What thickness polycarbonate do people use to make their windows and how do you cut it?
What thickness polycarbonate do people use to make their windows and how do you cut it?
You use 1/8-1/4", if you're using less than 3/16" on the windshield you should have support braces or it will bow in at speed. You cut it with a circular saw, ideally while pouring water into the cut.
Keep in mind that unprotected lexan will scratch like butter. There are powerboat shops that can put a hard ceramic coat on it (and do other lexan windshield fabrication). Protective films are a cheaper but weaker solution.
Sorry about the edits, checking my notes.
Ask for Margard. Its a scratch resistant coated Lexan(more expensive). Also, thinner is way easier to work with. Also also, if you go that route, you have to kiss your wipers and any kind of careless cleaning goodbye. Sometimes glass it the way to go.
Yeah I'd stick to glass unless you're really desperate for the weight savings or you're making windows for a custom car. Lexan is no fun.
Well it is for my Challenge car and I am aiming for sub-1500. It would be for the rear side and rear windshield.
I use 1/8" normal Lexan on the rear window of the Targa car. It's been about five years now, no complaints at all.
I think it is a good trade, I almost lost an eye in a crash from windshield glass getting blasted in my face. If you are concerned about vision in the rain, Rain-x > wipers X100 If you go with poly carb get the treated/coated stuff, it will help out some with the scratching and will act like Rain-X for a while. I have read that there is a coated Lexan II gold or something like that, that is supposed to have really good scratch resistance. I went with Clear One since Summit racing is close by, but window shops would be a better place to check with. I cut mine with a dremel and router bit and attachment against a clamped on straight edge. Make a template out of taped together poster board or something similar.
The worst part I ran into was the seal. If you can reuse the OE seal try and do that, otherwise look at what some others are doing on theirs. If you do it wrong you can crack the Lexan, or get annoying squeaks or leaks.
Buying a sheet from a wholesaler is cheaper than HD. Piedmont Plastics is a good supplier.
1/8" looks better, 1/16" will be a little warpy, 1/4" is overkill IMHO. Weigh the stock glass though. I've made entire hatches out of lexan for past challenge cars that yielded BIG weight savings, but on the turd we were shocked to find how light the rear glass was, and ended up using it.
Cut 1/8" with a BANDSAW. Someone who knows what they're doing can nail it on the first shot. 1/16" can be cut with a rugged pair of scissors. I've done a couple of our CRXs with 1/16" on the 1/4 glass and sprayed the inside black. It photographs well.
SCCA requires 3mm on side and rear windows, and 6mm on the front windshield. Front and rear also require supports. That's 1/8" and 1/4" for those metric system challenged individuals. Place masking tape where you want to cut and also on the bottom of a jig saw. Cut with the jig saw using a blade with as many teeth per inch as possible. It can be formed using heat, but you have to be careful not to overheat and cause blisters. When I make windshields, I lay the piece over a glass windshield and heat slowly using a huge tipped plumbing torch. Once it get plyable, and starts to sag, I lay another windshield over it and clamp in place till the lexan cools. Takes serious patience. If you have access to a pizza oven, use that as it's much easier.
In reply to tr8todd:
SCCA requires that for road racing or for autocrossing?
In reply to 93EXCivic:
These are the SCCA Solo rules for prepared class. I don't think there's a general safety rule about this for solo, but clearly this would be within it if there were:
K. Windows
Oh, FYI that's from the 2011 rulebook. I'm almost positive it hasn't changed though.
When I do Miata hardtop windows, I don't form the Lexan. It's flexible enough that it conforms easily, even to the sharp angle on the side. I've also done a windshield out of 1/4" and again, no forming. I usually rivet them in.
What about cutting with a jig saw, for those of us that don't have access to bandsaw? Anyone tried it?
So, for my Europa with a broken windshield and replacements at $550(shipped, not installed), would one of the coated lexan varieties be a decent choice for a street-driven autox toy?
Any ballpark idea of the cost for coated lexan?
I paid about $250 ish for a Harwood 1/8" Margard windshield for my Camaro. I don't think Lexan is legal for a windshield on a street car (no DOT markings) and don't use wipers on one either, it will scratch the first time you use the wipers. Not a good choice for street use. You can get 4x8 sheets for a little cheaper, should be able to get it locally.
I use a jig saw to cut. Or an air-powered reciprocating one, which is pretty much the same thing.
The non-coated Lexan I use for Miata rear windows runs about $60. Look in your local yellow pages under Plastics.
how are ppeople attaching it in replace to a standard back window? Like a window, or screwing it/ribbiting around the frame?
I've always riveted, although I might see if I can use the factory window fastenings next time.
http://targamiata.com/tags.php?tag=lexan%20window
is riveteing the same as ribbiting? 
been a long day..
GrantMLS wrote: is riveteing the same as ribbiting?
it's okay, it's not easy being green.
Your local circle track stock car supply should sell a 42" X 72" shhet of race car polycarb for around $80
Aeromoto wrote: Your local circle track stock car supply should sell a 42" X 72" shhet of race car polycarb for around $80
Is that for used pieces or new? That is a really good price either way.
jere wrote:Aeromoto wrote: Your local circle track stock car supply should sell a 42" X 72" shhet of race car polycarb for around $80Is that for used pieces or new? That is a really good price either way.
New, you have to cut it to fit.
You'll need to log in to post.
