How to Make a 200m Dive Watch for $25

@JakeSea modifies a Casio F91 into a DIY dive watch and sends it 200m down to the bottom of the ocean to see if it can rival the most expensive scuba watches.
Directed and Edited by: Brett Hoffman
Featuring @JakeSea
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[@CCPwillfall01]

I love this video no 20 minute vlog bs just 100% quality content

[@Drownedinblood]

Casio proving once again they basically made the perfect functional watch.

[@mikeli3720]

Somehow, casio really understated their products, it's a lot more robust than they claimed

[@betulaobscura]

It is better to underrate than overrate.

[@HGSolberg]

@@betulaobscura Not according to Chinese watch manufacturers. LOL

[@azharulhisham1960]

Typical Japanese company philosophy. Never over promise, but always over deliver.

[@julioc.7760]

funny thing is, most guys who wear diving watches have never dive :(

[@yannisgk]

true!!!

[@michaelpeacock9420]

Very true I wear a g shock and it's never been in deep water 😅

[@julioc.7760]

@@michaelpeacock9420 mine doesnt even go in the shower.

[@yannisgk]

@@michaelpeacock9420 i wear the king of g-shocks and i don't even wash my hands!!!lol.

[@Maxumized]

Depends on what kinda diving😂

[@JakeSea]

Hi Everyone! Brett and I are very appreciative of all the support on this video. It has been amazing watching it explode in popularity. And while many of you appear to be watch enthusiasts (myself included), those of you here for the boating can still find us on my channel. Brett and I still make content together and would love to see you over there! We just might drop a few more watches to the bottom 😉

[@ucheucheuche]

0:28 "Watches that do more than keep time. They keep you ahead of your time" Popular in the 80s, 90s, 00s, 10s, 20s, 30s. TRUTH.

[@RafaelCarvalho-rd5lc]

My f91w is my go-to watch for surfing for years now and it has never let me down, even when taking 2m waves right in the face it acts like it ain't nothing

[@omgwtflmaololrotfl2368]

any watch that has a waterproof rating will do what you just said. even a el-cheapo will do it no problem. surfing and diving are 2 very different environments. 1 is extreme depth with lots of pressure the other just splashed on the surface... Taking a wave to the face what has that got to do with the watch....stupid comment

[@SamMaskery]

Great to hear thanks for the helpful comment! I’m thinking of giving my groomsmen a f91 w as wedding gifts and a few of us surf so this is great to know!

[@HGSolberg]

The oil filled watch will take a lot more pressure than 20 bar. Another benefit with this method is that you should be able to operate the buttons under water, without water finding it's way into the watch, something you are not supposed to do, even with the most expensive dive watches. I do believe it's a good idea to use silicone based oli instead of mineral oil, though, since mineral oils might have small amounts of corrosive components in them, that might harm the watch over time. I also believe mineral oil will yellow over time faster than silicon oil, but not 100% sure about that.

[@jayp4303]

I've been snorkeling with my stock F91W multiple times in salt water, and never had a problem with water intrusion or corrosion. Those are shallow depths, but I would say that it's more than just "water resistant". (Also I regularly do things like hose off my arms, take showers with it, dip into buckets of water, etc.) This video is a great idea for deeper depths, and it makes total sense. As long as the mineral oil doesn't eat into the plastic casing or gasket over time.

[@HGSolberg]

"As long as the mineral oil doesn't eat into the plastic casing or gasket over time." Or into the electronics. Silicone based oil is a safer choice than mineral oil. It's a bit more expensive, but you don't need much of it.

[@WyvernDotRed]

The "depth" rating is actually of equivalent pressure and does not include any increase of local pressure due to currents. So you tested it to a higher standard than what a watch pressure tester would, it's more like the "300M" rating. But hydro-modded watches are known to be practically infinitely waterproof, though with a bubble the caseback might dent in. What went wrong with the stock F91-W is that the inner air compressed so much, that the crystal pressed on the LCD and shattered it's glass. I've hydro-modded a B640M and a GBX-100 myself, with the latter the oil broke the screen, which I repaired with a new polariser. Another benefit is better viewing angles, especially under water, where the crystal doesn't turn in to a mirror beyond a certain angle. It is tricky to avoid a bubble from forming in the plastic housing of the module, which might get out over time. And depending on the used oil it might turn yellow or cause the gaskets to swell, the latter also happened to my GBX-100. Even still, stock F91-W are known to survive being used on actual dives, as Casio greatly understates their water ratings. Also, you commented on dive-watches being too expensive, but only mentioned Omega in the end. Perhaps the cheaper Vostok Amphibia divers, or Chinese imported ones would be interesting too. Just One More Watch recently showed a 1000M rated diver, though it's gaskets were smaller than a Vostok's and the F91-W's.

