Everyone know the foil lids are the undisputed lab champs for normal use and storage. What many people don’t know is that they are more than $2 each! Also, sometimes we can be out and they can be on backorder. Luckily, we have more than 1000 other lids on hand. The problem is that some have bad reputations. Lets find out if they are earned or not!

TLDR: Use Fisherbrand, seal with 75C lid temp.

Materials:

In this potato quality photo we see the 4 contenders. All are labeled (or assumed) to be some type of thermo-sensitive heat sealing lid.

Method:
Put H20 in a bunch of plates seal them (5 minutes @65C, the lid temp was ~75C*) and see what happens! I measured the corners and random wells to see if there was any loss.

Results:
1) BioRad Microseal. Lab annotation: “I SUCK”. Myth confirmed! This is like a big sheet of parafilm that is impossible to get stuck to your plate. When I opened the thermocycler it was stuck to the thermocycler lid. Do not recommend.

2) Fisherbrand Thermal adhesive sealing film The best of the batch. It peals off fairly easily although it is nice and sticky. No loss. No spills. Appears to do okay in the freezer although I did not do a very long term test.

3) AB Microamp Lab annotation: “Worthless”. An indeed it is! This survived a few tests but some wells seal better than others. It failed the being dropped upside down from about 6 inches, a few of the wells spilled into each other. Do not recommend.

4) I work for short term Lab annotation: “I SUCK”. After the first simple test this appeared to be about the same as #2 with okay performance. I did not test it as much as the others.

*Bonus discovery: I set all the bays on the white thermocycler to 25C and the lid temp only got to 30C for all but #1 which was at 60C. At other temperatures they all acted the same.