Salt Water Brackish Water Articles DIY

How to protect metal temperature probes from salty water

Today I will show you a simple escamotage to protect the temperature probes with metal head from corrosion of sea water.

Lately, I have often done DIY projects, especially in aquariums, where the use of temperature probes for salty water in your aquarium was required. As long as these probes are plastic all fine, but sometimes you can or should use metal probes, such as temperature probes for Arduino microcontroller.

It takes just a few months to corrode the heads of these probes and this certainly does not work for the probe or the inhabitants of your aquarium, as the metal definitely releases unwanted substances.

For this reason, I was tired of having to replace them continually, I thought to protect them with something that would waterproof them but at the same time did not alter their temperature reading capabilities.

Some of you will remember that a few months ago we have edited an article on “How to Build a Wood and Glass Fiber” and it’s just where I thought I would use the same resin to protect the probes.

But let’s get to that!


epoxy resin with its catalyst (typically sold together).
one or more probes that we want to waterproof.
plastic cup for coffee.
a cylindrical container (I used a 10ml glass flask to be threw away) or more than one if you had to deal with multiple probes.
Gloves and mask.

(First, protect yourself with gloves and possibly a mask as some resins are quite toxic to breathe and contact and perform the operation outside).

Pour the resin and the catalyst into the plastic glass, following the recommended doses on the packaging.

Mix the two components with a wooden block (which then we will go off) until they are well mixed with each other and pour the liquid inside the cylindrical container, a very small glass flask in my case.

At this point I would wait a few minutes until the resin gained the honey consistency (if the room temperature is 25-30 degrees may take a few minutes) you can insert the tip of the probe into the flask, making sure that it is drenched well a little on the cable and not just on the metal head of the probe. Take the probe out right away of the container (otherwise if you leave it too much time it might dry up and you will not take it out anymore!) and hang it somewhere, be careful not to drip it on the floor, otherwise it will not be easy to remove, so it’s best to do everything outside.

Once dry, spend a couple of days, just to make sure it’s dry. You may also feel it touch, if it is still sticky after a day it’s okay, you probably missed the catalyst dose or the temperature might be too low. If it is dry then it is ready to be inserted into the water!

You will have fitted your probe of an absolutely watertight film, which does not affect the correct temperature reading but will give you eternal life 🙂

Appassionato di informatica ed elettronica sin dall'infanzia, sempre in deficit di conoscenza, ho trovato in questo affascinante universo dell'acquariofilia l'argomento che riesce a stimolarmi ma mai a saziarmi abbastanza da diventare noioso!

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