noseoil wrote:Welcome aboard! I used skeletonized plywood on mine, but ash would be good also. It's tougher & harder than plywood, but the weight would be an issue for me. Plywood is faster to build with, since it's a full size panel already. It can be hollowed out if you want some insulation in the walls.
You mentioned sealing the edges, but what will you be using for a covering? Is it going to be aluminum skins, paint, canvas & paint (PMF or poor man's fiberglass) or fiberglass & resin?
Since you're a wood worker, it should be fairly easy for you to make a good box, but I would still do a full scale mock-up of the build to get a handle on sizes (mattress, bulkheads, shelves, etc.) on some cardboard.
No covering--I might paint the top, but the sides will be stained and clear-coated. I might put some fiberglass, Steve Frederick style, on it. We'll see how exhausted I am by the end. I have also thought about some type of metal flashing for the wall-ceiling joint.
90 board feet of ash (both sides at 5x9) will weigh 360 pounds per the Lumber Weight Calculator. I think it will look amazing. A similar sized 3/4 plywood would weigh about 200 (70 pounds per 4x8 sheet). I really debated the skeletonized, stick, solid ply, solid lumber question. While this method will add a little weight, and I think an extra 160 pounds is acceptable, I think the main thing is I don't have to agonize about water penetration ruining my walls. I still want to keep the water out of course, but it's not a death sentence if it happens.