Tim has provided a pretty good summary of the process. Some notes on
canopy transparencies in no particular order:

* As Tim pointed out, mounting canopies takes time and experience to do
right. As with most things, the best results are had the second or
third time you do it. Your best bet is to find a shop that's done it
before so you don't end up paying for the shop's education.

* Though the work is fussy, takes rather a lot of time to do properly,
and requires a good eye and somewhat delicate touch, it can be done in
the home workshop environment. If you've done good-looking bodywork
with Bondo and paint, you can probably mount a canopy. At very least,
you can probably do some of the prep work. But consult with your A&P
before starting. If you've done owner-assisted annuals (the best kind,
I think) and have a good relationship with the A&P, they might be OK
with it. Or, they might not. Ask first to avoid surprises.

* Usually the preferred bonding techniques and materials are shown in
the maintenance manual. You can also pick up some general hints by
looking at the tech notes for different gliders. The DG tech notes in
particular show a neat trick for using foam tape for controlling
squeeze-out of the bonding resin.

* Bonding the transparency onto the frame without having the frame on
the fuselage is very risky, and I've seen it result in an
embarassing-looking assembly that barely fit onto the glider at all. I
definitely don't recommend it. Canopy frames tend to be fairly
lightweight parts, and a lot of the strength and stiffness of the
canopy assembly comes from the transparency. Also, the frame is often
painted black so it sometimes gets hot and takes on a warp that only
shows up when it is separated from the transparency. All the big
companies have tooling that emulates the cockpit rail that they clamp
the frame to when bonding in the transparency.

* Acrylics are much more crack-prone when they're cold. If you feel
tempted to work acrylics such as Plexiglas, don't do any cutting,
drilling, or filing operations unless the plexi itself (and not just
the room it's in) is warmed up to at least 70 degrees F and preferably
in the 80s F.

* If the preferred bonding resin isn't shown in the tech notes and you
have to choose your own, I suggest _not_ using an epoxy thinned with
butyl glycidal ether (as are most laminating resins) - it crazes the
acrylic. George Applebay has recommended Epon 828 kicked 2:1 with
Versamid 140. I haven't tried it myself, but I will.

* Last time I checked, the manufacturers were paying 500 to 1200 Euro
for transparencies of various sizes in lots of ten or so. Contrary to
popular belief, Mecaplex quite often has the best prices in Europe for
the raw transparencies. The big markups start when it leaves Mecaplex
or wherever, and the glider manufactuer and all the middlemen and the
shippers and insurers get their cut. That's just the way commerce
works.

* Right now acrylics sheet prices are spiking to follow oil prices, so
be prepared for some degree of sticker shock.

* Anybody who wants is welcome to develop their own tooling and place
an order for ten or so and become part of the game themselves. But I
don't think that you can contact Mecaplex directly and order Discus or
ASW-27 canopies. Usually, the glider company develops the canopy
tooling and then hands it off to the transparency company with the
agreement that they will only make transparencies on that tool for that
glider company.

* Anybody who ever thinks of making their own canopy transparencies
should count on not getting usable results until somewhere between the
third and sixth attempt. It's a tricky business, and the major players
guard their trade secrets jealously. Way more often than not, the most
cost-effective way of getting a good transparency is to buy it from a
reputable firm such as the sailplane manufacturer.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24