Here's a slick snap-in, snap-out storage rack made from PVC pipe. For 1/2-in.-diameter iron pipe, use 3/4-in. PVC, and for 3/4-in.-diameter pipe use1-in. PVC. To make the rack, cut 2-in. lengths of PVC, and with a hacksaw or band saw, slice them lengthwise about 3/16 in. past the diameter's center line. This creates the gripping action to firmly hold the heavy iron pipe.
Drill and countersink two holes in each PVC piece, then space and screw them along a pair of 2-in.-wide boards. Attach the upper board to your shop wall and snap a pipe clamp in either end to position the lower board for screwing to the wall. That's it. You've shaped AWOL pipe clamps into an orderly arsenal.
Cut two 12 x 16-in. pieces of 3/4-in. plywood and temporarily screw or nail them face to face. Drill 1-1/4-in. holes (if your pipes are 1 in. outside diameter), spaced 3 in. apart, through both pieces. Pry the plywood apart, then screw them to two 16-in.-long pieces of 2x8 to make an open-ended box. Add a couple of narrow 3/4-in. boards on the bottom for feet, then set the box in a convenient spot along a shop wall. To keep it from sliding, attach it to the studs with screws driven through the 2x8s.
Build this rack from scrap pieces of 2x4 and a 3/4-in.-thick backer board of whatever length you need. Cut 6-in. lengths of 2x4, with 45- degree corners on the bottom ends so it's easier to slide the clamps into the rack. Measure the O.D. (outside diameter) of your pipes, then add 1/8 in. for clearance between blocks. Space and screw the 2x4s along the backer board, creating gaps 1/8 in. wider than the pipe's outside diameter. Finally, screw the backer board to the wall and load it up!