im wanting to look at a used model 29.5 PSC 80 gallon 7.5 hp 26.2 cfm @90 psi continuous.
magnetic starter, 40 amp

seems like a decent CFM, what should i look for?

For a one man shop you need at least 15 CFM and 80 gallons IMHO. More is better since the compressor is the heart of your shop.
Can't speak to the Northstar brand but suggest you check for reviews on them.

thanks coronet, there was no way to test this compressor from the person selling it so i skipped.

I'm looking at a new maxair that is made by wood which does eagles also, it's a 3 cylinder single stage 60 gallon 18.5 cfm it seems perfect for me, which is for the devilbis finishline 4 which requires 13.5 at 23psi and occasional d/a sanding and a cutoff wheel. all the reviews i've seen were good, just a lot of coin to spend and want to be sure.

I put in this commercial Campbell-Hausfeld 80-gal a couple of years ago; been very happy with it. For $2K you get 25 CFM.

http://www.homedepot.com/p/Campbell-Hau ... /202959361

I don't know much about those 'northern tool' house brand compressors. They *must* be made by someone, I doubt northern tool is fabbing them. My bet is they are coming off an ITW assembly line, somewhere.

One thing I also look at when comparing air compressors is weight. If two compressors have the same exact specs but one weighs 100 pounds more than the other, I'm going with the heavier compressor. Might sound silly but you have to wonder why the weight difference.