Ok, so I'm cheap!

It saw a buell wind screen made blue plexi, and thought I could do it. I had a piece of clear sitting around so I drow out some lines and started heating it with a heat gun everything was going good.
I used a mufller, small can, and pair of looking pliers for weight to get the shape I needed. I thought I might ned to cut some stress reliff lines and that was my biggest mistake. at first it worked fine but I put a little to much pressure on it and the damn thin splitt right down the middle. 

So I think I can do a better job with a little practice. I found 5 sheets of transparnet blue for like 40 bucks so I'll try again. 

Make templates out of cardboard before cutting the plexi. I think lexan may be easier to work but I'm not so sure. Use lots of heat and work really slow, I wouldn't cut any relifs as these turn out to be stress risers and can cause it to break (as you found out). Also, to avoid the stress risers, try bonding the plexi as much as possible rather than drilling holes and bolting it. The holes usually cause cracks down the road.

If you do drill holes, debur them. also smooth your cut edges as much ad possible with fine sand paper. A rough edge is asking for a crack.

You may try soaking the plexi in hot water rather than using a heat gun. It may be worth a shot

Try searching out home homebuilt airplane sites. Some planes require you to build your own canopy, and I'm sure those guys would have some advice.

Let me know how it turns out. I've been thinking about this for my CBR1000 streetfighter project.

The brackets are the hard part.

Here's how I do it:

1) Buy some 1/4" plexi at home depot.
2) Cut a cardboard template and ductape it to  your bike for fitment ideas.
3) Dremel the plexi (yes it works) it according to the cardboard template.
4) Use a razor sharp knife (dragging it along the edge) to smooth the edges.
5) Sand the edges with 220 grit.
repeat 5
repeat 5 again.
6) Heat your girlfriends' oven to 325 (ever noticed everything is baked at 325 ?)
7) Put a CLEAN towel on a cookie sheet and drop on your plexi.
Pop it in the oven for 20-25 minutes. (no, it shouldn't smell at all)
9) Test it with oven mits, if it flexes easy, time to form it.
10) Drop the screen carefully into a 14" or bigger diameter trash can/whatever and press gently to form it to the radius.

waiiiiiit


Once it cools you can drill glue it up to your brackets (the hard part) and try it out.

Takes about 2 hours to do. The brackets are what takes the longest, followed closely by the actual cutting of the plexi with a Dremel.

Have fun !

I was just thinking of turning my National Cycle N2590 Deflector screen upside-down, and adding some door trim to the top/now bottom.