Brands like Rolex and Omega will often tout their deepsea capabilities with the Rolex Deepsea Challenge rated to 11,000 meters (36,090 feet) and the Omega Ultra Deep coming in at a lesser but still ridiculous 6,000 meters (20,000 feet) of theoretical water resistance. But what about a cheap Casio often associated with terrorists and hipsters? With around $15 and some engineering know-how, can an affordable watch also venture into the deep ocean?
I wish the article didn’t skip the part about how they filled it up with mineral oil that sounds cool.
They do mention there’s lots of guides. I couldn’t find a wikihow, but here’s a forum link https://www.thewatchsite.com/threads/superlative-oil-filled-f-91wthe-making-of-the-superlative-oil-filled-casio-f-91.8273/