I had painted it on 1/2" board. Maybe it's just me but I feel like if the board is too thin it needs a frame?
On a whim to get it hung I grabbed some cereal boxes and cut them into strips and began tacking them into the edge of the board. If I were to do it over I would probably paint the strips first and then add some glue around the edge before tacking it on.
You can see here I just used short black tacks.
Then I painted it with a copper metallic paint.
After it dried I took a little sand paper to roughen it up and give it a slight worn look.
And, wala. All done in about 20 minutes and a few pennies!