Instead of bare steel pipe for the crossbars, you might consider using rubber coated pipe. This would be much gentler on your equipment- and look nicer, too! this kind of pipe is usually used as electrical conduit (aluminum pipe) or as natural gas piping (steel piping). I have seen a variety of colors- light blue, orange, red, yellow, gray and black. I would imagine it could be found at indutrial supply or plumbing and piping supply companies.