Why does lexan have such a bad rap?

Many years ago I bought A radical custom.A sectioned 49 Stude coupe with a big bubble top.Plexiglass or Lexan.The car was great to look at,but instant heat stroke in the sun.A completely chromed '55 Pontiac dash that reflected off the bubble.Wipers not an option due to scratches.I loved that car,but got rid of it rather quickly.That's an extreme case,but convinced me to avoid that stuff.

 

I think some of these guys have Plexiglas and lexan confused. Plexiglas is what will yellow and break but lexan is what the U.S. Air Force on thier fighter plane so unless they screwed up you will be good to go with lexan. As far as being legal, I have 2 street cars with lexan in them.And if you do get light scratches or yellow film there are plastic polish, like one would use on motorcycle windshields.

 

Neicly put and to the point,I've used Lexan in my race cars for many years[your not alowd to us glass of any kind]

 

But it will break. Had many a Windshield on a race bike do it over the years. And it does scratch really easy...

 

I say unless someone has true experience with this shattering ,ignore it.Ive used Lexan(name brand) and it will scratch easy but wont break with even intent to do so.
-G-

 

Go to your local civil airport, and look at how many 150+ mph Cessnas/Pipers/Mooneys/Beechcrafts have lexan, acrylic, and p/c windshields, and if you look for laminated saftey glass in an aircraft, you'll be looking for a looooong time.

The avarage age of a civilian aircraft in this country is 30 yrs old, and many of them are still runnung their original windshields.

As for care of lexan, acrylic, etc., I would disregard the advice of the motorcycle shop, and go straight to the FAA airframe maintenance manual.

 

I've worked around Lexan for GE, who invented the stuff. We used it on utility meter covers. It will scratch, and get frosted by blowing dust or sand. It is however very strong. I tried hitting one with a good sized hammer, and all it did was bounce off. Some of our customers wanted it because it was vandal proof, unlike the usual glass covers were.

 

I was thinking I might have a few holes drilled at the corners just for looks. Glass is more expensive to drill. Just a thought...

 

Lexan is a brand name for polycarbonate. Plexiglass is a brand name for acrylic. Polycarbonate will not shatter and can be bent with a sheet metal break without heat. Thick polycarbonate is what is typically used for "bulletproof glass". Acrylic will shatter and has to be heated to bend. DO NOT USE acrylic for a windshield. When I was an industrial design student I used both of them a lot. Acrylic will also polish back to clear with either an abrasive or heat. Once it's scratched polycarbonate always has a dullish finish.

 

I personally wouldn't and havent used it for a windshield but my question is aren't airplane windshields made of Lexan? Airplanes go a lot faster than cars and get more abuse due to rapid temp change .Also birds slamming into them at high speed.I would think wipers would scratch it.Any airplane mechanics out there with a responce to this?

 

I have used lots of lexan over the years and I would never use one on the street.

The idea that they last forever in a race car or airplane has little of no bearing on a street car, neither an airplane or race car will spend much time on the highway.

Lexan will not shatter, however if not oriented the correct way it will crack over a bend. On a tight bend it will get streaks inside the lexan in the direction of the grain.

A 4'x2' section of 1/8" lexan will grow as much as 3/8 across the grain on the sunlight. If you fit it on a hot day and drive it on a cool day, it may just join you in the front seat!

The cheap stuff from lowes will not have any scratch coating on it, nor does it have a uv protection.

I'll reserve my opinion of the car itself as its not very flattering.

 

I used 3/16" lexan in my side windows of my old autocross car. Its been sitting in the sun for about 2 years and they're still crystal clear. In my experience its hard to scratch, but if you do manage to scratch it, its almost impossible to buff out. The glass company I bought it from told me it was better than glass. I took theyre word for it. However they were talking about my application, not about windsheild use

Oh, and it cost $60 and they cut them from my cardboard templates.

 

Sure he can, there are companies that make custom one off windshields all the time. If you're going to go through the work to make a car wider than it originally was, certainly the windshield isn't the time to cheap out and do something crappy and stupid.
Fact is Safety Glass is the ONLY approved product for a windshield and i actually believe that may be a Federal Law. There's a reason for it!

