making a contact frame w/aircompressor

Does anyone have plans and info on making a contact frame using a small air compressor?  I have one that gets about 30psi, as it was used for an airbrush.  I guess this would be a vacuum frame in reverse.  I use a mercury light so the frame would have to go under the light.  is this do-able or shuld I just build a vacuum frame/  Along those lines the plans available for a vacuum frame are pretty self explanatory but just what kind of pump do you use?  Going to Ebay shows a real assortment or is there a mail order available?  The largest print I make is a 16x20.  Thanks for ANY and ALL help!