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Topic: How to Waterproof TMP36 temperature sensor? (Read 7874 times) previous topic - next topic


Hi Everyone
I have searched through the posts looking for information on how to waterproof a TMP36 sensor. I need a few temperature sensors for my heat exchanger and need to waterproof them.
I see we have in our local hardware (Builders Warehouse) an insulation spray paint (haven't used it before) and was wondering if something like this could work?
Also, what have other people done as I'm sure I cant be the only person that needs waterproof temperature sensors (specifically the TMP36)

Any advice much appreciated.


If it isn't already waterproof, there isn't much point in bothering when you can get a DS18B20 that already is. This morning I even saw an adaptor that should be good for mains pressure water, although they are simple enough to make yourself.



Nicks idea is best but if you  already have bought them then just coat them with epoxy like the manufacturers do... are you sure that they are not already water proof?



Thanks for all the replies - much appreciated!

Just to confirm, are the TMP36's already waterproof? If I put epoxy around the 3 pins that should be OK?



That probably will be OK, the body is sealed, but you might as well coat the whole thing. it will end up having a little slower temp response, but then you know the wires are completely sealed.


Something we found out when doing something similar was that if you weren't careful, water could creep down the wires themselves if they were not properly sealed.  However we then sealed everything with epoxy.  You can also get thermally conductive epoxy as well, and that will speed up the temperature response time. 


The best method is what is called a "conformal coating" it's what is used commercially to waterproof PCB's. Most are variants on a soft urethane type of plastic dissolved in a solvent. They can be applied with a brush, dipping or simply pouring the material over the area to be protected and pouring off the excess. Occasionally some solvent needs to be replaced due to evaporative loss. I've used all three methods with great success.
The material is soft enough to be removed with a thumbnail for repairs and resistand to water and most common solvents as well once dried.

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