3/4 MDF *
1/2 MDF *
24" Tight-Seal Strip Brushes McMaster item# 74405T14 for 3" steel backing (other sizes available in the same section)
1/2" Neodymium Magnets (available on amazon or ebay) *
1/4 - 20 hardware
* substitute with what you have around the shop. Make adjustments to .dxf as necessary.