As for using it in race cars and Airplanes - that is apples and oranges. I know that my buddy that works for a NASCAR team says they replace the windshields pretty regularly because they get so pitted and hard to see through. As for airplanes, have you ever looked through an older airplane windshield? They look like crap! There also isn't anywhere near as much junk in high altitude as there is on the highway. They also don't need to be as optically clear as there aren't anywhere near as many obstruction and diversion when flying.
AND you do see jets with broken windshields on the news quite a bit

 

LOL , isnt THAT an opinion?


same thing if i said.

" im not going to tell you how fat you are, cus it might hurt your feelings"

 

Im glad someone finally put down the truth - Lexan is bullet proof (note it doesnt say 'resistant' it says bullet proof) and it DOESNT turn yellow!!

Years ago after an a&&hole shot up the front of our house I had a sheet of 3/8's Lexan installed over the picture window. In 20 years it did not change color or warp and it was optically OK . Fortunately we never had to find out if it would stop a 44mag but I was assured that it would when it was sold to me.

I think many of these references are to plexiglas. Plexiglas is NOT the same as Lexan.

 

Quote:
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt2 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by 49ratfink
the point is this guy built a car that can not have any type of glass windshield installed no matter what he trys
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Sure he can, there are companies that make custom one off windshields all the time. If you're going to go through the work to make a car wider than it originally was, certainly the windshield isn't the time to cheap out and do something crappy and stupid.


from what I hear those custom made windshields from a pattern are like 3 grand. they go in cars built by guys like Oz Welch.

that windshield opening is not symetrical from side to side and has a dip in the center.

as for doing something crappy and stupid... I'd say that's already been done.

 

Uhhhh... no! Not all Lexan is bulletproof. The different thicknesses are rated to specific caliber. But because it is Lexan do not assume it is bulletproof. Depends on the thickness and the caliber.

The physical advantages of LEXAN resin begin with its strength and extend to its resistance to the elements of:

* Heat (up to 212°F/100°C)
* Cold (down to -40°F/-40°C)
* Water
* Weather
* Ultraviolet light
* Flame (Underwriters Laboratories UL 94V-0 listed)

It's pretty much shatterproof in it's pure form, but when it's molded and cut, and when its structure is compromised, it is possible to crack, and even in extremes, shatter.

1/2 half inch will stop up to a .38 special from as close as 4 feet away, once you get into the magnum calibers you need to get into 1" plus thicknesses.

Just a few things from around the web...

 

For the most part I think you guys are missing the point. Lexan doesn't have a bad rap, or a bad reputation. It's a great material, with many uses. It's when it's used to finish a botched chop job that it looks cheap and crappy. Please don't take this personally, but I was shocked at the other thread about this car. Everyone seemed to be encouraging this type of work. I agree that it takes balls to attempt modifications of this level. However. a little research and planing might have prevented the car from turning into what you have. If your happy with it, great, drive it, enjoy it. But don't be surprised by negative reaction if you take it out in public. It's not the lexan, it's the car.

 

Percy's Speedglass is another source for scratch resistant polycarbonate.

 

lexan/polycarbonate is being use on some of the newer cars. As a retired fire fighter and an instructor that teaches vehicle rescue and new technology for vehicle rescue. There is part of the course that deals with this type of windows. some of your high end sports cars and Ford have been using this stuff in there cars and trucks. This stuff is strong and there are two ways to deal with it. 1st is taking a Rotozip and cutting it and the second way is freezing it with a CO2 fire extinguisher and hitting with something hard. As far as I know they are not using for windshield yet but there is talk about.

I have encounter this stuff. One night we responded to the truck fire on the interstate. The truck happen to be a car carrier with some high end sports car on it. The fire was in the cab area of the truck and the car above the cab. I set a ladder to the car and went up with an axe to break the side window. I hit it three times as hard as I could and all that happen was the axe bounced off the window and never broke it. finally had to get a CO2 extinguisher to break it.

