Anyway, enough disclaimers, lets get down to it!
Step 1: The materials
The first thing to do is cut out our circle from our sheet of ply. I measured out 36" up and down and drew the ring with a pencil on a piece of string tied to a nail at the center. I tried to make as close to perfect as possible but the shape is not really that important because it is on the other side of the camera and won't be seen by anyone other than your models. By having a 36" outer diameter I was able to put 12 sockets on there about 5 1/2" - 6" apart. The ring is 6 inches wide all the way around, giving it an inner diameter of 30". You can go smaller in size if you need to but I wanted a big opening to shoot thru so that I can get wide shots without having to crop out the ring in my images.
I cut thing ring in half so that it will collapse down to half size for easier storage. The sliding bolt locks are not ideal for locking it into to the open position and as of this posting I am still looking for a better solution.
Not pictured below:
-20 feet of 12 gauge wire, 10 black, 10 white. it is pretty cheap, maybe 30 cents a foot.
-12 100 watt bulbs, $5
-bag of electrical connection caps, $3
-box of 1" screws (for sockets)
-box of 5/8" screws (for hinges and bolt locks)