Evan, i've thought that the 'puck' that's in place of the core under a
loaded fastening only needs to have the compression strength to bear the
fastening loads and be non-decaying. In that case, most any high-strength
bog will do the job. Why glass?


wrote in message
ups.com...
Evan Gatehouse wrote:
wrote:
Jim Conlin wrote:

Noah's Marine has half-sheets of core-cell at good prices. They can
ship.
It's perfectly OK to piece it together.
The function of the core is to keep the skins a constant diatance
apart and
to bear shear loads. Cored panels as they are thicker in section are
stiffer
than solid glass panels. Foam cores need help in this only where
there are
heavy compression loads, as from fastenings.
The drawback of plywood core is that when water gets to it, it'll rot.
And
it's heavy.


Thanks for the tip. In that case, I can ask the vendor to cut the
plain sheet in two or three pieces in order for UPS to ship. The
other
option is buying scored sheets that are small in size and can be
shipped.

If I understand you correctly, a solid fiberglass panel should be
great
for the T-top to anchor on as long as it is as thick as a cored panel.
Of course, I will not make the whole deck in solid fiberglass; that
would be too heavy. I will use solid fiberglass in the small areas
where the T-top is anchored on.

Jay Chan

Solid fiberglass is a good option for through bolting hardware. But
you don't need the solid glass to be thick as the core unless you can
only get to the top side of the sole. If you can get to the bottom,
you can taper the core out to nothing and make the solid glass about =
3/4 the bolt diameter. For a cockpit sole, where you might not be
able to get to the back side, then a solid glass laminate will have
to be the same thickness as the core. Just slightly larger than the
footprint of the mounting base is enough.

Evan Gatehouse

Thanks. I will keep the formula (glass-thickness = 3/4 bolt diameter)
in mind. This will come in handy.

I have very little (or no) access to the back side of the deck where
the T-top footing is. Sound like I will need to make the solid
fiberglass as thick as the deck.

Good to know that the fiberglass bedding area only need to be slightly
larger than the footprint of the T-top mounting base. This settles the
issue. Thanks.

Jay Chan