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NBS2005
NBS2005 Dork
10/14/09 10:55 p.m.

Anyone make one of these? My RX-7 (I love saying that!) has cracked front glass so I thought about trying to fab something up that is $2010 budget friendly (yes, I've got $510 to play with, see you next year!). Has anyone made one? I was thinking of making it with 2 sheets with a frame of some sort that would help keep it from buckling. Sorta like this:

http://www.theautoist.com/grmwindow06.JPG

Though I realize that is one piece.

Any thoughts?

Keith
Keith SuperDork
10/14/09 11:18 p.m.

Oooo oooo oooh! I've done it. It's easy.

  • make template out of paper
  • trace template on Lexan
  • cut lexan
  • drill holes
  • rivet

It couldn't be easier. There's enough flex in the Lexan to conform to the bends in a Miata windshield without any sort of heat or forming. We used 1/4" in the front and it doesn't buckle at all, even at 140 mph. If you go lighter, such as 1/8" (as I've used for rear windows), you'll want something to support it.

Lexan window

The hard part is going to be keeping the price down to a Challenge-friendly level. Don't be tempted by acrylic (plexiglas), stick with polycarbonate.

RossD
RossD HalfDork
10/15/09 7:16 a.m.

I've heard the trick to make it look professional, like Keiths, is to remember to paint the inside perimeter black.

mad_machine
mad_machine SuperDork
10/15/09 8:48 a.m.

honestly, I probably would have thought of the perimeter thing.. AFTER I installed it

Kendall_Jones
Kendall_Jones Reader
10/15/09 8:54 a.m.

Before the COT thing, there used to be a vendor of used Nascar lexan windscreens (also sold wrinkled fenders / hoods / etc). Sold them for like $20. I still have a couple for my road race projects.

Kendall

Wally
Wally SuperDork
10/15/09 9:03 a.m.

The only thing I would add to Keith's instructions is pick up a roll of self adhesive foam insulation from Home Depot and put down a layer on the windshild flange to cushion the windshield to keep it from squeeking and cracking. Once the windshield is mounted you can run a bead of cheap black silicone around the gap between the windshield and the body and smooth it out with a wet finger to make a neater looking seal.

.

NBS2005
NBS2005 Dork
10/15/09 9:11 a.m.

Keith,

That does look pretty easy! I love easy. Can some kind RX owner go out and measure their windshield for me? I'll wait.............(my car is not here yet, going to be a few weeks before I can go get her).

I found this place on line:

http://www.professionalplastics.com/POLYCARBONATESHEET

Kieth's 24x 60 sheet would be $100 for 0.220 in thickness, $66 for 0.125 in. Cheaper than a windshield.

Next up, bushings and what to do about the interior.

GameboyRMH
GameboyRMH SuperDork
10/15/09 9:41 a.m.

I've been thinking of doing some of mine to lose weight, and for safety (the rear quarters on the AE92 only have a slight curve, and all the glass on the Samurai is FLAT).

How are these things with fog? Better or worse than glass? And what do you do to deal with the scratches, just clear plastic film?

Keith
Keith SuperDork
10/15/09 9:46 a.m.

There's probably a plastic dealer in your town, might be cheaper than shipping. I seem to recall my 0.125" sheet was right around $60 at a local shop.

I've never had any of my Lexan windows squeak. If you use the right size holes for your rivets, they can't move.

I don't live in a fog-prone area so I can't comment on that one. You do have to take care of them though. I haven't scratched one badly yet, but I would not recommend windshield wipers on one.

cxhb
cxhb Reader
10/15/09 10:58 a.m.
Wally wrote: The only thing I would add to Keith's instructions is pick up a roll of self adhesive foam insulation from Home Depot and put down a layer on the windshild flange to cushion the windshield to keep it from squeeking and cracking. Once the windshield is mounted you can run a bead of cheap black silicone around the gap between the windshield and the body and smooth it out with a wet finger to make a neater looking seal. .

or even better, buy a roll of 3M Window weld. its much tackier and is oem for some manufacturers. plus its black.

amg_rx7
amg_rx7 Reader
10/15/09 11:08 a.m.

Can't you just get one from a junk yard, ebay or off a parts car?

John Brown
John Brown SuperDork
10/15/09 11:11 a.m.
amg_rx7 wrote: Can't you just get one from a junk yard, ebay or off a parts car?

Where is the fun in that?

poopshovel
poopshovel SuperDork
10/15/09 1:02 p.m.

1/8" is fine. 1/16" is too flimsy. BEST way to cut is on a band-saw...actually, best way to do it is have your brother who builds furniture and knows WTF he's doing cut it on a band-saw.

