max capability.  I don't need a compressor for air tools or anything else for that matter.  I'm just a weekend garage warrior, but I don't want to put a limit on my new plasma cutter because I didn't buy a good enough compressor.  Logic says get one that will do at least 12 CFM, and it seems the sweet spot for most compressors is around 15 cfm, but these are giant machines I'll need to add another 220 circuit for.Am I on the right track?  Pony up the $2000 or so, add the 220 circuit and be done with it, or am I over thinking/over buying?If I'm cutting thinner material do I need to dial back the cfm of will the plasma system adjust, or is there even such a thing as too much air?Thanks in advance for your advice.
Reply:I use a 60 gal Husky single stage. It produces 10+ psi and is plenty for my Miller plasma. It is necessary to have dry air so plan how you will address that - cooler, long lines with drops, desiccant, etc. You dial back the amps and adjust air for thin stock.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:Originally Posted by brothernovI recently purchased a Hypotherm Powermax 45xp and I'm trying to figure out the best compressor to pair with it.  As near as I can tell, it requires at least 6 CFM @ 90 psi, but up to double that when cutting at it's max capability.
Reply:Originally Posted by wb4rtI use a 60 gal Husky single stage. It produces 10+ psi and is plenty for my Miller plasma.
Reply:[QUOTE=Jack Ryan;8824212]A typo?Yes, I’m sorry about that. Should say 10+ CFM at 90 psi. Thanks!Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:I have the 45XP. My compressor is a 5HP Ingersoll Rand with 80 gallon tank. I tend to cut 2 minutes at a time, then pause while setting up for the next cut. The compressor seems to start once an hour or so. I believe you want to have a big compressor if you are making a production run of cuts. For fabrication work, a smaller compressor will do fine.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:I have a problem with dialing back the air pressure, my hypertherm 65 and I think the 45 XP is the same.  If the air pressure drops below 80 PSI it will stop the plasma flow (no cutting), it also uses air flow after a cut to cool the consumables.  The fine cut consumables will consume less air volume but not air pressure.DIY CNC Plasma table USB BOB Price THCHypertherm 65Everlast PowerTig 255 EXTMiler 180 Mig13" metal latheMill/ DrillECT, ECT,
Reply:Originally Posted by acourtjesterI have a problem with dialing back the air pressure, my hypertherm 65 and I think the 45 XP is the same.  If the air pressure drops below 80 PSI it will stop the plasma flow (no cutting), it also uses air flow after a cut to cool the consumables.  The fine cut consumables will consume less air volume but not air pressure.
Reply:I have a Hypertherm 85 that I use for production CNC work, mainly 14 gauge with fine cut consumables.  I use a Champion 5HP, 175 PSI, 17 CFM compressor.  Important to also have clean dry air for the best cut.  If you can afford it I would buy once and cry once.  With our high inflation, chances are that it will maintain its value if you buy a high quality unit.Miller 350 DynastyMiller TrailblazerMiller 625 Plasma Lincoln Power MIGVictor oxy/acetyleneHyperthem 85
Reply:Originally Posted by Jack RyanThis is from the manual:Recommended gas inlet flow rate/pressure188 I/min (400 scfh) @ 5,9 bar (90 psi)I'm not an expert on compressor requirements but you are not going to need a continuous free air delivery of 400 SCFH. The duty cycle of the plasma cutter at max power is 50% so you can use a smaller compressor with a decent size tank but others will have to tell you how much smaller.You will need clean and dry air. I only use filters and condensation traps and I am happy with that - you have to start somewhere.Jack
Reply:thanks for all your thoughts.  I'm guessing no one has ever bought a compressor that was too big.. Just needed to verify.
Reply:Originally Posted by Willie B400 Scfh? I don't know what the S stands for, I'll assume CFH is Cubic Feet per Hour  or 6.6 Cubic Feet per Minute.
