Hi guys! I feel terrible about never getting back to this request. I am sorry. I attached the drawing of the frame, a friend helped me draw it. I can't draw. I made all the pieces from 3/4 walnut. I added straight pieces in the centers to increase the width and length. For strength I put a dowel in every joint. Not necessary if you glue your backer in. I made a rabit joint around the back inside edge for my backer. Feel free to take a copy of it. You can play with the size of it when you print it out.
\Any problems just send me a note. I promise I'll get right back to you