On Sun, 25 Oct 2015 06:39:00 -0600, wrote:

I have a truck topper (Hop Cap brand), that has the typical rear window

We call that a cap.

that lifts up (above the truck's tailgate), and stays up by those small
shock absorber looking things on each side.

gas struts iirc.

The frame of this window is aluminum. The window material is a tinted
plexiglass. Yesterday I had some boards on the back and the window fell
(those shock absorber things are weak).

Especially in cold weather.

The plexiglass hit a board and a
piece of the plexiglass broke and fell out.

I'm going to price a new piece of plexiglass. It wont be tinted, but

Besides plexiglass, you can get Lexan, although that is only one brand
name. Wikipedia's Lexan entry will tell you the generic name.

As to price, if you can find a plastic store, it will have the best
price. In the whole city of Baltimore, over a million in the met area,
there is only one plastic store, but it has a lot of variety** and the
staff is real nice***. And they had quarter sheets, after someone
else bought the rest of the sheet. **and will order whatever they
don't have, but you have to order a 4'x8' sheet. (I mention this for
future projects.) ***Sometimes the quarter sheets are in the back,
but other times, they or smaller or all mixed together in racks in the
front. Sometimes they give me a piece from the racks for free, even
though I don't ask.

Lexan comes in tinted. It's less likely they'll have it in stock, less
likely they'll have a partial piece, but ask.

Maybe mor e important is that it come in UV resistant. So it won't
get brittle with age.

But really, you might just want whatever you can get a quarter sheet
of. I guess they'll sell a quarter sheet of anything but maybe
charge about half the price of a full sheet, something like that. If
they already have a left-over quarter, they'll charge a quarter of a
full sheet, at least that's what the store here does. (People like
you and me are not their big customers, fabricators are. and maybe
glaziers.)

Last summer I tried to make a new rear window for my convertible. But
the design of the 2000-2002 Toyota Solara did not leave enough room
for the window. That's how it broke, just by lowering the top. Later
years they made the window shorter, top to botoom.

I think I paid 20 or 30 for a quarter sheet, probably both. I
actually bought two pieces. I didnt' allow for how strong lexan is,
and I bought 3/16" maybe. Then I decided 1/8" was plenty thick, that
if it sagged (remember it's held up only by cloth at the sides) it
would still never break, so 1/8*** was enough. But by the time I got
it small enough to fit in the well, it was too small to be able to
tape it into place (using VRB tape (or some initials starting V, Very
Strong Bond, or something.) So I ended up buying vinyl sheet at a
fabric store, and sewing it in, and a year later, it's already cloudy.
Also the very heavy thread that my friend an upholsterer gave me broke
in one place a month ago, and 2 more places since. I would have been
better off with button hole thread, I think, which is cotton wrapped
polyester, or something like that. I'll repair it with that.

***For you, the rubber grommet might be the deciding factor on
thickness, but your window is held in place a lot more than mine. 1/8
should be plenty, unless someone hits it so hard it bends and pops
out. It will bend in the middle horizontally but not vertically, I
think.

that's ok. But I'll have to get it professionally cut because it has
round corners.

I agree with Clare. An electric sander of some sort will make nice
round corners. Write the line on with crayon or eraseable marker and
sand up to the line.

But if the plexiglass is costly, I may try to just glue
that cracked piece back using epoxy. (unless there's a better glue for
plexiglass).

Gluing the edges? Maybe. Plexiglass if that's what it is is easy to
glue and "dries" immediately. Acetone is the glue. It dissolves the
plexiglass and you push the pieces together, or at least make them
touch firmly, and take the time it takes the acetone to evaporate,
multiply 10 seconds by 2 or 3 iirc and it's dry. Plastic stores
will have little bottles with iirc perfume in them so they don't smell
the same. Use with adequate ventilation. Bad to inhale.

Dont' blame your self too much for breaking it. Plexiglass gets
brittle with age, more that lexan. (In 1973, I did a larger car
window with plexiglass. I'd paid to get vinyl put in then parked
facing north for 7 weeks (which meant the convertible rear window
faced south, the sun. ) and it got cloudy during those 7 weeks. So I
gut a hole and pop riveted in a trapezoid-shaped piece of plexiglass.
Maybe I covered the edges with tape. A couple years later I barely
hit it and I broke the corner. I didn't know about acetone then, and
lexan might have been new. Well, it was invented in 1898 and
production started in 1960, but it still might have been new for
slob-level use. I can't remember where I bought it, lived in Brooklyn
in 1973

And Lexan is "polycarbonate".

Either way, I want to take the whole window off the topper so I can work
on this on my workbench, rather than trying to do it in a vertical
position, on the truck. (not to mention that it's cold outdoors).

A friend with a heated garage? A public garage that's sort of warm?

In Brooklyn, I noted a public garage that had electric outlets, but
never ended up needing that. Oh, except once I couldnt' get the top
up and it was about to rain, so I scampered to a public garage and
fixed the top.

I see there's a clip on each of those shock absorbers, but I can not see
how the hinge holds it in place. The hinge is NOT screwed on, it's part
of the assembly. Looking at it from the side, it's sort of like a round
sleeve inside a larger round sleeve with a slot in it.

I thought that maybe it would slide out sideways (toward the right or
left of the truck), but that dont appear to be the case. (I did not yet
remove the shock absorber things). I'm wondering if it needs to go
straight up, pointing toward the sky..... (just a guess).
So, I thought I'd ask on here before I try anymore. Its probably simple,
but first I need to know the trick.

Has anyone on here done this?

Thanks