On Tue, 29 Dec 2009 21:29:07 -0800 (PST), Frogwatch
wrote:

A previous thread mentioned Bronze portlights (absurdly heavy) and
also plastic ones (maybe not strong enough) but the glass/plastic
composite G10 is certainly strong enough. Might be interesting to try.

A very quick look shows G10 with a tensile strength of 40,000 PSI
taken "lengthwise" and 35,000 PSI "crosswise". I assume that these are
taken in line with and across manufactured slabs.

Cast bronze, on the other hand, varies depending on the specific
alloy. An alloy, referred to as a "general purpose bearing bronze
alloy" is listed as having a tensile strength of 35,000 PSI.

Compression strength is radically different though with bronze listed
as having a compressive strength of 20,000 PSI while G10 lists a
"flatwise" compression strength of 60,000 PSI and a edgewise strength
of 35,000 PSI.

Hardness is listed as Rockwell M 110 for the plastic and Brinell
Hardness of 55 - 65 for the bronze. Rockwell and Brinell tests are not
directly convertible and so far I can't find any cross reference data
for these two ranges.

From a materials point of view there seems no reason not to use G10.
Whether it will stand up well to UV is another question. some plastics
do not.
Cheers,

Bruce
(bruceinbangkokatgmaildotcom)