re: Shop Air Filter

Thanks for all of the info Nathan.  I'm going to do some work in the shop today even though it's 90+ so I'll get a chance to see if it looks like it I'd doing anything.  I'm a bit concerned that the flow drops off a lot with the small amount of pressure drop across the filters.  

I'm also going to do some planing which will give me a  chance to find out if my red neck grounding works or not.