sand blasting psi rating

[Tigger]

I would like to know what psi should you use for sandblasting. A friend is letting me use a Blue Point gravity feed blaster.(its a cheap one), but i want to hit a small rust spot under the package tray on my 69. Thanks.

[Tigger]

anybody?

[AutoRust]

Gravity feed blasters dont need a lot ofair  pressure. I would make sure you have a regulator at the blaster, then adjust it up.
Start around 6-70psi, do a test spot on something other then the car, maybe an old fender or something.
Whats more important then air pressure is the flow of material, if its dumping large amounts of sand, it will waste it and not remove much, also if its not enough sand, it will take forever to clean a spot.