Waterproofing a contact sensor

I have 2 extra Lowe’s contact sensors now, and i’m thinking about using them to monitor some outdoor gates. Does anyone have any recommendations on how to waterproof the sensor? I’m considering filling the circuit board portion of the housing with silicon sealant or ShoeGoo, but it still leaves the battery terminal exposed. The case will help protect it some, but I have a feeling moisture will still get in. Any ideas? I have a 3D printer, so I may trying experimenting with different types of plastic

i need this also for a gate contact. i have 2 fence gates that need open/close and a moving entry gate that needs open/close.

I am going to try dipping them. Should create a weather tight seal.
Plasti Dip

@NMK95, what would you do when it comes time to replace the battery? I figured shoegoo or a similar type of adhesive would stay water tight, yet allow for a somewhat easy removal when needed.

Simple slice with the razor blade and it should peel off pretty easily.Then just re-dip after you changed out the battery. You can get a lot of re-coats out of a can. Figured it was a lot easier and cleaner than silicone.

If you want to do it right, the correct product to use is called a conformal coating. There are several different types of conformal coatings, but silicone is what you’ll want to use here.

Paint it all over the circuit board well and let it dry. It’s got an acetone base, so it doesn’t take long. Put the plastic case back on, and for all its worth, you could have it monitoring a gate at the bottom of a lake.

If you’re really anal like I am, I then spray/dab a little bit of corrosion inhibitor on the battery contacts, since you didn’t touch those with your conformal coating.

This is good stuff

I personally use this since I use it a lot, and it’s the size of a can of spray paint.

Not doubting that plasti-dip wouldn’t work, I just haven’t had very good luck or been impressed with it for other things around the shop long term.

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As an old electronics tech… I just go to Lowe’s and get a cheap squeeze tube of RTV. I use the clear kind do I can see the board.

Coat it in that stuff and you’re good to go…

That’s what we use in the Navy on airplanes.

@kars85 What if you dont use the corrosion inhibitor are you going to have an issue with that then?

Over time yes. You’ll know, but if you forgot that corrosion x also breaks rust down (as will your normal run of the mill penetrant, too)

Should I put some type of coat on the outside of the plastic of the contact sensor as well?

Or just use the silicon to coat the circuit board and the corrosion protector?