Re: Acrylic viewing dome

[Dave Everett <deverett@idx.com.au>]

At 08:15 PM 12-03-98 -0800, you wrote:
>Ken is correct that Polycarbonate is tougher (higher tensile strength and
>impact resistance) than Acrylic. However, it's darn near impossible to
>polish once it gets scratched. This may be the optical property that Dave
>mentions. Acrylic viewports in deep diving submersibles get polished and
>annealed on a regular schedule to combat hazing. Another pesky feature of
>Polycarbonate is its relatively poor chemical resistance, or propensity for
>stress cracking, which can have very unpleasant consequences in a pressure
>vessel. :-o Joe

It's the (cloading) hazing that I was worried about. I think I'd rather
just get much thicker acrylic to save the maintenance problems of
polycarbonate.

In fact I don't expect to go much deeper than about 30m, however I want to
test 
it to a deep as possible.

If this project is successful, then I'd be interested in one that can do
maybe 
200m.

Dave Everett.