Test tube racks are a lab staple. By stabilizing tubes, they make it easier to pour, pipette, mix, and observe reactions. They also help keep tubes (and thus experiments) well organized. However, if you’re experimenting from a new location this fall you might not have access to any.
Luckily sturdy substitutes are easy to make! Whether you’re working on your own basement or backyard breakthrough this fall or planning to use one of our MyLab distance learning experiments, consider spending a few minutes making your own DIY test tube rack. Here are four quick and easy ones that were used by Edvotek staff this summer and come highly recommended.
Tinfoil + Small box + Rubber band:
Stretch the tin foil over a box or small container and then secure it with a rubber band. Next, gently poke your test tubes through. Sometimes I’ve found that starting the holes with a pencil keeps them from ripping and getting too big (the main Achilles heel of this rack). A major pro of this method is that it also works great for heating tubes in hot water or in a water bath.
Cardboard + Small box + Duct tape:
Switching out the tinfoil for a thin piece of cardboard takes a little more time but makes for a sturdier and reusable option. First draw the holes and then cut them out with a sharp blade or by folding the paper and using scissors. If you plan on using microcentrifuge tubes the diameter of each hole should be ~10 mm. For larger 15 mL or 50 mL tubes the diameter should be closer to 15 mm or 30 mm respectively.
Play-dough / Modeling clay:
Another great opinion is play-dough! This works with tubes of all sizes. If you don’t have play dough at home it is pretty easy to make it using flour, salt, cream of tartar, and water. There are many play-dough recipe online, here’s the link to the one I’ve used. Alternatively, this is the perfect excuse to order some. With this method you don’t need to measure or even know the tubes size before hand and it is easy to remake a new rack every time the experiment calls for different tubes. Another advantage is that play-dough doubles as a great fidget tool during those pesky incubation times!
Sand + Bowl:
Many labs use small metal beads (<1 cm diameter or less) to heat, cool and generally hold test tubes but these are expensive. Instead sand or similar small objects like pebbles can be used. This opinion is great for most experiments but should be avoided when you need to clean the lab space before and/or after the experiment such as when working with microbes or performing PCR.
Feeling a bit more ambitious? This YouTube video shows how to make a single but versatile test tube holder out of a Popsicle stick, thin binding wire, foam, and aluminum tape. Or, if you have a bit more time and some woodworking tools, you can make a colorful and professional quality wooden test tube rack after watchmaking this video guide. As always let us know how the building and experiments go.