I find an easy way out. I can simply place the metal plate above the
inner skin of the cored deck, add two layers of fiberglass cloth over
the metal plate, and then place the thickened epoxy and the outer skin
over it -- kind of encapsulating the metal plate inside the deck. Then
I don't need to cut open the inner skin.

Jay Chan

wrote:
Oh boy, just when I thought I can safely use the toggle bolt to secure
the bench on my boat...

Seem like I will have to somehow mount a metal plate underneath the
deck with a pre-drilled hole for each toggle bolt in order to spread
the load. This will mean that I need to cut open the inner skin of the
cored deck in order to insert that metal plate.

The other alternative was to weld the nuts on the metal plate before I
put the metal plate under the deck. But this would be very tricky to
line up the welded nuts if the metal plate with the mounting holes of
the bench seat. I guess I am better off using the toggle bolts but
with metal-plate and epoxy re-inforcement.

Oh well... This is getting more tricky than I thought.

Jay Chan


dog wrote:
The real problem I see with the toggle bolts you show is they appear to
spread the load out onto the two edges of the plate that ends up under
the deck. This is not a flat bearing surface, and concentrates the load
on two relatively thin edges. This is not a good idea on a laminate
surface, as it will easily crush the laminate, even if you've
reinforced it with thickened, high-density filler, epoxy.

The load really needs to be spread out over a large surface area when
working with laminates. The toggle bolts can't do thisÑthe concentrate
the loading stresses onto an area smaller than that of a proper backing
washer...