There’s a lot of DIY solutions out there for big diffusers, and such. Most of them with either wooden or PVC pipe frame. While PVC pipe is certainly lighter than wood, it’s rather flexible, and are still kinda bulky if you need several of them. In the studio, this isn’t usually a problem. But, if you need to get them out on location, you often need them to be as light as possible and take up little room.
Over at Cheesycam, though, they’ve come up with a great lightweight solution to the problem using screen door & window panels. The system uses aluminium struts, with plastic brackets on the corners. For a quick lightweight solution that packs up small, it’s a great option.