Magnetic Acrylic Coasters

I made some laser cut magnetic coasters for a 60th birthday present for a chemist friend. They're engraved with the information for element #60, gadolinium, probably most famous for its starring role in the strong rare earth magnets you find everywhere these days. To reinforce the chemistry vibe, they're hexagonal (a motif common in chemistry) and contain 6 "samples" of Gd, in the form of cylindrical magnets. They're arrayed around the outside edges, captured by laser cut recesses, and act to hold the coasters together nicely (to make a trivet of whatever size or shape you want).

1 sheet of 3 mm (1/8") clear plexiglass, 800 × 500 mm. Acrylic solvent. 50 pack of small rare-earth magnets. Access to a laser cutter. Some bulldog clips.

I made the design in Fusion, leaving 5 mm × 3 mm pockets for the magnets in two outline pieces (design available for editing). I transferred the Gd label from my Periodic Coasters instructable to this one, resizing it so fitted nicely inside the outline of the inner hexagon. I did the assembly inside CorelDraw, but any drawing program would work for this.

Note the extra engraving on the cutouts inside the outlines - I did this to make regular coasters out of them so as not to waste any acrylic.

I set the laser cutter up to cut the red lines at 100% power and 1% speed, and to engrave the black at 100% power and 100% speed. It still took about an hour to cut. Engraving a big sheet is slow.

Peel off the stickers from both sides of the cut acrylic. Clip the base plate and the two outline pieces together using bulldog clips, and pop a magnet in each cavity, ensuring the polarity is alternated. Remove the clips while holding the pieces securely, pop on the top with your other hand, and realign and resecure with two bulldog clips.

Acrylic solvent is very runny, and will wick instantly in between the touching sheets. I used a small paintbrush to daub it on the edges, painting each edge while it was facing down so no streaks ran on to the faces. Very quick and easy if you take this precaution. Do it in a well-ventilated space. It dries almost instantly. You're done!