Most of the stores, from what I am told sell screens for finding teeth. I made mine about 10" x 12". Used 1/4 inch screen on a frame made with 1 x 2's. Wood is 99¢ (1 x 2 x 8), a couple nails to make the frame and a staple gun to put the screen on. Worked great, sturdy enough to handle wet sand, yet light enough for the kids to use.
