Hey Chief,
I've been using sheet PVC for stuff like that for years now. You can get a 4'x8'x3/4" sheet now for just under $100 bucks. A sheet goes a long way also. And you can buy regular old PVC cement (in the irrigation section of Home Depot) to mend. Just dont use the Purple primer
. Contact your local big lumber supplier. They'll have it.
If you're just going to make a cutting board, save money and time and buy a Magma Gunnel mount Cutting board.>>>
http://www.magmaproducts.com/Product...311_econo.html
I bought mine on ebay for $22 and LOVE it. It doesnt take any space on the boat and it drains bait/fish juice over the side. It cleans and stows easy. There are slots cut into it for holding your knife and pliers.
Worth the money.
Either way, good luck and post pics when you're done.