I guarantee these dimensions and angles for the same amount you paid for them. :) Seriously though, I'm sure the above measurements are not perfect, but they're darn close.
I spent Monday evening ripping and sawing a 4'x8' particle board into the various pieces I would need to make the forms:
The support rail form is easy - there are only two pieces, each 3" wide, so I made a single form about 10" long. I'll make a single laminate off of that then cut two pieces out of it. I admit that I pestered Ian about this because I was skeptical that only two support rails were needed for the entire wingnet rail. He assured me that the vertical loads on the rail are relatively small and that two supports are sufficient.
The main rail will be roughly 9' long (guesstimating because I don't know how wide the beams will be) so I cut up enough pieces to make a 10' form (in 6' and 4' pieces). Here's a email response I got from Ian on how long the main rail should be:
Just leave them hanging close to the beam, I will come back to this when I have the first set of beams made and make any provision then - they may attach to the beam join flange.
Here's a woodworking tip that I learned: don't try to cut particle board with a finish (fine-tooth) blade. It will cut like crap, and makes a burning stench and even some smoke. (Thanks Bill, for loaning me the right blade -- wow, what a difference that made.) But even with the right blade, cutting particle board sucks because it produces clouds of dust. I was wearing my respirator the entire time.
Tonight after work, I got to work on constructing both forms. The weather helped out a great deal -- we had a 90degF day, I used Fast hardener, so things went really quick. Here is the support rail form, all glued together with the edges rounded over:
I think this was the first time I've ever had to deal with pleats in the bag, and as you can tell it wasn't the neatest job in the world. Eventually I got it air-tight and it's out in the garage right now under 25 lbs of vacuum.
I also got a lot of work done on the main rail form. This form is more complicated than the little one above, of course. I just took it one step at a time, gluing the pieces on with epoxy and waiting for it to get to a reasonable cure before moving on the next piece (lucky the weather was so warm). I was concerned about how I would clamp the angled joins, but the epoxy grabbed the pieces fast enough that just a few minutes of holding them in place by hand was sufficient. Here's a few pictures of the construction.
First join getting glued:
This is the only right angle in the form; I took advantage of this and used clamps: