wrote in message
ups.com...
Leaving the frames out would be good - otherwise I'd have to put a
layer of wood on the inside too (for comfort reasons - it is a hot
tub).

Don't know if anyone has mention this before, but as I understand epoxies
are highly sensitive to temperature. This was googled out on "epoxy
temperature" search:
http://www.epoxyproducts.com/novolac.html

I anticipate the tub being about 104 degrees F. So notwithstanding any
problems with my heat source, I should be below the 140-160 degree
maximum (for wet conditions) of regular epoxy. Although my heat source
is wood-fired, I have a thermostat of sorts worked out. I can probably
control the temperature to within a few degrees.