Not magnetic.

Yesterday, I purchased a magnetic surface primer.

It was disastrous from the beginning. First, I opened it too close to some of the boards I removed the masking film from. It splattered over them and kind of ruined 3 of them. Which means more spray paint work.

 

I continued by experimenting with the primer on MDF with layers of blackboard over it.

Sadly, the oily nature of it seems to mess with the effectiveness of the blackboard paint. As a result, chalk used on the board does not come off very well. It also seems to prevent the blackboard paint from staying on the surface, it comes off when I wiped the chalk.

The magnet primer has a very weak pull on the magnet I tested. 

It was a valuable thing to experiment with , and I'm glad I tested the amazing possibility of a magnetic blackboard. But I believe that it reduces the effectiveness of the blackboard in favour if a minimal magnetic feature. So I am now, more than ever, convinced I should stickto 'plain' blackboards.