Things You'll Need
Instructions
Remove the backing from the photo frame that you want to use. Use this as a template to cut your Plexiglas to the proper size.
Lay the back of the photo frame onto your Plexiglas sheet. Using your marker, trace a line around the backing directly onto the Plexiglas.
Place your straight edge on the line that you marked. Using a sharp scribe or knife, drag the blade against the straight edge several times to score the Plexiglas. Be sure to cut on the inside of the line you marked, in order to make sure the line does not show up on your photo frame.
Clamp the section of Plexiglas to a table with the score line aligned on the edge of the table. Push down on the Plexiglas section that is hanging over the edge to separate the section. If you have a saw available, you may also use this to cut out the shape you need.
Remove the rough edges by running a file or sandpaper over the edges of the Plexiglas. Place the Plexiglas into the photo frame and reinstall the backing.