Wonder how silicone would do? They use it to make home aquariums. I
use it for holding lots of things - small sheet metal covers for wing
bolt holes, txpdr antenna metal base to my composite plane.......
Holds great. And it flexes slightly to help with differential heat
expansion (your cracking problem?). Just let it cure overnight.

On Nov 4, 11:09 pm, Larry wrote:
I am planning a "touchy" repair job to my canopy. I've done some test
sheet acrylic bondings with acrylic IPS Weld-On (#16). I don't like
the ugly bubbles and noticed some fine plexiglas stress cracking on
one test piece. Is there another sort of cement (eg. Weld-On #40)
which would make for a better looking bond between 2 sheets of .080 in
plexiglas? Thanks.

Larry