Plasma cutter air requisits

[Dodge]

Ellen,
Thanks for clarifiying the scfm / cfm difference. If I understand it correctly then scfm would denote perfect texbook conditions and cfm would denote actual average shop conditions? I know thats probably grossly over simplified

[Ellen]

Dodge, I think you've got it!

[Ten Hammers]

OK I guess my ignorance shows. Can you tell me the reason for posting 2 different cfm ratings ( at different pressures ) ?
Northern Industrial Electric Twin-Stack Air Compressor — 4.3 Gallon, 2 HP | Electric Powered Air Compressors | Northern Tool + Equipment

[Ellen]

Ten Hammers, long time since I studied physics but as I recall, Boyle's Law(s) which cover the behavior of gasses show that volume is inversely related to pressure; i.e. pressure goes up, volume goes down. A practical example of this is a coal forge blower which moves a larger volume of air at a low pressure and works well, vs. trying to manage a coal fire with an air compressor which produces a higher pressure and a lower volume. Sorry if my explanation is not clear, perhaps others can be more lucid on the topic.

[Dodge]

Steve,
Another oversimplified explanation, (kiss) might be that they are advertising the high and low end of typical useage. 40 psi being the minimum that most paint sprayers woul require and 90 psi being the highest working pressure that OSHA will allow in the workplace. Just a guess, uneducated at that

[frogvalley]

Dodge-

What plasma cutter are you considering? That would help with the advice.

I have a Thermal dynamics CutMaster 38. Its their small unit and will cut up to 1/2or so but works great on 1/4 and 1/8 which are more common sizes to work here in my shop. It runs great off of our painting compressor which is a three horse with a twenty gallon tank. We rarely have to wait for recovery but sometimes do. Not a big problem though.

To answer your question more directly, the compressor will make you wait if its too small, we first tested this unit on a smaller one horse and it worked for a minute at a time and then we had to wait. The tank size is important but secondary in my opinion, the recovery time relating to the actual output of the compressor is more important.

[Dodge]

I bought the Hypertherm powermax 380.