Hi Hank (and Mike)

> My mold worked because the stiff mortar mix that I used for my seat had
> enough body that I could form it inside the frame and it didn't slump.

Since I don't have any easy access to foam, but a lot of access to concrete and grout (work at precast concrete manufacturer), I think I'll try Hank's original idea of the box with grout or mud inside it. I'll make the original impression and "dress it up" a bit with plaster and then make a female mold off that.

I'm not too concerned with fitting the bottom of my boat at this point, so I think it's a workable solution.

> I would like to try carving a bit of foam, saturating it with plaster just
> to see if the foam could hold the weight of the plaster without deforming
> and/or if the viscosity of the plaster was high enough that it would not
> ooze out of the foam before it set. This might be a quick & easy way
> to make patterns.

Hmm...I was thinking of carving the foam to make it as similar as possible to the shape of your posterior--this would keep it from distorting under your weight as little as possible. Then saturate it and sit in it in wetsuit covered with saran wrap...

> To answer your question directly, the cloth might work OK for fine details
> but the burlap, with the coarser weave would probably be better, stronger,
> more bulk - quicker. By all means - get a box of plaster and try it out.
> Let us know what you find out.

I have an existing carved minicell seat that fits well, but is too short. I could cover it and the cockpit with plastic, and then build up a mold that has more lumbar support and more under-thigh support.

> For our seat project you could build up a mold by stacking and packing
> plaster saturated bits of burlap to make a plaster frame inside a kayak,
> then add some plaster to the cavity and sit in it. Might be the hard way
> though.

My lovely wife is going to be gone every night next week....all that free time and nobody to complain while I make a mess with plaster!!!!! I'm gonna do it!

Shawn