MOM Tip: Make paper waterproof by adding silicone sealer.
1. Lay out the paper to be coated atop scrap newspaper.
2. Squeeze out a heavy line of silicone all the way across the top of the paper.
3. Using a scrap piece of cardboard, squeegee the silicone down the paper spreading a thin layer of silicone over the paper. Let the silicone dry.
This tip from Design Sponge.