I paint the signs for our nursery business and am having trouble knowing what wood to use. I have started using "Stop Rot" as the preservative base, followed by two coats of primer and then I do the color coat with sign paint I bought from Dick Blick art supplies. I do rather elaborate paintings with acrylic paints sealed with a sign varnish. The question is: What is the best wood to use and is it possible to use glued (attached? compressed?) board to make a sign -say 2.5x3' or larger? I see large painted signs on business' everywhere, but I have no idea where they are getting the panels. I have tried Lowes and Home Depot and no one there seems to understand the problem. They suggested compressed board, but I am afraid that will just rot and peel in a short time. Any secrets you can share? Thanks.