How to make a giant chalkboard! :)

Step 1: Materials

There isn't much required.

48 x 48 piece of 5/8" plywood
48 x 48 sheet of 24 ga. sheet metal
Liquid Nails
Chalkboard paint
Base board
Wood screws
Finish Nails

Step 2: Plywood base

Then trim the board to 45 X 45 so that there will be a 1.5" border of exposed plywood on the edge. You then use liquid nails to secure the sheet metal to the plywood. You don't need sheet metal, this just makes the chalk board magnetic. 

Step 3: Poof! Chalkboard.

After the liquid nails set you paint the metal with some Glidden chalkboard paint from the hardware store.  This paint is the most expensive part of the project.  It is about $15.00 per pint.  It is important that you follow the drying and curing instructions on the can.  If you try to rush the paint it wont give you the nice smooth surface you need.  Also, you should use a dense foam roller rather than a brush.