What could be the reason for magnets not adhering to the material?
One reason could be that the magnetic primer is not thick enough. You should apply at least 3-4 layers in a crosswise manner. You should also use strong magnets.MAGNET paint application
How do I apply Marabu MAGNET to the surface?
The magnetic base paint should be stirred well before use. Apply several coats (at least 3-4) of Marabu MAGNET undiluted and with crosswise brush strokes.Yield of MAGNET
How big an area can I cover with Marabu MAGNET?
Marabu MAGNET 250 ml will cover an area of approximately 2 m² (depending on thickness).