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NoCoast
Rivets suck. At least I personally hate seeing the broken lexan where the rivet cracked it. I also really hate drilling out rivets. Which is why I used stainless button head socket screws and wing nuts. I think I'll switch to stainless rivnuts or similar next time though.

I agree. There's no way we'd ever egress through the rear windshield anyway...neither of us could fit through the X to get back.

But I don't want this thing flexing/bowing in at the middle, so it will probably be 3/16" (which will also help avoiding cracking the lexan where its bolted in).

The tint is a great idea as well...should be fairly in expensive, especially if I just walk in with it before its mounted.

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A1337STI
That's a Brilliant Idea

1) increase thickness
2) tint is nice in the south west
3) put the tint on the outside, once it gets scratched just replace the tint , not the lexan.

You can buy tinted lexan too. Saves the hassle and expense of applying tint, and I'd be willing to bet that the extra expansion/contraction the lexan sees with temperature swings would ruin tint in short order (bubbles anyone?).

Tint on the outside won't last...or at least will scratch even easier than lexan will. Racing in the dirt + static cling + clean your windows during service = scratches all over the tint.

There is motorsports grade lexan but it's 3-5x the cost I think, so my thought is that you're better off just planning to replace it every so often. Besides, if you're using it for a rear window or rear side windows, who really needs to see out of those.

Dave

Don't think about it as a weight savings thing.

I went through all this. figured i'd remove all the glass and save weight. Then a friend of mine actually had his rear window out of the car, and had weighed it the day before..11lbs for a GC rear window. Lexan is almost exactly 1/2 the weight.

Make it from 3/16 and don't worry as much, or 1/8 and install a couple of aluminum "stays" in the middle of it (nascar style).

And i defy someone to actually protest you for having 1/16" smaller than factory glass. FWIW, in my GC front door windows are 5mm, rear doors are 4mm, I did not measure the rear window.


and from experience, buy the tinted Lexan, and don't tint the clear. The tint on the lexan will look like shit in approx 4 minutes.

laneautomotive.com I punched in windshield for circle track. Its listed as scratch proof or standard. I drill the hole bigger then what the fastener calls for. In 10 years of racing Ive never seen lexan crack. Plexi glass cracks easy.

Theres a trick with using 2" tape and 3/4" tape to transfer the opening to the lexan for a perfect fit. Its hard for me to explain but I will try. You line the opening where you want your outer edge of lexan with the inside edge of 2" tape. You rough cut your lexan aprox 1" big and lay over the tape. You then take another strip of 2" tape and line up the outer edge of the first strip of tape and stick it on top of the lexan. You then take your 3/4"tape and line it up beside the second piece of tape all ready on the lexan stick it down then peel off the 2" tape and theres your final cut line.

A jig saw rough cuts good. I would rough cut it big by 1/8" or so. then I use a flapper sanding disc on a 4" grinder (be careful it can run away easy) and a file for the final fit.

I ended up using 3/16 lexan for an XR rear hatch (trying to follow the rule book to match thickness). It was thick enough to avoid any flexing. It is sealed with silicon and attached using stainless button head screws in the center and on each side of the corners. As mentioned I would paint the edge in black to cover the attachement area to give you a clean finish. I have no leaks with the silicon (haven't needed to remove it yet). The screws pulled it to the curve of the hatch and kept it in place. Its been in the car for several years now and the car is always dusty from driving local backroads and it still looks unscratched (and I throw motorcycle jackets and gloves on it almost daily when I get home). My side windows look much worse and need replacing.

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Reamer
Theres a trick with using 2" tape and 3/4" tape to transfer the opening to the lexan for a perfect fit. Its hard for me to explain but I will try. You line the opening where you want your outer edge of lexan with the inside edge of 2" tape. You rough cut your lexan aprox 1" big and lay over the tape. You then take another strip of 2" tape and line up the outer edge of the first strip of tape and stick it on top of the lexan. You then take your 3/4"tape and line it up beside the second piece of tape all ready on the lexan stick it down then peel off the 2" tape and theres your final cut line.