Rivets in the channel are perfect, and definitely spray an inch or two around the perimeter black. Bonus points for curved corners. On the civic, I had a strip of 3/4" wide, 1/8" thick aluminum stock running vertically in the center that helped to keep it from wobbling. That E36 M3 gets LOUD otherwise. And yeah, the foam tape is a great idea.

NBS2005
NBS2005 Dork
10/15/09 2:28 p.m.

I've never priced used windshields before. What do they run?

I like the durability factor and lower weight of the lexan.

Does Rain X work on plastic?

poopshovel
poopshovel SuperDork
10/15/09 2:53 p.m.
Does Rain X work on plastic?

Yes. You can also buy polish/scratch remover from lexan suppliers like piedmont plastics. DO be super careful using anything else on there, though. We made an entire hatch out of lexan for our $2004 challenger. The morning we were supposed to leave, I noticed a tiny bit of somethingeruther right in the middle of the thing. I grabbed a can of goof-off and applied it liberally. I was up till 3 in the morning building a replacement hatch.

RossD
RossD HalfDork
10/15/09 3:03 p.m.

When I replaced my cherokee's windshield, I called around to the local shops and then called a national chain. The national chain was only like 50cents cheaper and so I was going to go with a local shop and I told that to the lady on the phone. She instantly dropped the price by $50. I think I paid just over $200 and the guy came to my house after I was done working and we talked cars the whole time while he swapped out the windshields.

daytonaer
daytonaer Reader
10/15/09 3:03 p.m.
NBS2005 wrote: Does Rain X work on plastic?

RainX anti-fog will melt some plastics. Be careful.

Karl La Follette
Karl La Follette Reader
10/15/09 3:47 p.m.

Use a vinyl banner for top of windshield and tearoff www.racetearoffs.com

patgizz
patgizz Dork
10/15/09 4:31 p.m.

the home depot has real lexan now - not sheets large enough for the typical car windshield, but for my truck where it is 2 small halves.... cheap source of windshield for me

redzcstandardhatch
redzcstandardhatch New Reader
10/15/09 7:01 p.m.

on gutty, we had some CRAPPY plexi and lexan in the rear windows (took it out of storm doors that we replaced)

it was scuffed, etc.

TURTLE WAX YO

we waxed it all a couple times , and it looks PERFECT. just a note for future care..

poopshovel
poopshovel SuperDork
10/16/09 8:43 a.m.
patgizz wrote: the home depot has real lexan now - not sheets large enough for the typical car windshield, but for my truck where it is 2 small halves.... cheap source of windshield for me

Home Depot is WAAAAAAY overpriced compared to plastics suppliers like piedmont.

BeaterBlogDave
BeaterBlogDave New Reader
9/5/12 10:58 p.m.

In reply to Keith:

I wanted to thank you for posting the info and link. I installed a short Lexan windscreen on my Miata using your advice:

http://www.beaterblog.com/2012/09/project-miata-roadster-windscreen.html

mightymike
mightymike Reader
3/4/13 9:20 a.m.

Can anyone comment on how the Lexan "looks?"

I can't open the link in Keith's post. The front glass in my '77 Capri is pitted, scratched and old looking and I'd like an upgrade in look and less weight. This is for a vintage race car, but I want the car to look as nice as possible as well.

I'll do the same for the rear glass if it looks good enough.

Keith Tanner
Keith Tanner MegaDork
3/4/13 9:31 a.m.

I fixed the link. Then you can see the look. Honestly, it looks like glass, the difference is in how well you deal with the edges. Old cars that use a removable rubber seal to hold the glass in place will have the easiest time.

A few more notes:
the 1/4" number I mentioned wasn't chosen randomly. I believe that's what NASCAR requires for a front windshield. It's possible that it's 3/16", it's been a decade. On the rear window, I've used 1/8" happily.
I tried silicone around the edge of my last rear window. It looked good for a short time but then darkened and now looks terrible.
* Instead of foam around the edge, a piece of clear surgical tubing sandwiched between the polycarb and the body of the car does a nice job of providing a seal that looks good, is easy to remove and waterproof. The aforementioned old cars (like my MGB and Mini) would not require this.

81cpcamaro
81cpcamaro HalfDork
3/4/13 9:53 a.m.

I have a 1/8" Lexan windshield in my Camaro (Harwood part). Since I only autox the car, it works great. I do have a center support as it does flex some. 3/16" would be a better windshield choice for higher speeds. 1/8" works for the rest of the windows. I did get mine with Margard coating which resists scratching, but it still can be scratched, unfortunately I know from experience. One note, Lexan isn't legal per DOT for windshields on street cars, other than the scratching part I don't know why they don't allow it. Maybe an impact difference?

I used the 3M window weld ribbon to seal it and screwed it in through the ribbon, no leak problems. When it was new, it looked very close to glass, but there still is a difference, just very slight.

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