I've received a ton of emails and I decided to post the details here.  I used the Step Flash to make the Magnetic Boards.

I purchased the Step Flash at Lowe's in the roofing department.  Here's a picture.  It's galvanized and it comes in the 5 x7 size.  I bought it myself and I can walk you right to it. 

Step flashi

My advice is to go to the store yourself.  If you call them more than likely you will encounter someone that doesn't know. I went to Lowes and Home Depot twice…..I was looking in the AC dept but they're in the roofing department and I only found them at Lowes. 

Good luck!

p.s. I'm not supposed to post other store names on my blog….but I continue to receive a ton of emails. Hopefully this will clear up any confusion.