Whether you're gluing wood to a mirror's surface to frame the mirror, create a decorative pattern, add paneling over the mirror's face or for some other purpose, the process is similar. A mirror's silvering is attached to the back of the mirror, beneath the mirror's glass. Because the silvering is projected by the glass, special mirror glue such as mirror mastic is unnecessary if you're gluing wood to the front of the mirror. All you need is strong, clear epoxy glue.
Squeeze the epoxy out of the tube and apply it to the back of the wood.
Affix the epoxy-covered backside of the wood to the mirror's surface.
Hold the wood in place and affix a strip of painter's tape over the wood piece to keep the wood from drifting while the epoxy dries. Attach the tape to the mirror, then over the wood piece, and back onto the mirror. Allow the epoxy to dry according to the directions on the packaging.
Remove the painter's tape.