In uk.d-i-y Guy King wrote:
The message
from "Fray Bentos" contains these words:
I have been thinking about this for a while now.
I have a large dg window. about 8ft by 5ft.
Just how easy is it to drill a small hole in the opposing diagonal corners
and let it dry out in sumer then put a small bung of silicon in the holes to
seal again ?
Depends for one thing whether it's toughened or not. If it is, you ain't
a hope of drilling a hole.
There is, it's relatively easy, you just first anneal the pane

This is pretty tricky - you've got to keep pretty good temperature
control (+-10C IIRC), ramp it up and down slowly, not to mention not
having any dust in there.
But then, think of all the other handy jobs you could find for an
annealing furnace.