Blue foam shouldn't be a problem

If you do go that route, remember that polyester resin will eat styrofoam (extruded polystyrene) so you'll have to use slightly more expensive epoxy resin. Look at http://www.raka.com for less-expensive, but very good resin.

I would think that two layers of 10-oz. cloth would be enough if you don't subject it to any big puncturing forces. Maybe 3 layers would be better.

Here's a link to a guy who built a surf kayak from a block of styrofoam, and then fiberglassed it: http://siolib-155.ucsd.edu/Preston/kayak/surfboat/

I like the way he built the "Gecko Boat". By glassing it first, and then hollowing out the cockpit, you wouldn't have to worry about breaking the thin shell, and you would also have a boat with great inherent floatation.

Good luck in your endeavor.

Shawn
> I am a Industrial design student who unfortunitly lives in the city. I
> have very limitted space to work in and I really want to try building my
> first kayak. I've been thinking of ways to build a kayak in a small area,
> with a small budget, in a big city, and with-out knowing much about kayaks
> other than they are great fun. I am currently working at a design firm as
> a modelmaker and my material of choice is blue-foam (rigid insulation) it
> is easy to carve and sand. It is light weight and floats very well. I was
> wondering just how thick of a layer ofd fiberglass is needed. I thought
> that maybe I can sculpt my kayak out of the foam and then coat it in
> fiberglass. The only thing that is questionable is if I go through all
> this trouble of carving this monster model am I going to coat it and sand,
> and paint and then when I put it in the water get all excited because it
> floats and then i go to sit in it and fall right through the bottum? I
> need structure advice/ideas and an answer to my fiberglass question.
> please e-mail me because I had to beg for computer time and unless I get
> an e-mail I'm sure that they will not let me have access to the
> computer.thank you