Meredith asked about my tiles.
For the ones I had posted I mounted those on the pre stretched canvases that the Arts Council provided. I ripped the canvas off though and just used the backer boards. I used an industrial cement to glue them to the frame. Also I painted the frames with black gesso so they would look nice on the edges.
This picture shows the backside of the canvas with the canvas still attached.
Here is the link for the canvases the AC ordered. They run about 2.19 each. I don't know if it's worth it to do this way or just cut a notch in a thicker tile back. I do like having the boards but hate to have to rip the canvas off. I'll use it for something else I guess.