Here's another thought.

Picture the profile of the tub you want.
Cut this profile into a ply rib, and repeat every 6 inches or so.
Then cut a profile of the tub at rt angles to the first every 6
inches, with slots to fit in the other ribs.
2 inches depth would be stupendously strong, with an upper and lower
glass skin.

Brian Whatcott

On 18 Oct 2005 15:39:52 -0700, wrote:

Hi,

A number of weeks ago, I posted a question on this group about building
a composite hot tub by "borrowing" some boatbuilding methods. I've been
looking at cold-molding vs sheathed strip (is this synonymous with wood
cored glass?).

If I used sheathed strip (with 1/4"-1/2" or greater core), I might not
be able to obtain the desired curvature. I could probably obtain the
desired shape with cold-molding using veneers, but I think I that I
would have to make a decent mold to support the veneers during
construction, and it would still be awkward.

I read some posts about people using multiple layers of thin wood
strips for cold molding, instead of using veneers. I'm going to have
some exterior framing surrounding the tub, and I think that I could
simply attach the first layer of wood strips directly to this frame
(probably via staples). Then add a second layer of strips, diagonally
oriented from the first, working from the inside. Then a third diagonal
layer, with the opposite orientation. The strips would probably be 1/8"
each. I'm not sure exactly how many layers I would use, I would gauge
the stiffness of the structure after 3 layers and go from there.

My question is this: If you are planning on using this type of "cold
molding", and plan on encasing everything in glass in the end, what
type of glue/epoxy can you get away with for the layers of wood in
between? I've read that a lot of the sheathed strip kayak builders get
away with using yellow wood glue (some even say they've used hot glue),
knowing that the fiberglass is going to provide a moisture barrier.
Keep in mind that I would be edge gluing the strips together, and also
gluing each layer to the previous one.

Thanks for the help.

Shamus