I've had no problem holding a magnet on its outside and bottom with glue. I've never seen glue used over the top. <div>
</div><div>I had a small neodymium (very strong!) magnet on a foam plane and had the foam around it pull away with the magnet.  I then put in some lite ply to hold the magnet. The magnet is a very snug fit in the ply. Ditto on a ferrous screw to mate it with, works great. When I glue in the magnet, I place a small piece of saran wrap or other thin plastic film between the magnet and its mate. This keeps the glue off things, and creates a small gap which maximizes the holding power. </div>