Here are some photos. I’ll explain below.
The orange thing is called a ratcheting strap. It’s a strap that has a ratched thing that tightens it up. The ends of the strap have hooks. It basically replaces rope, and lets you tighten it.
The brown product is epoxy. I had some of this left over. I’m sure any epoxy will do, but this was a plastic to plastic epoxy. It has some fillers.
The chair broke when one of the legs got detached from the curvy support that holds it steady. To fix it, I used the strap to hold everything together, as close to the original positions as possible.
Then, I used an old plastic bag to make a “thick rope” and wrapped it below the leg break, and taped that into place. This will prevent the epoxy from dribbling down past the break.
While tapping the parts with a mallet, to get things into position, I cracked some wood at the back, breaking that corner. So I taped that up as well.
Then, I mixed the epoxy, and dribbled it into the spots where the screws got loose, or the screw holes broke.
The epoxy was thick, and didn’t run down much past the crack. I waited an hour, and then it was hardened and just a little sticky.
I loosened the strap, and removed it. I let the glue cure a bit longer, before putting the chair back into service.
Update: It’s still working on Oct 10.