I believe there is an article in the recent Soaring magazine about
building one. But Wal-mart ( good 'ole walmart) or Home depot sells
fully portable units that hold a half dozen gal. or so at 100 plus
pressure at a very resonable price. Hope that helps.
Craig

wrote:
Does anyone have any experience or can make a recommendation for a
portable air pump ? This would be to add some air to a main tire
without having to go back to the shack for a "real" heavy-duty
compressor.

Cheers, Charles