PakMaster 50 air requirement question.

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I just got a second hand Thermal Dynamics Pak Master 50 (35 amp max) plasma cutter with an upgraded SL100 cutting torch.  The manual says 200 scfh for cutting 230 scfh for gouging at 70psi (i'm assuming that translates to 3.34 scfm and 2.8 scfm) so i went shopping for an air compressor.i got one that does (according to its manual) 4.9 scfm from Harbor Freight.  I know thats not a lot of "headroom" but i took a chance.  I ran the air line into a two stage filter that has a weep hole which will let out 10 scfh (0.17scfm) to push out water/oil.  On paper, that compressor should be enough, but not so.  I was testing it out on some 16 gauge, and it would only cut up to 4 inches before it quit due to not enough air.  The Tank pressure says 125psi, regulator is at 100, yet the plasma cutter's dial shows only 40psi even though the regulator on the plasma is wide open.How big of a compressor do I need for this cutter?  I will only cut up to 1/8", with occasional 1/4" even though this cutter is rated for up to 1/2".60-80gal, 2-7hp, 110/220.... at say 12scfm @90 psi?  I did get the rubber hose and ditched my old pvc ones.Last edited by oxy moron; 09-16-2009 at 03:37 AM.
Reply:Hello oxy moron, this may sound a bit simplistic but have you tried to bypass or remove the regulator on the cutter and just run the one on your compressor? It sounds like there is a possibility of the system being plugged or having a faulty built-in regulator in it's current condition. There is a good possibility that your compressor isn't the issue and an internal problem with the air regulation system on the plasma cutter might be the culprit. Just a bit of food for thought. Best regards, Allanaevald
Reply:It sounds like a flow restriction downstream of the compressor. For that flow rate you really should have 3/8" id hose....not 1/4" or smaller.....also, check all of your plimbing fittings for a restriction....and check the plasma's internal filter....it may be plugged. Even a small piece of teflon tape or a chip off some brass plumbing threads can be the culprit....but the fact that you have 100 psi at the compressor and 40 at the plasma says that there is a serious pressure drop....and the plasma needs at least 60 to 65 psi to satisfy its internal pressure switch.Jim
Reply:Originally Posted by aevaldHello oxy moron, this may sound a bit simplistic but have you tried to bypass or remove the regulator on the cutter and just run the one on your compressor?