Thanks.  So simple (and probably obvious) but I do tend to "over-think"

Well the perfect thing for weighting stuff down is stage weights but they can be hard to get a hold of.   For those that do know know what I am talking about, in theaters there is what is called a fly system.  It moves the backdrops up and down. It is a system of pulleys and ropes to state it simply that are weighted with stage weights. They are about the size of a brick only longer and very heavy. Same kind of weights can be found on exercise equipment.

I bet my husbands old workout system would have been great had we not disposed of it.  Always remembering "one man's junk....".  I did make the prop rack with 3 heights, layered 4, then 3, then ended with 2.  It worked great and I didn't need to weigh it down.  Thanks to all!!!

Well the perfect thing for weighting stuff down is stage weights but they can be hard to get a hold of.   For those that do know know what I am talking about, in theaters there is what is called a fly system.  It moves the backdrops up and down. It is a system of pulleys and ropes to state it simply that are weighted with stage weights. They are about the size of a brick only longer and very heavy. Same kind of weights can be found on exercise equipment.

Sand bags can easily be bought or rented from your local theatrical supply company - lighting companies often have them. Of course, you can also go to your local craft store, buy some toy plastic pellets, make a 'pillow' and fill it up. That's what I did to make weights for shadow puppet screens.