Here's our solution for lumbar seat inserts that follow CPM slope. We made
them out of foam and balsa. The Factory rear seat cushion needed to be
raised 1" so the Velcro on it was aligned with the headrest, so we
incorporated a 1" piece of foam with the insert.
We cut the insert by marking the foam and using Rapid Epoxy to stick on a
piece of 1"x2" as a guide for the saw. A Carpenter's wood saw works, but
we liked better using a power hacksaw blade laying around. No matter have
one person on each side, sawing goes fast.
We have another concern, that is when air-brake cables get installed, the
insert needs to accommodate. We put 1/4" balsa on the front of the insert
which will allow us to cut foam for air-brake cables, and the 1/4" balsa
has enough strength on its own to keep the insert together. The rest of
the Balsa is 1/8".
The large part of the insert is made from Aircraft Spruce Polystyrene
Large Cell Foam, the 1" bottom laminate is Styrofoam Small Cell.
Ron Parigoris
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