4.3.2 Polishing
The very strict space restrictions on the size of the PV required the joints
between the light guides and the staves to maintain the 3.175-mm thickness of
the staves. This meant that any epoxy on the outside of the joint needed to be
removed and the surfaces near the joint polished to leave a smooth, reflective
surface. Epoxy was typically allowed to dry on the outside of the joint as an
assurance against air bubbles.
The polishing process involved several steps. First, the larger pieces of epoxy
were removed with a razor blade. Next, fine grain sandpaper (~600 grit) was
used with water to remove any residual epoxy and make the surface even.
Finally, the joint was polished using a buffing wheel and a polishing gel
(equivalent to 10,000-grit sandpaper).