I’m just getting up and running with my machine, and made this for a chemist friend’s upcoming birthday. It’s all proofgrade, and you could mix up the materials as you wish (but keep the middle layer of the holder thick). Next time I might use veneer for the outer layers and score the adhesive side to only expose where it needs to attach.
Test tubes: medium clear acrylic
Base: medium draftboard
Outer layers of holder: medium maple ply
Inner layer of holder: thick draftboard (mine measured at 0.22" with masking, so the base is designed for that measure)
testtubestand.svg.zip (4.7 KB)