If you have top bee space the type of
glass viewing board
that is made commercially, is of no use as the bee space will be so
great that the bees will quickly construct brace comb. However a
different approach is possible using 9 mm thick Perspex
(poly methyl methacrylate). The 9 mm thickness is necessary to
obviate sagging in hot weather. With top bee space no rim is actually
required so the drawing below shows a Perspex square 460 mm on a
side with a central 33 mm hole.
A wooden rim can be applied using countersunk screws to
make a one sided device. As the rim is there only for strength and
stiffness it's dimensions are not critical and the parts can be of any
available timber. The rim parts in the drawing below, depicted upside
down for greater clarity, are 9 mm thick and 32 mm wide.
They are arranged 'nose to tail' and so all four are 428 mm long.
Transparent Crown Board for top bee space use
Originated... 21/22 May 2002