My daughter bought a very nice stone mosaic or her trip to Jordan. It has a net back, like mosaic bathroom tile at Home Depot, and should be mounted on a backer board, then hung on a wall.
She wants to hang it on her front porch, outside, but not where it will get wet, and just a little Sun. It is about 20X24", and reasonably heavy, so I want to glue it to a strong, flat surface to hang. It will also have trim around the edges to encapsulate the small stone pieces, and hide the ply edges.
Is the glue used in BB going to hold up for dry, but still exterior use? Most exterior plywood I have is not really that flat, and this will be a one shot deal, as I don't think the mosaic could ever be removed intact.
My other choice is particle board, but that just doesn't seem right.
I also considered tile backer over the ply, but that will make it even heavier to hang, so leaning against it.
Any thoughts?