I need to make a cover for a fry-pan, with a glass window. I have a
"universal" cover, but it doesn't work well. In fact I've been using
a double layer of tin foil that works just as well.

I recently bought a set of fry-pans, moderately expensive, not the
cheap stuff I usually get.

The mediums sized pan has a cover, a glass cover, but the little one I
use more has nothin'. And there are few if any 8" pans for sale with
covers.

I figured I'd make one out of wood and glass. Maybe I'll rout a
little ledge for the glass to sit on, or I'll use some sort of molding
on top. Maybe I'll also glue it on with PC-7 or JB weld .

Any reason not to use plywood? The glue won't drip into my food, will
it?

What kind of glass do you think I need? I presume window glass will
break, if it gets even moderately unevenly hot, or if I hit it
accidentally. . I have a piece of thicker glass from a flat-bed
computer scanner. And somewhere I have a much thicker piece of glass
from a Royal photocopier, about 35 years old. I gather it's hard to
cut old glass -- and this thick would be even harder??

How hard would it be to cut it in a circle. If necessary I can use a
square, or a hexagon.

Thanks.