I found myself needing to glue a boatload of equilateral triangles. They are made of long skinny double-layer thick Draftboard, for a total of 1/2” thick. I tried holding them together by hand but that just wasn’t cutting it. So I whipped up a gluing jig in Illustrator and it’s doing the job pretty well.
Made from 1/4” Draftboard and 1/8” Draftboard. The thicker piece is smaller and is sandwiched between two 1/8” pieces, to create a channel for the long rubber band.
If you’d like to make one for yourself, here’s the file; cut the blue lines out of 1/4” and the black lines out of 1/8”. And of course you will need an appropriately sized rubber band.