Well, you have a few options if your compressor cannot push enough Cubic Feet per Minute of air to match the sandblaster that you want. You can look at a smaller sandblaster that will require less air, you can look into larger compressors that will supply enough CFM to run the sandblaster or you can adjust your sandblaster or pressure pot.
Let's take the Pressure pot for example: The PT-100SK requires about 23 CFM at 90psi to run adequately. If your compressor only supplies half that CFM, you can request to reduce the nozzle size from the standard 1/8 inch diameter down to a 3/32 inch nozzle and then run the pressure pot at somewhere between 60-80 psi. This will allow the pressure pot to operate at around 11 or 12 CFM.
Altering the operating parameters will affect the efficiency of the blaster, but it will allow it to operate at a lower CFM.
Some of the same modifications can be made with other sandblaster also. Just give us a call if you have any questions.