[@MichaelAChang]

"But hydro-modded watches are known to be practically infinitely waterproof" That's not quite true - there are many little devils in the details when you get into the technical nitty-gritties. Even SINN watches, the best known hydro-watches, are only rated at 5,000M for the (Ronda quartz) movement and 12,000M for the case. For movements such as the F91-W, the display will eventually crack under pressure whereas quartz movements without digital displays might survive deeper, but its hermetically sealed crystal and its thin circuit board might become the weakest links thereby limiting its dive depth. Also keep in mind that ocean depths below 200M is at about 4°C where oil viscosity becomes an important consideration for ticking hands. Filling an F91W with baby oil might be good enough for rock-n'-roll suiting the needs of most people, but getting down the deepest ocean depths is a whole different technical and scientific challenge that becomes much more involved than a 5 minute KZbin video.

[@WyvernDotRed]

@@MichaelAChang which is exactly what I meant with *practically*. As a general user who would wear a watch, even professionally diving, you would not exceed what the hydro-modded watch can take. Of course, in situations you can not enter yourself, this can be exceeded and cause the watch to break, in the ways you described. And it speaks for itself that in such a professional setting you should not depend on an uncertified modding project, at most using it as an additional backup to see how long it holds up.

[@Andrew__Smith]

Don’t talk about the Russian “VOSTOK”, this is completely shit, not a watch, and the staff of their factory supports the terror perpetrated by Putler in Ukraine.

[@HGSolberg]

@@MichaelAChang No one dives to 5,000 meters, unless inside a mini u-boat. Also, the SINN watches will take a lot more than what they are rated for.

[@julianhowarth1075]

Firstly, there's no such thing as a waterproof watch, only water resistant watches to varying depths, depending on their quality. An interesting experiment though and I'm not saying filling with oil wouldn't work. Two points though. As far as I'm aware, ordinary oil CAN be compressed and this is why we use hydraulic oil in machinery and brake fluid in vehicle braking systems. Brake fluid is chosen over ordinary engine oil 0:04 specifically because it cannot be compressed. Secondly, when a watch button is pressed for whatever reason, it's inevitable that oil will leak and air will enter the watch, affecting its water resistance. Thirdly, how does the oil react with the electronics within the watch ?.

[@incargeek]

I think this shows that the buttons are well sealed. If the non-oil watch buttons didnt seal, water would have seeped in to equalize the pressure, and the glass might not have broken. Of course, the electronics might have failed eventually in the salt water but its worth testing a pressure- equalized watch.

[@watchingdanny]

Excellent demo. And with the humble F91W too. Great job.

[@cameronj8827]

Very nice. Bell & Ross used this same science to create the hydro max, which is water resistant to 11,000 meters, but costs around $2500

[@batkorub]

many watchmakers do the same. for example sinn with their ux series has 5000m and 12000m oil filled divers

[@chrisp.5272]

Love my green F91W, it’s my landscaping watch, and I nicknamed it the Master Chief watch.

[@vasiovasio]

Super useful and practical video! Thank you Brett!

[@bernard1450]

If you press the buttons of the modded one, will the mineral oil seep out?

[@anhtuannguyen16799]

Nope it won't, there is a rubber gasket around the button

[@pablolara797]

​@anhtuannguyen16799 but oil can not be compressed. Therefore, the button can not be pressed, or if it can be pressed oil should flow outside. Well, the rubber can be compressed. Maybe enough to permit the button to work. I do not know for sure.

[@REVIEW_JUJUR]

It wont leak… i did hydromod to all my kids casio. It is really fun, and work fine so far.

[@MuhamadDjazuli.]

​@@REVIEW_JUJURbisa bang??

[@nicknameless5581]

​@@REVIEW_JUJUR but does the alarm work ?

[@fredericcolombier5380]

Casio are very reliable watches , my father like the Casio , he have plenty of them from the ealy 80's to today , for every day , they all works. Part of them , on their original Battery .

[@dieselgoinham]

🧢🧢🧢

[@johnstarks5323]

My issue is what are the long term effects of mineral oil on the internal components, and insulated coating on the pcb.

[@EddieHub21]

That's actually genius

[@vek7561]

Loved the video! was looking forward for such a explained mod and the test video itself! superb production quality looking forward to more such videos!!!

[@KidsInCombat]

I need to try this!!!! Thanks for sharing this

[@Anonnonon]

Now the remaining piece of the puzzle that will probably destroy all dive computers is adding a depth gauge to this bad boy ..

