Board
Step 1. Cut a 12" x 12" square out of foamboard and paint it black. I didn't cut it with my Cricut by the way, it's just where I photographed it.
Step 2. Glue on galvanized tin step flashing. I used several sheets. I didn't go all the way to the edges because I wanted to make sure the paper was attached to the foam board around the edge.
The leftovers are very useful, so don't throw them out. None of my local hardware stores sold this, so I had to order it online. If you are shopping locally, it's helpful to carry a magnet with you to test for magenetism. Just don't carry it next to your credit cards, or other things that are affected :D.
Step 3. Glue on the Chalk Paper.
Magnetic Photo Corners
Step 1. Cut cardstock into 2 1.5" x 1.5" squares.
Step 2. Fold in half as shown.
Step. 3. Fold in half in the other direction.
Step 4. Open and apply glue in 1 quarter of the square and fold in half. If you glue more than a quarter, there won't be a pocket to stick the sign in.
Step 5. Apply glue to 1 quarter of the square. Attach magnet to back.
Supplies:
American Crafts Chalk Paper
ProMag Magnets
Galvanized Tin Step Flashing (used for roofing, but don't get the aluminium that is also used).
Foam Board Black Acrylic Paint