Your choice of base and binder depend on the size of your mosaic and its final location (indoor/outdoor). A variety of supports may be used, but regardless of the type chosen, the surface should always be "roughened" to improve adhesion. MARINE PLYWOOD To "key" the binder onto the surface first you have to provide a rough surface by gluing sand or fine gravel on your base. A normal white glue may be used. To prevent warping, marine plywood should be used in thicknesses of 1/4 inch or greater. METAL and MARBLE Use an epoxy resin to glue sand or fine gravel on your base before spreading the binder. AEROLAM and HEXLITE For large mosaics it is best to use a particular type of support called AEROLAM or HEXLITE. This panel is made of two sheets of resin with an aluminum honeycomb core. It is excellent for large mosaics because it does not warp or crack and it is very light. CONCRETE/CONCRETEBOARD For any outside mosaic, especially a floor mosaic, we recommend using either a Concrete or Concreteboard foundation. Concreteboard is available at many home improvement stores.