[Shop-talk] compressor/sandblast guru question

[Bob Spidell]

Probably not. My dad has a large IR 2-stage; probably a 'real' 7HP or greater on I believe (at least) a 60-gal tank (maybe 80). It struggles to keep up with his blast cabinet--the compressor is off for the first 5min or so of blasting, then has to run almost continuously thereafter. 

>From what I know of fluid dynamics--not much--I've always wondered what a large tank offers. Yes, the tank will put out more air before it reaches min pressure and the compressor fires, but then the compressor has to run longer to replace the volume of air lost. 

Seems to me you need the most powerful compressor you can get, regardless of tank size, so the compressor can replenish the tank quickly then get a rest cycle. I think the 'HP' and 'gallons' numbers aren't particularly relevant; what you need to know is what volume of air at what pressure the compressor can put out (maybe that's the second set of numbers you mentioned; it's not clear to me). The tank just 'buffers' the air flow. 

Maybe a guru can enlighten us. 

Bob 


-------------------------------- 
Bob Spidell - San Jose, CA 

----- Original Message -----
From: "John Niolon" <jniolon at att.net> 
To: "shop-talk" <shop-talk at autox.team.net> 
Sent: Friday, April 20, 2012 8:42:33 AM 
Subject: [Shop-talk] compressor/sandblast guru question 

Ibve got a Quincy 310 compressor sitting on a 80 gallon tank... using a 5 hp 
motor. Itbs turning about 800 rpm 

the rating is 3.9 to 9.6 ACFM @ 175psig with a 2-3 hp motor... 

Ibm wondering if it will handle a small (bench top) or small upright sand 
blast cabinet without laboring it to death 

Harbor Freight rates their 40# upright model at 9.5 cfm at 90 psi.. 

A NESCO about the same size says 12 cfm at 80 psi... 

An ATLAS says 15 cfm at 100 psi 

sounds like blast cabinets are rated like lawn mower engine horsepower ratings 
!!!!! 

any ideas if I have enough compressor ?? 

thanks 
John