Casio F91w at 5KM underwater – watches of espionage

Re:Casio F91w at 5KM underwater – watches of espionage by dnisbet on Friday January 31, 2025 @11:01AM (#42888860)

Yep would have loved more on when the watch (unmodified) would actually break and also how you would fill it with oil? There can't be much space inside, at what point does the viscosity of the oil matter? how do you know you've got all the air out?

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Re:Casio F91w at 5KM underwater – watches of espionage by aidenn0 on Friday January 31, 2025 @11:23AM (#42889022)

I'm assuming they are using mineral oil; I've not filled a watch with mineral oil, but I have worked with it. Mineral oil is not particularly viscous; some gentle tapping is probably enough to get all the bubbles out.

Here's a video of a PC immersed in mineral oil with an aquarium bubbler and you can see the bubbles rise fairly quickly:

https://www.youtube.com/watch?v=tUBvWXH1hLs&t=110s

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