Cool Stuff for Mosaic Artists
Skeewbacker Ultra Classics - Mosaic Backers
Skeewbacker Ultra Classics are becoming the standard in mosaic backers. All things considered they cost about the same as plywood, but are infinitely better because they are easier to work with, super lightweight, and waterproof. They are constructed with a layer of polystyrene sandwiched between two waterproof barriers. You can choose 1/4" or 1/2" thicknesses. 25 sizes to choose from and many are standard frame sizes.
See this How it Works video.
ONE-QUARTER INCH THICKNESS