From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] LNC4 windshield trimming
To: lml
Date: Wed, 27 Nov 2002 09:23:51 -0500
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Posted for Bob Pastusek <rpastusek@htii.com>:

Skip,

We used a new/sharp blade in our band saw to do this. It's definitely a
two-person job, and requires a cloth or other soft pad on the saw table to
protect the windshield, and the normal amount of patience for airplane
building... The windshield is even more sensitive to trimming than the side
windows because of the compound curvature, so take off small slices at a
time. When it finally "pops in" around the thicker part of the fuselage top,
you'll have a gap between the "joggle" and the windshield edge. You'd like
to have this as small as possible to maximize the bond surface area.

We had some difficulty getting the window to lay completely flat against the
fuselage opening in one corner. We had to sand/grind off the outside
(bonding surface) of the window around the lower left corner (or was it the
right corner?) to about 1/4" thickness at the outside edge around the curve.
While you can force it down with the bolts during bonding, this stresses the
windshield and can cause the bond to separate when you take the bolts
off--the Hysol bond between the Plexiglas and the carbon is not nearly as
strong as between carbon and metal, etc.

We bought a handful of cheap Phillips head screws, large fender washers and
wing nuts for this job. They are SO much easier to work with around the
Plexiglas and Hysol, and hand tight on the wing nuts seems about the right
bonding pressure? After we put the windshield in place and installed the
bolts loosely, we placed the top on the fuselage bottom and clecoed it in
place well, then tightened the clamping bolts. While this procedure is not
as critical for the windows, you'll find that the windshield/opening
definitely changes shape a bit when you clamp it, so holding the shape to
match the fuselage bottom is more important.

One last tip: Take some time to carefully radius the Hysol squeeze out
between the windshield and fuselage opening on the outside, then lay a thin
strip (1/4" or less if you can cut it) of peelply over the Hysol joint. It
tends to smooth the Hysol, makes a nice radius as it absorbs a bit of Hysol,
and requires minimum sanding afterward to clean up. Important to have the
right amount of Hysol/radius to make this work well--our last window was the
best.

Hope this helps!
Bob Pastusek