I won't bother telling you about my blaster....
But save the plexiglass by using the disposable plastic covers sold by TP Tools...
Also the question was asked what blast to use... and there's no right answer for that because it depends on what you're blasting and what surface you want to be left with. I have everything from Iron oxide - to walnut shells... and change it out depending on what's being worked on.
You don't want to blast some old Corvette aluminum valve covers with iron oxide... that would ruin them... so just saying it all depends.
Also if your vacuum is blowing dust in the air -- you have to be careful to not be inhaling that stuff! Use a mask at least. You can get yourself a bad case of silicosis.