What pressure do you need to apply it?

The spray pressure is variable based on the final consistency of your application. You generally should have a compressor with at least 90 psi at 5 cfm, but the actual spray pressure may vary anywhere from about 30 psi to 90 psi. We recommend at least 5 cfm to ensure you do not have to stop and start your spray application. We also recommend a pressure shut off valve if your gun does not have it since the trigger alone does not always stop the airflow through the gun.