I would like to build a vac system with a "gast" type pump al la Joe Woodworker and using Brady's coroplast I think it would be a way cheaper alternative to the Ibagna-NA system. What I'm curious is about the multitude of variants, rotary vane, single/ dual stage, piston, oil less, .25 to 12 hp etc ect etc. I'll be cutting very hard plastics and thick aluminum so when I won't be vice holding material I'd like to be able to use vac pucks. Could somebody break down the various types of small vacuum pump for me. TIA Neville.