Cheap device for gel temp

Shiao Y. Wang sywang at
Thu Apr 28 23:41:38 EST 1994

I have designed a simple device that uses a normal lab thermometer to
measure the surface temp of a DNA sequencing gel. I found it to be
surprisingly useful and accurate. If you are interested in an
inexpensive device that measures the temp of a flat surface fairly
accurately, send me you mailing address and I'd be glad to send you a
drawing of how to make one.

It is basically a circular block of aluminum (diameter 5 cm by 1 cm
thick) that is insulated around the circumference and one flat side by
high density polyethylene. It has a hole drilled down into the aluminum in
which a ordinary lab thermometer fits snugly. (Thing looks like a large
lollipop). I put a drop or two of mineral oil in the hole with the
thermometer. I place the flat aluminum side against the gel (or any flat
surface for which you want the temp) and read the temp with the
thermometer. It takes a few minutes for the aluminum block to reach the
temp of the gel. To secure it in place so that I can check on the gel temp
regularly, I just tape it against the gel.

If you don't have the facilities to make one, the fabrication center on
campus here can make you one for about $25. (Sorry that this sounds like
advertisement, thought someone might be in the predicament I was in). Can
accept a PO or a check made out to the University of Southern Mississippi.
You have to supply your own thermometer.

Very brief history: Tremendous amount of draft in the lab I'm in.
Circulation needed to cool room because of all the freezers, ovens, ultracold,
etc. Had trouble w/ DNA sequencing gel. Couldn't keep it hot for all the
draft. Had no way to measure gel temp accurately. Didn't think temp tape
(like ones used for aquarium) was very precise. Didn't want to spend a
couple of hundred dollars on surface temp probe. Thus designed the device
described above. Cheap and precise. Hope this helps someone.

Shiao Wang
University of Southern Mississippi

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