Lobster wrote:

Yes, the stuff cuts fine using score'n snap; it's obviously just
ordinary glass.

excellent news, thanks


(You then run down a Stanley knife down the back to cut
the reinforcing film, like cutting plasterboard).

I've been doing enough of that lately, reminds me to buy *more* Stanley
blades ...

How does a DIY'er achieve the ground edges to a glass pane that you get
on commercially-supplied mirrors? Grinding wheel in an angle grinder
shudder ?

Shudder indeed, my thought was a carborundum stone applied by hand,
google seems to show that is what amateur telescope makers use on their
mirrors/lenses.

http://www.stellafane.com/atm/atm_grind/atm_bevel.htm