Re: Onboard Air question
JC Whitney has the switches available...I got one for $13, shipped to my house. As far as the re-cycled oil question...The only problem relates to the purpose of the filter...to filter things. What you will do is filter out all the oil, water, and dust/dirt in the air, and then put that into your oiler, where it will be continually run through your compressor. All the moisture the filter removes will end up in your compressor oil. To address that problem, I'd add a pre-filter of some sort before the oiler that will remove dirt/dust/moisture...and let it drain out on the ground...then add your oiler...then the compressor...then the overload valve...then the second filter (plumbed to return oil to the oiler)...then the pressure switch. If you want the second filter/oiler to work together automatically, you'll have to leave the little valve on the filter cracked a tiny bit, so a bit of air escapes, blowing out oil/etc. with it. The air will then blow the oil back to the oiler. You'll probably have to experiment with oil levels a bit, but it should work.
Moneyless, Will weld for jeep accessories.