LEGO bricks with alphabet are weirdly unavailable in the 1x1 size. There are DUPLO bricks and small round pieces with letters, but each with only one letter. Doing it that way needs a pretty big bunch of bricks to actually be able to spell something.

Instead, I decided to make 1x1 bricks that have one letter on each side. This way needs only one quarter the size of inventory of bricks on average. I bought a lot of 250 pieces 1x1 white bricks from eBay seller stein-experte. Now I just need to add the text.

Engraving

To engrave the bricks, I used the K40 laser cutter at my local hackerspace. The settings were 1000 mm/min speed and the smallest power the tube would run at.

An aligment guide made it easy to place a stack of 10 bricks for engraving. I would then incrementally rotate each stack and move it forwards to engrave each side.

Inking

The CO2 laser just melts the ABS and does not give much contrast in the markings. To make them more visible, I used a pen to color in the grooves. Excess ink can then be wiped out, leaving a well-defined letter.

Initially I tried an alcohol-based permanent marker. Unfortunately the alcohol caused tiny cracks in the ABS plastic, and the ink seeped into them. A water-based gel ballpoint pen worked much better, and after drying the marking seems durable enough.

Files

The Inkscape drawing of the DIY letter template is available here.