Hey All! Little pancake compressors are okay for running a brad-nailer, and if you're not running the pants off of 'em, they're okay for framing nailers or a short stint with an air-chisel. No point in trying a die-grinder or air-drill.
In the train-picture I posted, in the upper leftish, you'll see two silver cylinders that are cut off by the upper-edge... this is a regenerative combination dessicant-type dryer with an oil/moisture droplet extracting device. The droplet extractor uses a 'torturous path' method of capturing droplets passing through something called Rashig Rings... held in your hand, they look like a coffee-can full of old piston rings, but they fit together pretty tight. Oil and water droplets stick to the rings, while air passes up through dessicant, and out the top. The grey box between the two towers is a selector valve and control circuit board, which alternates drying between the left- and right-side towers every few minutes. As one tower is absorbing moisture(drying the outgoing air) the other side is 'regenerating'... dry air is directed through the dessicant BACKWARDS, flushing out trapped moisture, and preparing it for it's next round of drying.
Just downstream of this dryer is a filter... barely seen in the photo as a white column right next to a white frame leg on the far left side. This filter has a fine screen and paper element, as well as a sediment-bowl type trap at the bottom. It captures any stray dessicant, as well as precipitants from the cooling compressed air. This particular compressor's outlet rating, in addition the the CFM and pressures I indicated in earlier post, are 35% relative humidity in ambient conditions of 100% RH from 35F to 110F, all in 100% duty cycle.
For painting, you'll want a centrifuge-helix-type separator to extract moisture and stray compressor oil... as well as a conventional filter stage or two to keep any crud from finding it's way into your spray-gun. In most smaller cases, a Speedaire diaghram-type compressor might be a better choice... but they ain't up-to-task of running air-tools.