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Lexan windows

S

Stumpalump

NAXJA Forum User
Location
Franktown Co.
How much weight will I save if I replace the rear glass and rear sides of a four door XJ with lexan? Any body try this or other things to reduce a little weight without hacking the vehicle to death?
 
I just replaced a few windows with Lexan for a different reason:

IMG_2017.jpg


I would say the weight savings isn't real huge. Has it's advantages (light, easy, cheap to replace) and disadvantages (yellowing, scratches easy). If interested in the rear qtr windows, PM AZXJ on here. He used to make these and may have some left over. For the small window in the door, I just bought a sheet and cut it to fit.
 
thought it was about half as heavy? And if it's real lexan and UV coated it shouldn't yellow. Speedglass is pretty good stuff for resisting scratches and has a UV coating.
 
Weasel said:
thought it was about half as heavy? And if it's real lexan and UV coated it shouldn't yellow. Speedglass is pretty good stuff for resisting scratches and has a UV coating.
Click to expand...

It probably is half as heavy, but since the glass doesn't weigh that much to begin with, you might want to look for weight savings elsewhere. I just pulled all three of those windows you are talking about off my parts XJ and I'd say they couldn't weigh more than 40 or 50 pounds all together. But I am a tough guy and my bicepometer hasn't been calibrated lately. :D
 
About 20 years ago the rear window to the topper cap on my Dad's truck was broken (damned thieves). He replaced it with Lexan (the real deal from GE if memory serves me right). I can't remember how long it took, but after 5 years it was virtually impossible to see through. Hopefully with advances in the last 20 years this isn't as much of an issue. Unfortunately it does make me leerie of Lexan.
 
we have lexan windows at work and after the 6-7 years i've been there there is no discoloration whatsoever talk to a sign shop for your needs they may even have the weights of the pieces for you to compare
 
If using the same thickness Speedglass is roughly 1/2 the weight.
1/4":
Glass - 3.4 lbs/ft^2
Speedglass - 1.67 lbs/ft^2

Since the speedglass is stronger you could run a size or two thinner.
3/16:
Speedglass - 1.34lbs/Ft^2

So my XJ (2 door) has ~120ft^2 of glass.
@ .25" Thick = 408 lbs
@ .1875" = 300 lbs

so replaced with Speedglass
@ .25" = 200lbs
@ .1875" = 157lbs

IMO thats a huge chunk of weight you can loose, if you have the money. Even better is it's loosing weight from the upper half.
 
Don't know if it will pass state inspection, if you have state insp. where you're at. DOT requires tempered or laminated for side lites. Lexan tends to stratch VERY easily, and clouds if you use any ammonia based cleaner.
 
And you sure as hell don't want to get in an MVA with those. State inspections require DOT legal glass for a reason. It's to make it possible to drag your bleeding ass out of a vehicle safer. Side window glass shatters that way for a reason. Windshield glass shatters that way for a reason. If I HAD to go lexan, it would be behind the C pillar only. If I NEVER had passengers in the rear, I still wouldn't put it in the doors. Sometimes the only way to keep your spinal column from severing nerves is to have someone hold your head from the rear seat. Sometimes, the only way in is through that rear door window. I want the medics to have as little trouble as possible getting to me.

Have fun with your Lexan though. I hope to god I don't get sent on the call and have to watch you die because you wanted to save a couple of pounds of vehicle weight. Knowing that you may have lived if you had just left the glass alone. I've seen enough people die for stupid reasons.
 
Jesterbomb said:
And you sure as hell don't want to get in an MVA with those. State inspections require DOT legal glass for a reason. It's to make it possible to drag your bleeding ass out of a vehicle safer. Side window glass shatters that way for a reason. Windshield glass shatters that way for a reason. If I HAD to go lexan, it would be behind the C pillar only. If I NEVER had passengers in the rear, I still wouldn't put it in the doors. Sometimes the only way to keep your spinal column from severing nerves is to have someone hold your head from the rear seat. Sometimes, the only way in is through that rear door window. I want the medics to have as little trouble as possible getting to me.

Have fun with your Lexan though. I hope to god I don't get sent on the call and have to watch you die because you wanted to save a couple of pounds of vehicle weight. Knowing that you may have lived if you had just left the glass alone. I've seen enough people die for stupid reasons.
Click to expand...
Does that mean I should get rid of my Lexan windshield? :D
 
jesterbomb said:
And you sure as hell don't want to get in an MVA with those. State inspections require DOT legal glass for a reason. It's to make it possible to drag your bleeding ass out of a vehicle safer. Side window glass shatters that way for a reason. Windshield glass shatters that way for a reason. If I HAD to go lexan, it would be behind the C pillar only. If I NEVER had passengers in the rear, I still wouldn't put it in the doors. Sometimes the only way to keep your spinal column from severing nerves is to have someone hold your head from the rear seat. Sometimes, the only way in is through that rear door window. I want the medics to have as little trouble as possible getting to me.

Have fun with your Lexan though. I hope to god I don't get sent on the call and have to watch you die because you wanted to save a couple of pounds of vehicle weight. Knowing that you may have lived if you had just left the glass alone. I've seen enough people die for stupid reasons.
Click to expand...

I recommend strapping your knees to your chair before posting. ;)
 
BlackJax said:
I recommend strapping your knees to your chair before posting. ;)
Click to expand...

Duly noted. Yeah. Um. I wish I could go back and tone it down some. I just feel really strongly about death. Hey, it's just one man's kneejerk opinion right? I am sure there are lots of times and situations where nothing would go wrong. Trail only vehicles, Trailer queens, whatever. I just... yeah. I apologize for the... vigour of my first reply.
 
If anyone was payignattention the Speedglass stuff I mention is pretty much scratch proof. Peterson's used it and couldn't scratch it with steel wool. And there are better grades then lexan for this.
 
Weasel said:
So my XJ (2 door) has ~120ft^2 of glass @ .25" Thick = 408 lbs
Click to expand...

Ain't no way, sorry, you counted something wrong. Windows are about 14" high, 1.2 feet. You'd need a hundred linear feet of windows to get to 120 sqft.

Realistically, it's maybe seven feet on each side, four each for windshield and back glass. 22 total, by 1.2 makes 26.4 sqft.

Changes the numbers a bit, sorry.

Robert
 
yeah i was going to say, you could put lexan covered in expanded metal and still not go over the wieght of glass...but then youd really be effed in a "mva". lets see that get smashed
 
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