We built a single segment of the rack, for test purposes, using available materials. It is not as floppy as the real thing will be, but it should be adequte for testing manipulator arm ideas. It is ten feet tall, so we can mount a light at the top as needed.
BOM: 20 feet 2x2x16ga square mild steel tubing, 3 square feet 18 gage steel sheet, 1 foot 1/2" steel sch40 pipe, and half a dozen or so iron weights.
Equipment required for build: MIG welder, chop saw, tin snips, grinder.