[enkeivette]

I've done quite a bit of spraying using my friends 10 gallon 1.5hp air compressor and Costco paint gun, and I've gotten surprisingly good results at about 50psi.

So I've been shopping around for a compressor for myself. I was looking at a few 2 hp compressors, which put out about 6cfm at 40psi. I saw a compressor size selection chart, and saw that 10cfm is recommended for HVLP guns. Which is surprising because the one I've been using probably puts out 4cfm and worked fine.

It seems to me that an air tank would flow whatever is asked of it, so are cfm ratings based on what the compressor can supply once the tank starts to drain? Meaning, will a 20 gallon tank rated at 6 cfm actually put out 10cfm or whatever you need? Is it just the compressor that won't be able to keep up? (Putting out only the rated 6cfm)