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  1. #1
    Join Date
    Feb 2009
    Posts
    107

    Default Plasma air supply.

    Has anybody used a small plasma cutter on a portable twin stack type air compressor.
    I use a tall upright in my shop but I want to be able to take and use it away from there.
    The cutter uses 65 psi @ 3.5 cfm. Hitach has a portable 2hp air compressor that shoots out 90 psi @ 4.0 cfm, so for small short cutting spells I thought it might work quite well.
    Does anybody have a past or present situation like this.
    Thanks for any help.

  2. #2
    Join Date
    Oct 2006
    Location
    Cleveland, Ohio
    Posts
    38

    Default

    The specs say it will work, but watch the amount of time that the compressor pumps. I try not to pump over about 50% of the time so you don't fry the compressor.

    Cheaper to let the pump cool than to buy a new one.

  3. #3
    Join Date
    Dec 2007
    Location
    southern California
    Posts
    1,783

    Default

    The smallest compressor I have effectively run with my Powermax 380 was an Emglo gas powered twin-tank 2-cyl single-stage 125 psi compressor that spec'd at about 10 cfm. I still had to wait for it some times and it pumped alot, enough to overheat it a few times during the day. I was demo-ing a steel stair case, cutting alot of 16 ga sheet up to 1/2" plate.

    My other compressor, a gas powered 30-gal 2-cyl 2-stage 175 psi that specs about 12-15 cfm has no problem supply air to the plasma under hard use. I've also run 3 sanders at the same time with it.

    By contrast, the little Porter-Cable pancake compressor and the bigger Makita 5200 I have, both have a very tough time keeping up with the plasma even for just light use. Not enough air from either of them. The more air the marrier. )
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  4. #4
    Join Date
    Nov 2008
    Location
    Colorado Springs
    Posts
    274

    Default

    How about getting yourself a bottle of Nitrogen for the rare offsite cutting projects.

    That is the alt. to compressed air.

    Remember, the customer always pays, you can rent the bottle from your LWS when you need it.
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  5. #5
    Join Date
    Dec 2009
    Location
    Northern California
    Posts
    179

    Default

    Quote Originally Posted by 1havnfun View Post
    How about getting yourself a bottle of Nitrogen for the rare offsite cutting projects.
    I have a small HyperTherm Powermax 30 Dual Voltage unit.

    It has worked well with a large 80 gal, 7HP running compressor in the shop. But when I have gone mobile to a remote location, I don't have a gas powered compressor in our rig. Just a generator which can run my Miller DVI or my Plasma cutter on 220 but not at the same time. This is the great thing about either unit since they both run on 110 but it limits their max ability.

    I got a a large bottle of Nitrogen and the new Victor gauge set and the really cool thing is that I hardly even need the filter inline. The Nitrogen is so much cleaner and drier that I love using it instead of compressed air!

    I can usually cut at least 10-12 pieces of 1/4" steel sheets into 1' squares with a bottle and still have gas to spare! Sometimes I forget to hook up the compressed air back in the shop and run the Nitrogen instead!

  6. #6
    Join Date
    Apr 2009
    Posts
    19

    Default

    I would also like to run a plasma cutter off either dry nitrogen or a high pressure dry compressed air bottle. I can get a nitrogen bottle from my LWS but they don't know what kind of regulator I willl need to run. The cutter will be a spectrum 625 or equivalent. What are my options for a regulator that can output at least 6 scfm @90 psi? Also, if you had to choose, would you go with air (extra cut capacity?) or nitrogen?
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  7. #7
    Join Date
    Aug 2006
    Location
    Plainview, TX
    Posts
    334

    Default You need air storage

    I have a HT Powermax 1000 G3 that is supplied by a Dayton 1.5 HP 2 cylinder compressor. It supplies 5.7 CFM @ 90 PSI. The original twin hotdog tanks, 9 gallon, rusted out years ago but has been replaced with a single hotdog tank of 12 gallon capacity. However, I also have a 40 gallon LPG tank from an Oliver Tractor. With the tank capacity, I can run extended cutting while using the plasma torch. Having pressure is all good, but what you are needing is volume.
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  8. #8
    Join Date
    Apr 2009
    Posts
    19

    Default

    Quote Originally Posted by flukecej View Post
    I have a HT Powermax 1000 G3 that is supplied by a Dayton 1.5 HP 2 cylinder compressor. It supplies 5.7 CFM @ 90 PSI. The original twin hotdog tanks, 9 gallon, rusted out years ago but has been replaced with a single hotdog tank of 12 gallon capacity. However, I also have a 40 gallon LPG tank from an Oliver Tractor. With the tank capacity, I can run extended cutting while using the plasma torch. Having pressure is all good, but what you are needing is volume.
    Thanks for the advice. I looked into lpg tanks and found out they have a working pressure around of around 240 psi so no concerns there.. A couple 100 LB cylinders should be enough. One question with the smaller compressors, what kind of flow rate are the regulators usually good for? I'm looking at a Makita 5200 and assuming the actual flow requirement for a spectrum 625 is going to be around 12 cfm since most on here are advising to double the Miller recommendation before the compressor will "keep up".
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    Diversion 165

  9. #9
    Join Date
    Aug 2006
    Location
    Plainview, TX
    Posts
    334

    Default Again, you are needing Volume

    The specified flow on the plasma cutter is spot on. The Spectrum 625 does not require 12 CFM. My HT PM1000 needs just over 6 CFM. Now, if I depended on the original tanks and the flow capacity of the compressor, it would run out of air in 5 secs. Because I have an AIR RESERVE, I can maintain the required flow needed to the plasma cutter. My compressor runs a longer cycle building back up the reserve, but it does not run constantly. For extended cutting, yes, I will have to let the system catch up, but then the cutter doesn't have 100% duty cycle at max output, it's more like 60%. If I was getting another compressor, I would get a 3HP with a 60 gallon tank with 10+ CFM at 100 PSI. At the same time, I would keep my added storage tank and try to find another to go with it.

    The reason folks say to get a compressor capable of 12 CFM for a 6 CFM demand, is because that compresssor will be on a large capacity tank and will be able to cycle on and off instead of running constantly. I'm getting by becasue I have storage capacity even though my compressor technically is 1 CFM short on output compared to the required CFM input to the cutter.

    Look at the real estate in your shop you're willing to let the compressor occupy. Then go get the biggest compressor that will fit in that space. Make sure your disconnect or breaker panel can handle the load you're going to put on it. Make sure you're getting a compressor that is rated at 3600 RPM or even better at 1800 RPM. Compressors that are using high speed motors, turning 4000+ RPM or HP at an over speed RPM are not worth using.
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  10. #10

    Default

    I'd just make sure you have a good filter/water separator on your the compressor if it's max output is even remotely close to the required flow needed by the machine. Maybe even a last chance desiccant just before the machine?

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