Enclosures for outdoors, sealing gaps

Hi, I’m thinking of tiny enclosures for microcontroller projects - with battery - outdoors, and there are plenty of weather sealed plastic enclosures that are suitable, but what are the best ways to maintain a seal when you want to drill a hole and poke something out?

Like a 5mm LED or PIR sensor, both round and plastic. My current though is kind of put a bead of epoxy around the back of the component on the inside, to seal it that way, does that sound good? Kind of feels like it’d be easier to work with than silicone sealant for the same job. Or is there some other trick or problem with my thinking?

So far this would be for under eaves so not critical to be sealed against immersion or direct rain, but needs to hold up to some weather.

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Silicone. Lots and lots of silicone.

Also conformal coating. And tupperware. Tupperware is my favourite enclosure for the elements.

Oliver is exactly right. Lots of silicone (or epoxy) is the best way to ensure that the connection is weather-resistant (although in my experience this doesn’t work perfectly every time if you intend to submerge it) as for the common kind of waterproof seals used in industry, what you’re after is called a grommet or cable gland, we’ve got a few built in to some of our cases, as well as seperate parts, such as those which I’ve linked below

It really depends on the application, but for some simple inexpensive weatherproofing, a Tupperware container with silicone should do the trick. Also, be sure to read up on IP ratings if you’re curious about industry standards:


Have a great day!