Mark IV sun visors

I have the shape and hardware for my sun visors, but I do not know what kind of cardboard is inside or what trim, if any, is sewn around the edge.
Regards,
Denis

Here is what my '38 SS has. It feels like 1/8" plywood, with just cloth glued on both sides. One side was oversize with the edges folded over around, then the other side glued over it.

Rob’s description is the the same as on my '48. It is a simple one piece fabric glued and folded over the panel. The trick is to make the closing seams ‘invisible’.

Make new bases from 3mm marine ply, no thicker. The fibreboard types like millboard warp and buckle too easily. Round off all edges to create a semicircular profile. Drill the holes for the hinge screws in positions such that the board is against the shoulder of the hinge.

Use the same material as the head lining and don’t add padding. Cut to the shape of the ply, double width for a full fold over, with about 1cm extra all round.

No stitching is required and a smooth all-over finish is achieved with an almost invisible seam.
I copied my original and quizzed a motor trimmer about the method of attachment, which confirmed my assumptions. The seam is in the centre of the edges on three sides.

Spray contact adhesive on both sides and all edges of the ply, and the fabric. Carefully bring the trailing edge (ie, not the hinge edge) of the panel onto the centre of the fabric and roll down for face contact. Fold the other half of the fabric over for full face contact and press down firmly. The trick the trimmer told me for creating the seam is to ensure the fabric is a butt joint along the centre of the edges. The easiest way is to use both thumbs and extend the thumb nails over the edge to force the fabric down to glue. Both nails should meet together as this keeps the joint straight. This should be very thorough to ensure the fabric from both sides is tight together on the wood with no gap. When satisfied, trim the excess as close to the butt joint as possible and smooth down the joint.

It is surprisingly simple and satisfying when you achieve a neat finish.