Where are you getting the compressed air now?
Sand blasting is pretty air intensive...
Another issue you would likely find is that the blower fan is not designed to push air into a pressured environment. Would likely overload the motor fairly quickly and burn it out.
X2 on a compressor. Very useful to have regardless, and like so many other tools, once you have one, you will wonder how you ever survived without.
I have a little Porter Cable pancake that I got at the HD about 6 years ago when I needed something smaller than my Emglo. Still works great, but it's a noisy little bastid. Plan on having enough hose to put the compressor as far away as possible if you are going to be using a lot of air.