I like the the ideas about filling the tubing but there seems to be different thoughts about isolating the shelves from the threaded rod. Rigid is very important but most of the better rack manufacturers use some sort of isolation between the shelf and the frame.
I am planning to drill and tap the bottom of the rods and screw in heavy brass spiked feet.
I am planning to drill and tap the bottom of the rods and screw in heavy brass spiked feet.