Made some custom frames for the 8.5 x 11" certificates for a couple of people who were made honorary members of my Masonic Lodge. Got to use my new big 50W laser
Made from 3 layers of 1/8" birch ply, stained and unstained. Gloss lacquer finish on all layers. The back layer was smaller on the inside cut by 3mm on each side, relative to the mat (middle) layer, to give the recess for the glass, certificate and backing board.
Used 0.08" (~2mm) acrylic sheet as the glass and 30pt (~0.77mm) chipboard as the backing. Added some turn buttons to the back to hold the contents in place.