Our refrigerator door is cluttered with all the usual papers and pictures of various and sundry sources. To hold all that up, the door is plagued by the litter of lousy magnets that barely win out over the inexorable pull of gravity.
I bought a selection of neodymium magnets in sizes that fit Lego plates and bricks.
- For the 1xN plates, I bought some 3/16"x3/16"x1/16" N42 square magnets.
- For the 2xN plates, I bought some 3/16"x1/16" N42 disc magnets.
- For the 1xN bricks, I bought some 3/16" N42 cube magnets.
- For the 2xN bricks, I bought some 3/16"x1/4" N42 cylinder magnets.
Gluing a single magnet into the base of a Lego piece can be tricky. You must work with a single magnet at a time, or they have a tendency to jump to each other, making the glue you just put on them go places you don't want it to. I found that to keep the glued pieces from jumping to each other and making a gooey mess, I needed to build a frame that I could connect the glued pieces to. That allowed me to work on gluing more magnets while the others dried.
Since the void inside the Lego piece is deeper than the magnet by a little bit, you need to make sure the magnet is flush with the bottom of the Lego piece. You can do that by setting the magnet on the work surface, applying glue to it, and then carefully placing the Lego piece over it. And since you don't want to glue these things to your counter, you need to do all of this on a piece of wax paper.
Another pitfall to avoid is applying glue around all sides of the magnet. When gluing a 1x1 brick, I found that air was trapped behind the magnet, so I would press the magnet into the brick and the air would push it half way out again. Applying glue to the magnet so that one side isn't glued allows that air to escape so you don't have to fight Boyle's law.
The result was surprisingly strong. The plates can hold photos easily, and the bricks are a lot stronger than that. A single magnet in a plate holds a lego mosaic made of a couple dozen parts to the refrigerator quite easily.
And now colorful Lego pieces cling tenaciously to the refrigerator.