The tapes that suppliers sell in the recognition industry are sign tapes, mostly acrylic-based, that have high adhesion values. This is not the tape you buy in a paper supply store. Two 1/4-inch strips on the back of a plate is all you need for most projects. If you ever have to remove the plate you will appreciate a more minimal approach.
You can use more tape on rougher surfaces or if a plaque will be exposed to the sun through a window. If a sign is hung outdoors, for a solar installation, for example, use tape made specifically for the outdoors that has a higher heat value.
Acrylic tape increases its adherence value over several days following application. Taking a magnet off a name badge after an hour is much easier than after a week. This is something to remind customers that are concerned about how well the tape adheres.
-Bob Hagel, Eagle’s Mark