Reply by Scot

Blast gates are the way to go. Ball valves are very expensive (try pricing a 4 or 6” ball valve, even a pvc 4” ball valve is over $40), an aluminum 6” blast gate is $12 and 4” is $8 on ebay, plastic blast gates are even cheaper.

I recommend a cyclone separator, a two stage system works fantastic.

I’ll try to post some pics of my system later today.

-- If the old masters had power tools, they would have used them. So get off your damn High Horse.