Step 1: Build a Press or Get Some Clamps
Water based varnish works well to bond rawhide to polycarbonate. most epoxy is too brittle- and contact cement is too weak- and will both fail a heat/freeze test.
because the water based varnish proved to be the best glue for this application a manual press or clamping pressure had to be used instead of vacume bagging because the rawhide and varnish need to be exposed to air to dry. MDF is the perfect material to protect the rawhide and disperse clamping pressure because it can let air pass.
picture shows a large press constructed of Unistrut from Lord and Sons in San Jose
Step 2: Prepare the Substrates for Bonding
sand the rawhide and polycarbonate with the rough grit sand paper.
in the photo's I used a DA sander with 60 grit sand paper.
Th polycarbonate was clear before sanding, sand it until frosted to remove the hard top layer.
clean off the dust.
Step 3: Glue and Press
use a lot of glue, clamping pressure has to squeeze glue out of the sides during clamping to ensure no air bubbles. Rawhide is stubborn a lot of pressure is needed to force it flat.
clamp in the center first then work your way out to push air out.
Step 4: Admire Your Results
pull the rawhide, polycarbonate and MDF sandwich out of the jig/clamp. the MDF will be stuck to the edges so pull it off it is weaker than the glue in shear strength.