A shop vac is not the way to go. Shop vacs pull filtred air accross the motor
to cool it and the motor's bearings. Add a bit of grit to that airflow and you
will have a destroyed motor in short order. Regardless of what the vacs
manufacturer offers as their best filter element, it will not be fine enough to
filter the dust out. After destroying several shop vacs, I replaced the motor
with what is called a "by-pass" blower. With this type of blower, the airflow
does not pass the motor, so the grit does not damage anything. I used to by my
motors from Grainger.com.