Here is some facts and tips about magnetic chalkboard paint that might be usefull for your project ;
Chalkboard Paint Details
Chalkboards aren’t just for schoolrooms anymore—chalkboard paint makes it easy to create writeable surfaces all over your home. Most chalkboard paint can be used on metal, wood, masonry, plaster, glass and concrete.
Tip for Applying: Allow your chalkboard painted area or item to dry for 3 days. Once dry, prepare the surface for use by rubbing a side of chalk over the entire surface, and then erasing it thoroughly.
Magnetic Primer Facts
Magnetic Primer typically comes as a dark grey or black base coat and allows you to create a magnetic surface just about anywhere you please. It can be used on all of the same surfaces as chalkboard paint and can be used as a base under chalkboard paint or any latex paint. Once finished, hang notes, lists, photographs and more.
Tip for Applying and Usage: Magnetic primer is not quite as strong as your typical magnetic surface, so make sure to apply 2-3 coats of the primer and just 2 topcoats for the best attraction. Look for flat, lightweight magnets with strong attraction for posting your items on your magnetic area.
( Magnetic Chalkboard Paint )