On Wed, 11 Sep 2013 10:56:38 -0700, "Paul Hovnanian P.E."
wrote:

Ed Huntress wrote:

On Wed, 11 Sep 2013 08:17:46 -0400, "Jim Wilkins"
wrote:

"Artemus" wrote in message
...

wrote in message
...
So I have this wild idea to make the rear window on my Scion xB
openable. It is of course made from tempered glass and so making
holes
in it won't work. I am pretty sure I have seen handles glued to
windows on cars but I'm not sure. The rear window is now just glued
to
the rear hatch. I'm thinking that if it was removed a gasket could
be
installed, and hinges, gas springs, and a latch installed. So can
this
be done? Anyone here done this? I'm pretty sure that making the
hinge
assembly, latches, and handle won't present any real challenges.
After
all, I do have a complete mahine shop and I am a machinist.
Eric

Think about the other end. Windshields are glued in with a silicone
adhesive and the rear view mirrors are glued to the glass too.
Art

The latch, wiper, struts, brake light and hinges on my Honda's glass
upper hatch are attached with thru-hole fittings. The heater grid
contacts are bonded to the glass.

Art's point, though, is that "tempered" glass is very highly stressed.
The surfaces are in compression and the core is in tension. If you
drill it, or even scratch it deeply, it *may* propagate a crack
through the glass and shatter it into chunks (not sharp shards).

Glass is not among the materials I study much, but I suspect that, in
production, they either do their drilling while the glass is in the
annealed state, or they have a way of locally annealing it after
tempering.

As for gluing to it, there has been good advice in this thread. You
can get a very strong bond with the right materials and technique.


The glue may need to be somewhat flexible to allow different rates of
expansion between the glass and the frame. Or arrange the frame to be made
in parts than can slip or flex slightly as the glass expands/contracts.

If the rear window is already held in with glue, just use the same stuff.
They've already solved that problem.

The other alternative is to make a frame with a flange that will mate with a
standard windshield rubber gasket. The glass sits in one slot in the
gasket, the frame in another. Turning the gasket around (frame on the
outside, glass toward the inside) might allow the face of the rubber gasket
to act as a weather seal against the car body.
I keep thinking about this even though I'll probably not do it. My
thinking is that the frame should have a flange that protrudes into
the car interior about .5 inches. It should also have provisions for 8
clips, two per side, that trap the glass in case of glue failure. I
doubt that the glue would fail because I would be using the factory
glue. The flange is for stiffness and maybe for sealing. The way the
hatch is made provides for a standard type of seal that is already
being used in cars that have an openable rear window. I want the
opening window so that I can carry long items (over 8 feet long) and
so that I can have really good air flow on hot days. Of course the
real reason for this type of mod is to show off to all those young
whippersnappers out there who have one of these cars and the only
things custom are bolt on items. I have already figured out how to add
a cruise control that rotates with the steering wheel and the last of
the radio control parts just arrived Monday. I have bench tested the
wireless cruise control buttons and they work as planned.
Eric