The lab needed to run an algae test using several Erlenmeyer flasks on an orbital shaker. The flasks had to remain exposed to light, but they would wobble and fall from the shaker platform during operation.

The original idea was to build some kind of fixture that would clamp onto the shaker and hold the flasks.  That would have worked, but it also would have required more parts, more adjustment, and a fairly elaborate mounting system.

I tried to focus on solving the problem in a simpler way.  The flasks didn’t really need to be clamped in place. They just needed something to keep them from falling off.

I decided to make a box out of acrylic sheet.  I first made a heavy paper version to check the dimensions, flask clearance, and overall height. Once the layout looked right, I used the paper pieces as templates, ordered cut-to-size plastic, and built the final enclosure from clear acrylic.  For the holes, I made a template out of MDF board, then clamped the acrylic to the MDF and used a router with a laminate trim bit to follow the template holes and cut a smooth edge on the acrylic.  

The finished guard fits within the edges of the shaker platform, with holes for the flask necks at the top. The acrylic allows light to reach the algae cultures while the walls contain any flask that begins to wander or tip. It’s a simple removable box, and is easy to lift off for cleaning or for other shaker setups.