OK, Keilau, let me clarify because you're absolutely right, that filter does come with a 3/8 male to 1/4 female adaptor (x2). I probably should have mentioned that when I bought the compressor I also bought a little accesory kit (I think about ten bucks, no more than $20) that came with a 1/4 NPT male to male, the quick disconnect, several male QD fittings, as well as some other stuff, like a blow gun and a nozzle for filling tires and what not. With that kit I didn't need to buy anything else. Well, except for some teflon tape.
Now, you say that filter is high flow so it could be better. Tell me more. Should I be using a low flow filter? maybe I could add another filter (with a finer grid but without the water trap) down stream from the water trap? I haven't had any problems so far but I don't want to start having trouble right in the middle of a paint job. I'm also wondering about the wisdom of using the same filter for both compressors. I attach the filter directly to the compressor on both of them, so I don't see what the damage could be, but perhaps you know more than I so please share your experience. I know that without the filter on the larger compressor my DA will start bleeding water after a while. The larger compressor is the Sears Powermate 26 gallon 1.6 HP model. Yes, I know, I really shouldn't be using a DA with that but the flow rate of the compressor is 5 cfm at 90 psi and that's exactly what the DA says it needs. But for this discussion I'm mainly concerned with the little airbrush compressor so any tips or advice on how to make that set up better and/or trouble free will be most appreciated.