: I am building a yost sea rider,fist skin-on-frame. Is nylon the best
: covering,how strong is it compared to other materials? What would be the
: best weight nylon keeping it light but strong enough not to puncture or
: get damaged? Where can I buy some? even e-bay maybe?

You're building a wooden framed non-folder . . . correct? Typical skinning options include nylon, polyester, canvas and the PVC that Tom uses (Coverene, I believe). All have their good points and drawbacks - "best" is subjective, depending on how much work you want to put into skinning and the conditions you are expecting to paddle in.
As for weight, 8-12oz nylon or polyester is perfect. Look for #10 cotton duck if you go with canvas for some reason.
You can get nylon and polyester from the legendary George Dyson. He'll email you an informative list of his current stock. gdyson@gmail.com

More skinning info can be had by searching the www.qajaqusa.org forum or by perusing through some back issues of their newsletter, "the Masik." Good stuff.

Enjoy!
Dave