[@pixo4552]

Really great vid, thanks!

[@stoundingresults]

Poor Casio on the left sacrificed for science. 😔

[@thenexthobby]

So the internal components aren’t harmed by liquid until they’re assembled, leaving them vulnerable to liquid. Interesting.

[@bean_____Boi]

That was a cool video. Now I want one again

[@g_br]

Incredible!

[@Tom9mm]

Hey thank you for your video this is awesome I've been working around boats for a little while now and everybody tells me to get a watch that's at least 200 m water resistance but I don't really have the money for it and now I have solution to my problem thank you

[@vansh25]

casio duro, casio dw291hx are great 200m affordable options for you.

[@banesrbija1980]

It was just a casual hydro mod video all until the boat scene, then I knew that things are getting serious!

[@watch-highres]

Liquid moding really helps to many watches and also helps better magnification with diver watches with regular flat glass it creates dome style magnification effects too. Great video with lot of efforts to show test section.Thank you.I watched it even though I knew what the results will be. 😎👍 keep the good work us much as possbile

[@TaguroSuper]

The only downside is that you need to repeat the process once you need to replace the battery.😅

[@martin.tanubrata]

once every 7 years... I dont' mind

[@jinglemyberries866]

​@@martin.tanubrata same!

[@balazsszomor5964]

Actually you can surf or even snorkel in it out of the box. But good idea with the mod. :)

[@RCYT_]

Won't the internal components get spoiled with the oil??

[@villewintermaul1907]

Interesting the standard one completely exploded at exactly 200m❤

[@user-wd7sj5vk1j]

This also worked on my mechanical dive watch!!!

[@ginoongboyong]

That was fast!

[@davidd1016]

Awesome...well explained ...pressing the buttons on the oil filled watch still possible I'm assuming...not enough of the button entering the case that cannot be displaced forcing oil out?

[@TheBird..]

Lowkey clever as hell

[@JM-rw9je]

Anyone mentioning that badass gopro holding on those 200M???

[@MishMash22]

Now this is real science!

[@simonnomis5302]

man my fw91 can handle 30 meters...without oil and stuff

[@mbanzf]

can you same test with casio mdv 107 aka duro

[@fatihkymazarslan8308]

what a content hahah :D liked it so much!

[@adamzain6770]

A bit messy and unnecessary when you can usually get the Casio AE-2100W for half its listed price, at about 30 quid (i.e. probably $30 in the more favourable US market). That’s 200m water resistant and has a nice stainless steel front piece, mineral glass, a ten year battery and all the bells and whistles of the Royal, but with nicer looks.

[@nitindavid5691]

Nice video! Wish the dive watch was also tested

[@user-xf7ve1br2u]

Question #1. If mineral oil is not a conductor, what happens to the contacts from the battery to the contacts to the watch? Question #2. Oil is more viscous than air. In the case of classic watches. Will the viscosity of the oil affect the rotation of the needles and gears? What about the battery life?

[@ChrisLoew]

BRO, USE A SMALLER BOWL

[@vasiovasio]

This is America! They waste like No Tomorrow! 😂😂😂

[@johnberry2877]

Just buy a Timex Ironman problem solved. I have dove with a Timex for years in water from Michigan to Grand Cayman. Never flooded ! And way easier to set and use than the Casio.

[@abuabu1744]

100% waterproof

[@gabor222]

You could start with a Casio w59 which is about the same price but has better water resistance by default and mod that.

[@radmannavazani1860]

Could this process be done to an A168WA as well?

[@patricj951]

Interesting video! Just a note: the unmodified watch IMPLODED, not exploded.

[@richardmclean5913]

How long will the mov't last after being doused in mineral oil? It may be WR to 200M but a movement full of oil is likely to stop working soon.

[@eddiejones.redvees]

It would be great to do the same with a g shock to see how far past it’s 200M limit

[@takitam2521]

Are buttons still functional ar they will leak oil when pressed?

[@diomarim7322]

How long does this last though? Do we need to re-apply the oil every after dive use?

[@vismaykhant5992]

So intresting video..

[@MrGrentch]

Now, _that_ is very clever. 🙂👍👍

[@magnumopus9058]

How much weight does this mod add?

[@vitalioz]

F91W FTW!

[@smarteveryday1606]

omg, my family only wears casio. no money can give the satisfaction and trust like casio does at a fraction.

[@manuelribeiro8521]

Can you do that to a casio that is analog and digital at the same time such as casio AQ-800?

