Maximizing Strength of Refrigerator Door Magnets

[m iket]

I think this belongs here because its about magnets, except for the adhesive part which may be materials.

Im improving my refrigerator door magnets that constantly get knocked off or shift around all the time.

1. What thickness of neodymium magnet will saturate a refrigerator door?? For instance I have a 1/32" magnet but with a layer of 5mil latex glove and the paint between them its significantly weaker than my larger neodymium magnets to the door.

2. Will a piece of thick sheet metal on the backside of a thin but wide magnet provide most of the advantage of a cup?? Are there commercial sources for thin cups? I'll probably use 3/4" or 1" wide neodymiums.

3 What adhesive would be good for gluing latex rubber to a shiny magnet?? The friction from the rubber makes it much harder to slide around than a smooth magnet. I tried 3m 77 spray adhesive but it pulled off the magnet when sliding it around.

Are there any simple equations or rules of thumb regarding magnet thickness or strength? I tried but couldn't find the information i was looking for.

 

[MagnetDave]

I think this belongs here because its about magnets, except for the adhesive part which may be materials.

Im improving my refrigerator door magnets that constantly get knocked off or shift around all the time.

1. What thickness of neodymium magnet will saturate a refrigerator door?? For instance I have a 1/32" magnet but with a layer of 5mil latex glove and the paint between them its significantly weaker than my larger neodymium magnets to the door.

More less any useful size of neodymium will saturate the metal under it on a refrigerator door.

2. Will a piece of thick sheet metal on the backside of a thin but wide magnet provide most of the advantage of a cup?? Are there commercial sources for thin cups? I'll probably use 3/4" or 1" wide neodymiums.

No. You really need to "close the circuit" of magnetic field.

3 What adhesive would be good for gluing latex rubber to a shiny magnet?? The friction from the rubber makes it much harder to slide around than a smooth magnet. I tried 3m 77 spray adhesive but it pulled off the magnet when sliding it around.

Shiny magnet are lousy to glue to with any adhesive. Recommend you rough the magnet surface first with sandblast (or sandpaper, in a pinch). Loctite as a number of adhesives they designate as "magnet bonders" that work pretty well. Most epoxies are fairly good, also.

Are there any simple equations or rules of thumb regarding magnet thickness or strength? I tried but couldn't find the information i was looking for.

http://www.arnoldmagnetics.com/Content1.aspx?id=4621

Or you can download Arnold's iPhone app.