LED Flashlight Switch Repair Failure

This didn’t work out, but it came close. Eventually I’ll figure out what material can replace the boot, at which point I’ll need to remember these steps…

That LED flashlight + laser pointer has a rubber boot over the push-on / push-off switch stem that makes it sorta-kinda waterproof. Although I wouldn’t trust it in more than a sprinkle, it’s my pocket flashlight and tends not to get soaked very often.

Anyhow, the rubber boot wore through:

Broken switch boot
Broken switch boot

Taking it apart, now that I know how, was easy enough:

Switch button parts
Switch button parts

Note that the mushroom part goes on the outside, which means the stem will vanish if the boot rips apart.

I planned to mold a boot from acrylic caulk, so I wrapped narrow strips of electrical tape to match the stem to the mushroom head, then wrapped a bit around that to make the final boot fit loosely:

Wrapped switch stem
Wrapped switch stem

A thin layer of oil served as mold release, over which I smoothed a blob of caulk. This looks awful, but the majority of the blob at the bottom will get trimmed off:

Switch stem covered with acrylic caulk
Switch stem covered with acrylic caulk

Unfortunately, the cured caulk turned out to be remarkably fragile. Each individual blob felt tough, but it’s really not designed to form thin membranes; I got about what I expected.

Pourable silicone rubber seems like the right hammer for the job: make an outer mold to surround this thing (or a 3D printed replica) and pour it on. I must get some of that, one of these days.

So I put the flashlight back together with the mushroom on the inside to keep the stem in place… and I generally avoid getting more than knee-deep in liquids, so not having a good seal won’t matter too much.