Waterproofing Temperature Sensors

Clark Martin

New Member
I'm new to this forum and to 1-wire. I was perusing the old messages and in one about waterproofing sensors Plasti-Dip was suggested. I've seen this type of product around in the past but couldn't find it in the hardware store today. I did however find Liquid Electrical Tape.

I bought some and have dipped one DS1820 so far. I only did it today so it's not fully cured and therefore I haven't tested it out. But I wanted to bring it up and point out a couple of advantages over Plasti-Dip.

First, it's made for insulating 120VAC wiring so it should have essentially no electrical impact, specifically resistance. I don't know if other products do or don't but something made for dipping tools may well a poor electrical characteristic since it doesn't matter in the original application.

Second, I think it's quite a bit thinner than Plasti-Dip. It certainly worked it's way in and around all the wires. I used twisted pair I pulled out of a commercial CAT-5 cable. This wire is stranded and so doesn't have the usually springiness of solid CAT-5. Later I'm going to try dipping the last 6-12 inches of the wire to seal it up, cable like. I want to place the probe in liquids and I figure it's better to not get the pair in contact with the liquid. More to keep water from wicking up the pair than worry that the wire isn't watertight.

I also daubed some Liquid Electrical Tape into the open end of the RJ-11 connector on the other end of the probe. It filled the opening and even wicked it's way up into the two unused wire holes. But it isn't leaking out anywhere. I also daubed it around the wire as it enters the connector providing something of a strain relief.
I've use both and they are nearly identical products. The Plasti-dip I just bought was as thin as the electrical tape I've used in the past. Depending on how long they have been left open, they tend to thicken.
I have used "Marine Epoxy" from ACE hardware to weatherproof/protect components with good results.
It cures in a couple of hours and is very durable. It is not flexible so might not be the right
choice in all situations. I have used it for sealing surface mount chips soldered into a DIP socket,
around a PIN diode used to detect solar radiation, and over the back of perf board to protect wiring.

If you do intend to use epoxy you should test the electrical resistance prior to applying it to your
component. Let a blob cure and then probe it with an ohm meter.

I do not know what the long term performance would be or how UV stable the epoxy is - so use at
your own risk.

I attached two pictures showing how the epoxy is used.

1) protective coating for surface mount chip soldered into DIP holder
2) back of perf board to protect wiring


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  • powerInjector_epoxy.jpg
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