Reply:If you have a 110v twin cylinder oil lubricated compressor with a 10 gallon tank you will never have to wait for air.Ran that setup with my 45xp cutting and gouging the cutting edge off a 966 loader, no issues other than the pumps can start to pass oil when you run them continuous on a 40c day
Reply:Unless I'm missing something basic......It's worth remembering that the Powermax45 XP wants to see the incoming air at 85 PSI and air compressors are rated at higher PSI ratings than that.  For instance my 6.5 HP DeVilbiss compressor is rated at 21 CFM at 175 PSI. so it's going to provide 43 CFM at 85 PSI.As the recommended air supply for the Powermax45 is 400 CFH that's 6.7 CFM at 85 PSI.  Using my compressor as an example:  175 PSI at the compressor divided by 85 PSI needed at the plasma cutter = 2 CFM of 85 PSI air at the plasma cutter for each rated CFM at 175 PSI.  The cutter needs 6 CFM of 85 PSI air so you only need 3 PSI air at 175 PSI to provide it.  Given that this is all nominal figuring you ought to go higher but you surely don't need very much compressor to run that plasma cutter.......   Brothernov, where did you that it might need twice the 6 CFM?Best regards to all,LanceLanceMultimatic 255 w/MDX-250 EZ-Select gunHypertherm Powermax45 XPHeck Bevel Mill 4000Miller/Smith heavy duty torch set9" Evolution circular saw
Reply:Originally Posted by LanceRUnless I'm missing something basic......It's worth remembering that the Powermax45 XP wants to see the incoming air at 85 PSI and air compressors are rated at higher PSI ratings than that.  For instance my 6.5 HP DeVilbiss compressor is rated at 21 CFM at 175 PSI. so it's going to provide 43 CFM at 85 PSI.As the recommended air supply for the Powermax45 is 400 CFH that's 6.7 CFM at 85 PSI.  Using my compressor as an example:  175 PSI at the compressor divided by 85 PSI needed at the plasma cutter = 2 CFM of 85 PSI air at the plasma cutter for each rated CFM at 175 PSI.  The cutter needs 6 CFM of 85 PSI air so you only need 3 PSI air at 175 PSI to provide it.  Given that this is all nominal figuring you ought to go higher but you surely don't need very much compressor to run that plasma cutter.......   Brothernov, where did you that it might need twice the 6 CFM?Best regards to all,Lance
Reply:Originally Posted by DrooopyActually, you are missing something.  Same something I missed at work that cost me $$$ to replace a brand new compressor for a customer.Compressors are rated on the quantity of air they ingest and can compress to that pressure in 1 minute.  They are not rated for the quantity of compressed air they can output at the rated pressure.  You absolutely cannot use the ideal gas law on the output side.  8 scfm at 100 psi rating does not become 16scfm at 50psi. I have a really nice rotary vane Mattei that is overkill for my shop from when I learned this lesson.  24 scfm at 115psi.   My customer asked me to throw in a 100scfm at 15psi compressor as part of a package I was selling them.  I sold them the Mattei thinking it could keep up with their need no problem.   However, when I tested output (after shipping it to Alaska) at 15psi, i got 27scfm.Lesson learned.Sent from my SM-N986U using Tapatalk
Reply:As a teenager I did a fair amount of body work. I had a 1 HP 2 stage compressor with a 20 gallon tank. I used a series of extra tanks to improve storage.I later upgraded to a similar machine with 3 HP motor & bigger compressor. When the tank rusted a leak, I set the compressor on a 100 gallon propane tank that fell into my hands when new owners bought a house & they couldn't get the old supplier to pick up their tank. I had a homemade upright compressor.I could run a DA, a bit of sandblasting, paint, then I'd have to busy myself with something else while the compressor caught up. Much of my work was rust repair. While one rust hole or rocker was near ready for primer, another was in an earlier stage. It wasn't a great hardship to work around the compressor catching up. This is near true with plasma cutting.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 LanceRUnless I'm missing something basic......It's worth remembering that the Powermax45 XP wants to see the incoming air at 85 PSI and air compressors are rated at higher PSI ratings than that.  For instance my 6.5 HP DeVilbiss compressor is rated at 21 CFM at 175 PSI. so it's going to provide 43 CFM at 85 PSI.As the recommended air supply for the Powermax45 is 400 CFH that's 6.7 CFM at 85 PSI.  Using my compressor as an example:  175 PSI at the compressor divided by 85 PSI needed at the plasma cutter = 2 CFM of 85 PSI air at the plasma cutter for each rated CFM at 175 PSI.  The cutter needs 6 CFM of 85 PSI air so you only need 3 PSI air at 175 PSI to provide it.  Given that this is all nominal figuring you ought to go higher but you surely don't need very much compressor to run that plasma cutter.......   Brothernov, where did you that it might need twice the 6 CFM?Best regards to all,Lance
Reply:I haven't read all the responses but adding a 10 gallon expansion tank to a smaller compressor will be enough air to run the plasma. Good dry air is a must so pony up and buy a good dryer.
Reply:this is what I use on my CNC Plasma table for an air dryer, I have seen others on Youtube showing their mods to this and other water filters.  There is Kitty litter that is Silica gel that works great and is cheap.https://www.lowes.com/pd/A-O-Smith-A...tem/1000576415 Attached ImagesDIY CNC Plasma table USB BOB Price THCHypertherm 65Everlast PowerTig 255 EXTMiler 180 Mig13" metal latheMill/ DrillECT, ECT,