I dont think anyone would have a problem with the thinner lexan window. I had an ex-prodrive shell and the rear windows (factory STI RA from Japan) were SUPER thin - most likely thinner than what you're dealing with in that Lexan. And you can believe all the VSC guys are using that glass. Besides, if anyone protested you over a rear window I think the negative feedback would be so heavy that it'd never happen again...

the 1/8 is going to look like shit on something thats not almost flat unless its formed.
I think some of the bigger budgets already have 1/8.

update....probably going to order tomorrow. They don't actually have the 'treated' stuff in 3/16", so going down to 1/8" (with scratch resistant coating on both sides, so technically thick enough for the rule book).

but its still going to need some support, my local metal shop has stainless steel .188" rods, I was going to get 2 of them and weld them lengthwise to the frame. anything else I should do for support, or is that enough? Cross pieces?

I really dont think you will need any cross pieces. Ive installed and seen many windshields with out any support and they hold up well. You can always add support braces later easily. The Subaru rear window isn't that big and the small curve it does have will help keep the lexan stiff. Thats your call I guess. If you feel you need support for good measure then do it.

If I were to add support I would run 2 top to bottom evenly spaced. Stainless for supports and to fasten sounds like a good Idea.

yeah, good point.....I can always remove the window and add the stiffeners later.




heheheheh....I said 'stiff'.

I use well nuts to fasten Lexan to metal. Works well on bike windshields as well as car stuff. The only issue is that on older cars the flange might not be wide enough. New cars have huge flanges that make it easy. The well nut is covered in rubber that insulates the Lexan from the metal fastener and keeps the Lexan from cracking as it flexes with heat and movement. I also use a thin layer of foam tape under the Lexan both as a waterproof seal and as insulation from the metal flange.

Well Nuts:
http://www.hansonrivet.com/w71.htm
/topkayaker.net

Here's what they look like installed.

Ahh... I hope that isn't actually what they look like installed--if so you could have just used a normal rivet.

We use the rivnuts which are similar to the well nuts--the bolt/screw holds the lexan down, not the rivet part itself.

That was my first thought also. I believe he is using them for the rubber protection to seal the hole.

Quote
Reamer
That was my first thought also. I believe he is using them for the rubber protection to seal the hole.

Yes - the rubber is required. Not really to seal the hole, but to allow the lexan to give as it moves around during temp changes or as the chassis flexes a little. If you bolt it straight down with holes just large enough for the bolts the lexan will crack. The rubber gives it some elbow room.