Good point about the metal will expand/contract more than the epoxy
will. I didn't think of that. But I can easily avoid this problem by
leaving the metal plate kind of free floating by only sticking the
middle section of the metal plate with epoxy, and leaving the rest of
the metal plate free floating -- similarly to the way woodworker takes
care of wood expansion not to crack the joint.

As of epoxy doesn't bond well to the metal plate, this may not be a
problem if I intend the metal plate to be free floating anyway. Please
note that metal plate will be pressed against a new layer of fiberglass
not directly against the foam core. Basically, I use the metal plate
as somekind of a washer to distribute the load; therefore, it being
free floating should not be a problem.

As of the metal plate will have a hard edge against the laminate, I
think we can round the edge to minimize the problem. Thanks for
pointing this out. But this should not be a major issue considering
the fact that the metal plate is there to distribute the load;
therefore, the load gets to the edge of the metal plate should be
minimum (at least that is what I think).

As of this will tear a large part of the deck out, I really don't think
there is any mounting method can get around this if the force is so
great that it can tear out the deck. I don't worry about this.

Thanks for your reply though.

Jay Chan

dog wrote:
This is probably a really bad idea for several reasons.

1) The thermal expansion coefficient of metal is far greater than that
of foam, wood or fiberglass. The heating and cooling cycles will cause
stress cracks and delamination.
2) The metal plate will cause hard edges along the laminate, which
will be natural stress points and probably fracture the laminate along
them.
3) Prepping the metal to accept the epoxy can be a pain, and it may
not bond well enough to prevent a void.
4) installing the plate, and having the holes in the proper position
is difficult to do without introducing additional voids into the area
of laminate directly under the high load area.
5) If it fails, it will likely tear a section of deck away that is the
size of the metal plate or slightly larger. Fun Fun Fun.

But it is your choice.

On 2006-06-26 12:32:42 -0400, said:

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\