"Jim Burns" wrote in message
...
When we purchased our Aztec, one of the things that we promised to
update/upgrade/replace was the two piece windshield with a new 1/4" one
piece. This will raise our compass up and move our OAT gauge to the
pilot's
side window.

Well, today it came and is sitting in my computer room. I've got the STC
and the install directions so next week when the Azzy goes in for it's
annual, with the help of our A&P/I we'll take out the old and put in the
new.

The install directions look pretty straight forward. Remove the old, trim
centerpost for remounting compass, clean out the old seal and silicone,
test
fit, trim, test fit, trim, ect. Install new seal, silicone, remount
compass, swing compass, mount OAT in side window. Use plastic cutting
drill
bits, 100% silicone caulk, new hardware, ect. Yeah, I'm "sure" it will be
that easy... not.

So, does the group have any collective wisdom, horror stories or vast
experience replacing windshields?

Thanks!
Jim

THE most tedious job in building my RV-6 was fitting the windscreen and
canopy. This was caused by the canopy being blown by party A, the airframe
being constructed by party B (me), and the canopy frame being welded by
party C. Your task may be easier because you're only trying to fit together
two mismatched components instead of three.

Remember that plexiglass is fragile and expensive. To save yourself some
heartache, take heed of the following:

If you leave a stress riser (a nick for instance) on an edge, and put the
plexi under stress, it'll crack in a heartbeat. To avoid this, make sure
and sand or scrape off all sharp edges and dress out notches, even as you
fit and refit the glass. Before final assembly, make sure you really, really
clean up the edges of the plexi. They should be smooth to the touch.
Sandpaper or edge scrapers work well for smoothing edges.

The warmer you get plexiglass, the less brittle it becomes. I did most of
the work on my canopy in an 85 degree garage with a space heater running
inside the cockpit. No fun at all.

There are special plexiglass drill bits that don't "grab" the plexi. Make
sure you use those, particularly in any size over about 3/32. Unibits also
work well in plexi.

The instructions on my canopy were to cut it by making multiple shallow
passes with a cut-off wheel. You don't want to create stress risers by
overheating the plexi at various points along the edge.

Some folks recommend flaming the edge of plexi for a good smooth edge. Even
more folks say this is a terrible idea because you cause dissimilar heating
in the material and stress risers.

Enjoy.

KB