[VAC] Re: More frame off stuff

[Dr. Gerald N. Johnson, electrical engineer]

Besides keeping the shear sheets separated the foam or balsa wood or
honeycomb has to keep the shear sheets from sliding relative to the core
and each other to develop bending stiffness to span the space between
"floor joists".

Might be something like a Formica layer on top contact cemented (there
is a water based contact cement) to a layer of foam that had water pipe
channels and radiant heat water pipes embedded (standard contact cement
eats foam for lunch) and a 1/4" plywood or 1/16" aluminum bottom layer.
Pergo and others keep telling us (on the home shows) how great such a
pressure laminate is for flooring, why not make it structural? The water
pipe channels would probably want to run perpendicular to the floor
joists or spars so to maintain the bending strength of the sandwich. And
in a trailer would want to only be where the floor wasn't covered by
sofa or cabinet. Menards sells a fiberglass panel in 4x8' chunks as a
wall panel for dairy barns and the like. That might make both skins very
well and be a better insulator than aluminum.

If the upper surface is the finish floor, then there's a little more
room for insulation in the panel. The added thickness adds rigidity
also.

There is a structural adhesive (blue) for foam insulation. I tried a
sample of it sticking wood to foam (thinking about making my own foam
insulated doors for that house I'm hoping to build last decade) but I
found it wasn't very strong and the foam easily separated from the wood.
I've use contact cement (water based) to stick foam blocks together for
landscape modeling and it worked very well there. I don't have any at
the moment to test, but I do have a way to test for bending strength
when the temperature is well above zero (with -40 windchill). And could
compare such a composite to wood or plywood.

Gerald J.



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