Pipe clamps work best on glue-ups that are wide but not very deep. So, what do you do when you need a clamp with longer reach?
shop tip 3

Thread together 34 " black-pipe fittings to fabricate a set of sliding extension jaws for a 12 " pipe clamp. Pick a nipple length that fits the situation, then thread a tee fitting on one end, and a 90° elbow on the other. Make two such jaws. Remove the sliding jaw of the pipe clamp, and slip the tee fittings over the pipe with the open ends of the elbows facing inward. Replace the sliding jaw, and clamp your project, protecting the wood from the rough iron of the elbows.
—E.E. Reynolds, North Charleston, S.C.