Hey guys I have a question about cfm's in regards to sandblasting. I am trying to engrave letters into brickpavers for a memorial walkway. The sandblasters needed for this say they use 9 cfms at 90psi. And my compressor says its capable of putting out 10 cfm's at 90psi. If I wanted to blast at 120 psi would I need a much larger compressor? Do I need to blast that high(125psi) when engraving brick and stone?