You can try this pouring technique on art canvases or 1/4" plywood. When pouring on a canvas, I always like to prep the canvas with a base coat of acrylic paint. When pouring on plywood, I always seal the wood with a coat of a latex primer to protect the wood from the water you'll mix with the acrylic.
This is the primed plywood I used over a drop cloth.
When doing a pour, raise the canvas or wood off the drop cloth or plastic a few inches to let the extra paint drip off the edges.