I am preparing to make a replacement companionway hatch for a Hinterhoeller HR25. The original was half inch plywood with thin teak decking on top. Overall size is about 30 inches wide by about 45 inches fore and aft. I expect to laminate 4 layers of eighth inch plywood with epoxy to reproduce the main structure, and then decide whether to attempt recovering the old teak decking, etc.

My question is about jigging and clamping. I was thinking that the following would work:

1. Determine the set-up camber, so that the finished unit is about the same as the original after spring-back.

2. Make a male form from three eighths plywood, propped with a piece of 2-by stock in the center to get the right camber, and cover it with poly for a release film.

3. Fasten the first eighth inch ply over the jig on each edge with a batten and screws, and roll on the epoxy.

4. Wet out the underside of the second ply.

5. Lay down the second ply and fasten on one edge, then roll it out to reduce air pockets, and fasten the other edge.

6. Continue for the rest of the plies.

7. Lay down a poly-covered three eighths plywood top to the jig and clamp the entire unit on each edge, then allow the epoxy to set.

Will this technique work out OK, or will I experience a lot of voids, etc? Do you have a preferred method? I was thinking of alternating grain directions, and possibly laying the center two plies on the bias, at about 45 degrees to the top and bottom plies, yet at right angles to each other.

Thoughts? Do you recommend any particular epoxy (west, east, etc.)? Will I need athwartships bracing across the top and bottom jig panels to get enough uniform compression?

Paul Van Voorhees
Buffalo, NY
p.van.v@netzero.net