A jig saw rough cuts good. I would rough cut it big by 1/8" or so. then I use a flapper sanding disc on a 4" grinder (be careful it can run away easy) and a file for the final fit.

That is way too much work for me!!!

I laid the old glass on the lexan, drew a line, cut with jigsaw, voila.
The side windows were more interesting since we had no template. If I recall, we rough cut to approximate shape but bigger, held it over the hole, traced it, moved out 1-2 inches, cut it, held it up, marked any trimming spots, then used that piece as a template and a future spare.

It is actually way less work then you think. As long as it took you to guess on your trace you could of had an exact fit. The tape trick also works good for fitting fiberglass hoods hood scoops and rust repair panels.

Ford got DQ'd from a WRC event for "too thin" rear lexan. So it happens if people are looking for it.

That's also the WRC level, where tech people are paid to tear cars down after events, and or competing manufacturers will gladly put up $$$$ in protest fees to gain manufacturer points.


IMHO, the rule is a little bit weird. Different cars run with different thickness of glass from the factory. I remember building a car a couple years ago, and we followed the rule, but the OEM windows were actually less than 1/8" thick. Windows were similarly sized to other cars which have 3/16". There really should just be a minimum spec for Lexan, that we know is thick enough. Certainly for a rear windshield where a it's main purpose is to keep dust out, and rain off your head, 1/8th is certainly good enough. And "industry standard" in drag, roundy rounds, road racing, etc is pretty much widely received as 1/8th.

So what if enough people ask RA to change the rule for lexan to have a minimum of 1/8"? Think they would budge?

They seem to make changes every year and there year is all ready over so its probably a good time to start asking for changes.

If enough people ask NASA, since its a club, they will definitely change the rule.

If enough people ask RA, since its a private corporation who knows, but since we are their customers I'm sure they will consider it.

I'm down to ask for a 1/8" standard!

I have been looking in to molding polycarbonate windows but I would at least
skin them with a clear film to protect them from scratches and don't use rivets
the pressure around the rivet will start cracking even polycarbonate over time.
There is a glue that bonds to polycarbonate permanently etching in to the material
but would it bond to the existing glue.

I will try and set up my heat bank and make an oven and try and mold some
polycarbonate I have been planning for a long time to sell nice molded windows.

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Reamer
So what if enough people ask RA to change the rule for lexan to have a minimum of 1/8"? Think they would budge?

They seem to make changes every year and there year is all ready over so its probably a good time to start asking for changes.

Get the right letterhead for a Talent Management Agency, preferably the some agency they already use, claim to be a rally "God" or a rally "Superstar" throw in all sorts of buzz words about "leveraging" and use the phrase "to grow" by writing the abomination of the pooor long suffering English language 'grow' like 'allow 1/8" lexan to grow the leveraging of symbiotic ......" (study the comic strip "Dilbert" for all the buzz words you need---obviously they do) then include some 8x10 glossies (don't forget you team flat brim baseball hats and if you don't have a soul patch draw one in with a sharie----on your chin Einstein, not the photo---we're creating "reality marketing" dammit.)

and I'm sure that everything will be alright.


John "the man with All the Answers" V*







* all the answers are guaranteed correct.
Some may not exactly correct for your question however...

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
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is 3 hours behind Eastern Standard Time.

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A1337STI
If enough people ask NASA, since its a club, they will definitely change the rule.

I'm down to ask for a 1/8" standard!

Do a search on here... I've already talked about just making it 1/8".

It's in my "list of 2012 things".



Anders

---

Grassroots rally. It's what I think about.

You can use 1/8" lexan A-OK if you support it with some 2-3 rods front to rear in the opening. Spring steel rods work great about .150" in diameter. I used to pull vinyl roof headliner bows from 60's or 70's car to get this type of rod. Regular steel or AL rod might work if you can attach it to the opening's frame and keep it taut.

Mark B.