Ford has been using it in the side windows and hatch window of some of there small car and the rear and side cargo door windows in there vans.

Some of the car that been using it. Lexus, Porche, BMW, Marcedes, Ferrari, and some other.

 

That coupe was originally built back in the 60's -70's with the side/rear blue plexiglass windows with the holes. The new owner wanted to keep them. Not a Circle City fabrication.

Terry

 

I'll probably take a whuppin', but I agree with you. Plexiglass is the stuff that break easily into shards, while lexan will withstand about anything you can do to it. One thing that it doesn't like is lacquer thinner, as it tends to melt and mottle the surface. I also think the aircraft industry uses lexan in a lot of applications. Also, the fronts of soda machines are made of lexan, today, and you can bet those things take a beating. There are also products on the market that are very good at removing scratches and other surface imperfections from lexan. With proper care of the lexan, safety shouldn't be that much of an issue.

 

Take a look at the windscreen on this Rod. Looks to me like its Lexan.

Re: Foose's P32 - In Flight! Video with V-12 Sound

 

I agree with hotroddon and zman on this one, but I have to share my opinion. I think what happened here is that you're in over your head based on the progress so far. I think the cars concept is great but it's a gigantic undertaking to do something like this, widen a car. With the progress you've shown so far it's my opinion you are in to much of a hurry to see an end result. Hence, disaster has struck! You have an almost insurmountable amount of work to do before you even think about a windshield. It doe'snt mean it cant be done but getting to this point and then realizing the windshield is going to be to expensive to make the right way shows really bad planning. If you make a template out of aluminum you can get a windshield made, but it wont be cheap, and you first have to get things straight and square. Slow down! If you're doing this kind of build on a tight budget it may be a 5 or 6 year build to do it right. The general consensus here is that glass is the way to go, and it is the only legal way to go, period! That said, I'm going to throw in another .02 cents worth, what about grafting the windshield surround and glass from the frame doner car. Then you would have alot less work to do and when all that bad shit like 2x4s and pheasants and whatever else hit the GLASS , you can go to the boneyard and get a new one. That may work for the back glass to. I don't want this to sound like I've never made any bad judgement calls in any of my builds, I have. What I've learned is that when I slow down and think it through it always seems to go smoother. I think that this build could turn out good, if you take your time. Good Luck!!!


Oldschool66

 

What about curving Lexan for temporary use to help get pattern for real glass to be cut/made. Anyone in California have names of custom glass makers-curved windshield for chopped '54 Chevy ??

 

OK so how much thickness to stop a 155MM round or an RPG??

Generally speaking it IS bullet proof. Obviously you have to chose how much bullet you need proof from!

Garon Plastics in Baltimore assured me that 3/8 was enuf for a 44mag, at
a distance of 40feet from the street to the picture window.

 

Ive had a lexan rear window in my TVR for about 12 years now. The reason we went with lexan is cause of weight and availibiltiy compared to a large glass rear window. I havent had any problems with it and dont see any fading. Alot of people mix up plexiglass with lexan

I would use it in a build but its not for everyone I suppose. Ive always cared for mine by waxing the window.

 

Boy, you guys that worried about bullets must live in tough neighborhood.
Just found a place online in No Cal called Tri Valley auto glass that cuts glass for chopped tops. But, opening must be in shape of some model car existing glass. Do not make custom glass for cusom installation. like a wide body.

 

well my experience with true lexan is very good I used to race an asphalt latemodel and we ran lexan "glass" and it is super strong you can bend it in a break past 90 degrees and it wont break we made fender praces out of the scraps . the only thing I would recoment is get the "Mar Guard" type Lexan it is a coating that is put on during manufacturing that resists scratching . if you dont use the coated lexan it scratches very easy . even a terry towel will scratch it , i found this out the hard way when i ordered the uncoated type the first time to save money and the second time racing the windshield had the "spiderweb scratches" all over under the lights . air craft windows are made of Lexan