Diane-
I have an Aluma Shade I got at Costco @5 years ago, and two others that are steel frames. The AS is significantly lighter in weight than the steel frames.
One of the steel frame Caravans had a couple broken struts, and when I called Caravan for replacements they asked what color they were? I assumed they are all white, but they color code them, one has blue specs and the other brown in the white, not sure if it has to do with models or age of the frames?
But long story short- Canopies by Fred in Ballard hooked me up with replacements, and he stocks all the Caravan models and makes the weight bags we all love here in PNWBALand!
http://www.canopiesbyfred.com/