Art Todesco wrote:
I have some corrugated cardboard halloween decorations that I would like
to put out on the lawn. Last year, when they got a little wet, they
curled and "melted" a bit. BTW, las Halloween was constant rain. Does
anyone know of a way to waterproof the cardboard? The surface is black
colored paper. Interrnally, it is like any other corrugated cardboard.

There is a plastic version - formed like corrugated, but all plastic. I
would check craft stores for a more suitable surface. There is also a
painting ground, for oil or acryllic, made like masonite but with a
"primer" on it. Probably would only have to waterproof the edge, if
anything. I can't imagine anything that would reliably coat the inside
and outside of corrugated cardboard.