Hardboard is made from fine wood rather than wood particles and can be used as a mounting board or as panels for flexible canvases. Others prefer to use the hardboard as a painting surface. Tempered hardboard is pretreated with an oil to make it more resistant to water, and it is flexible yet strong. When an artist completes a work on tempered hardboard, he must still mount the board to a backing in order to properly frame or place it.
When your hardwood project is completely dry, seal the hardboard using a non-yellowing acrylic finish to minimize fading and decomposition of the wood. Allow the acrylic to dry for about 48 hours.
Dampen the backside of the hardboard as well as the the mounting medium. Applying a generous amount of wood glue to both surfaces and place the hardboard on the backing.
Clamp the hardboard to the mounting surface, making sure to clean up any excess glue as the two pieces are connected and held in place with the clamps. Allow the glue to dry completely before removing the clamps. Trim the mounting surface if needed.