I have to dis agree IMC water based does not require more psi Fact . Higher psi was used years ago to smash the particles onto the surface but since everyone switched over to lvlp and hvlp in the body shops the max psi at the gun tips is no higher than 10 psi regardless of the input psi .I spray cars etc and i never use more than 7 psi at the tip these days if i am using the turbine set up .If using a compressor i never use more than 28 to 30 psi at the gun gauge which gives no more than 10 psi at the tip .this is with automotive water based paint .When using my aztek AB i have been down at 5 psi to get the desired effect and i never use more than 30 psi even when using specific AB paints .I am using trident at the moment which is superb in flow etc and virtually no tip dry either and use this at very low psi .The viscosity is what really dictates required psi .