Plexiglass as a Rear Window?

My rear window shattered last week for reasons unknown. My uncle and I cleared out the glass, and put plastic where the window used to be. The quote I’m receiving from many local glass dealers to replace the window is upwards of $600. The car itself might not be worth that much. Has anyone ever replaced a window with plexiglass here? Recommended or not?

Not recommended. Plexiglass will break in a car window application too. If you want a non-glass material for your window, you’re looking for lexan, which is what they use in race cars.

But the problem with lexan is that it scratches easily, so you have to put a protective film over both sides, and of course as soon as you scrape snow off of it (because you no longer have a rear defroster) you will scratch and/or destroy the film, scratch the lexan, and have to start all over.

Or in short, just replace the glass.

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I have used Plexiglass only on a race car.

It shouldn’t be used on a street car. If your location requires safety inspections, it will not pass. If you get pulled over by the police for anything, they might cite you for the Plexi. They might tow it to impound as unsafe.

I’ve used this material as a replacement for a broken windows.

https://www.homedepot.com/p/OPTIX-36-in-x-48-in-x-093-in-Acrylic-Sheet-MC-09/202038045

Tester

Is it in a hatch? You might be able to replace the whole hatch for less.

My understanding is that the glass helps to provide some of the structural integrity of the passenger compartment, so it seems like you’d be giving that up by using something less sturdy.

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Windshields provide structural integrity to a vehicle.

Side glass and back glass does not.

Tester

My concern is that if the non - glass material is subject to strain that causes it to break the pieces flying
loose could cause serious damage.

I did know someone who found a rear glass at a salvage yard but they broke it trying to install and ended up at a glass shop anyway.

I was going to say, you can get windows at a salvage yard cheap. But you have to remove it then install it without breaking it which is very difficult.

I’m skeptical of the claims in the Home Depot ad. Acrylic polymer may be stronger in tension, but not in compression. The claim that the product is stronger than glass is misleading. I can’t imagine when a rear window is under tension, but I can think of times when it is in compression.

Then that would mean you have an issue with the Home Depot.

And not with me.

Tester

I agree.

Oh, no! I submitted the dreaded short message and I was chastised by the Short Message Police!

Is there a requirement for vehicle windows other than the windshield that they shatter into really small pieces when they break? Or does that only apply to the windshield?

The windshield is laminated to reduce shattering. The rest is tempered and will break into small pieces.

Yeah I was going to say check out a salvage yard. Back in the day I paid $25 for a windshield and paid a body guy $20 to put it in.