Compressor CFM ratings???

by griffin ordway
(carlsbad, ca.)

I need a compressor to run my blast cabinet. Blast cabinet specs indicate that it uses about 45 cfm, but doesn't indicate the psi for that number. The operating instructions for blasting metal parts suggest using pressure between 80-100 psi, and between 30-40 psi for plastic parts. I am looking at two stage compressors around the 7.5 to 10 horsepower range, with 80 to 120 gallon tanks, and ALL of them only show the cfm rating at max pressure of 175 psi. How on earth does one figure out what the cfm is at say 90 psi? I am really confused in general about how to choose the correct compressor, when none of the manufacturers publish any kind of a "sliding table" or graph relating to cfm at particular pressures.

Another article I read said to the cfm number shown by the manufacturers is ONLY for filling the tank, and not for delivery to the tool??????? Please help....I am trying to set up my shop and get my business up and running, but this dilemma has me flummoxed.
Thanks, Griff

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Feb 03, 2016
CFM with a grain of salt...
by: Doug in s.d.ca

"Another article I read said to the cfm number shown by the manufacturers is ONLY for filling the tank, and not for delivery to the tool??????? Please help....I am trying to set up my shop and get my business up and running, but this dilemma has me flummoxed."

If you can, I'd like to have a reference to that article. Could be flat wrong, or possibly for a particular application.

Depending on how long and often the blaster will be in use, you may be able to use a smaller compressor (or two) and a bigger receiver.

Details...

Feb 03, 2016
Compressor CFM ratings
by: Bill

Delighted to help, Griffin.

All the information you've asked for is already here on the pages of this site for your use.

Please help yourself.

Note that I've moved your question to a more appropriate forum, and suggest you read the pages on pressure loss for a better understanding of the flow issues.

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