[@HGSolberg]

Yes, as long as it's a quarts movement, you can do it. Use the thinnest, most viscous silicone oil you can find, to interfere as little as possible with the hands' movement. Preferably lower than 40 cSt. In fact, because of the added resistance from the oil on the moving parts, it will wear out the battery faster. It will also introduce a tiny bit more wear on the gears. So, consider these drawbacks before you decide. Also, be aware that the oil will thicken with lower temperatures. So, if you leave the watch outside for a day in -30 degrees Celsius for example, that might be a problem. But if you wear it directly on your wrist, this shouldn't be an issue, even in cold temperaures. A fully digital watch with no moving parts won't have any of these problems. The watches you CAN NOT do this to are manual watches (wind up or automatic watches), because the oil will upset the balance wheel.

[@nunonunes097]

Pardon my dumb question, but how do you change the battery in a modded F-91W? Will the viscosity even allow it? And do you have to repeat the oil process?

[@jinglemyberries866]

just disassemble the watch over some paper towels or something and let the old oil run off the components and grab your new battery, submerge it and the other components in new oil and assemble the watch again.

[@Cockaboobledoo]

Thats crazy

[@alexsystems2001]

Ok that was a neat experiment

[@gerry9306]

Yes it was really swell too

[@zimbra67]

I wonder if hydro mod can improve the led light performance of f-91w.

[@shrishak00]

Bro casually showing how to hydro mod casio watch.

[@anakmuda5439]

damm this channel is underrated

[@arzsigma9]

By entering the mineral oil inside the watch, is it possible to access the watch's functions?

[@Unlucky1776]

Yea ofc

[@Bear-nu8xm]

I have this watch and I’m going to do this for fun! I wonder if it’ll work on any watch with gaskets?

[@HGSolberg]

Any water-resistant quartz watch. (The seals keep the oil inside.) You can not do this on a manual watch (winding or automatic), because the oil will upset the balance wheel.

[@Bear-nu8xm]

@@HGSolberg Thanks .This is what I supposed however, knowing for sure is a better outcome than a ruined watch.

[@HGSolberg]

@@Bear-nu8xm One thing, I noticed he used mineral oil. It's much better to use silicon-based oil. Mineral oil might in fact damage the rubber seals over time, and maybe even the electronics. Silicon oil is much safer. Mineral oil also yellows over time. If you do this on an analogue quartz watch there are a few things to consider: The oil will introduce a slight resistance to the hands and other moving parts, making the motor work a tiny bit harder. This means the battery will have a shorter lifespan, in addition to a little bit more wear on the gears. To minimize these drawbacks, you should use the lowest viscosity silicon oil you can find. Preferably lower than 40 cSt. Also, oil thickens with lower temperatues. So, for example if you leave your watch outside in -30 degrees Celsius (say you leave your watch in your car overnight in the middle of the winter for example) it might be a problem. As long as you wear your watch on your wrist, your body heat will be enough so that this won't be a problem, even in cold temperatures. Of course, none of the mentioned issues applies to a fully digital watch with no moving parts.

[@tahsinseckinyeni8008]

Freakin Google i just told my friend about this watch and 1 hr later this video appears on my list

[@leonardocozza3140]

Can i do the same Thing with W59 model?

[@newhuskytwenty]

Of course you can. I got two, the usual black and a special edition white but if they are guaranteed up to 50 meters you can be sure they can resist even more depth that you could reach scuba diving so it is pointless, no need to modify it at all. No human body could resist the water pressure 200 meters deep and I doubt even 100 meters even using a special air mixture in the tanks so if you die who cares about your cheap watch? Saludos desde España, soy buceador aficionado.

[@phiraphonnabangchang2911]

Perfect😊

[@DCAKAJ]

imagine doin this to a G shock

[@Danieldot2K]

I wonder what would happen if you were to try to press any buttons on the modded casio at 200m

[@saurabhjadhav1000]

I think it did not exploded, it imploded.

[@owenlaprath4135]

Mineral oil can damage your seals! Use silicon lube oil instead. There is O-ring lube-oil that should work very well.

[@RoberttSmithh]

Bruh that bowl could fit 20 watches at least. Could’ve done it with a cup

[@SaSpursFan]

stupid question but how does oil not damage the electrical components of the watch like water does

[@xoibor]

They only use oil that isn’t conductive so it doesn’t short any connections

[@sandsgrainofsand5320]

water is a circuits worst friend, on the other hand you can run a whole computer in mineral oil if you wanted to(fans and all)

[@ys-50989]

What about batteries?

[@femrebostan]

Can you compare Seiko and Rolex diver watches in the same way?

[@180ballybollock]

Talibian special,bet they didnt know about this

[@Unlucky1776]

Obama special too. He wore an f91 and so did Osama

[@FullTimePRO]

Just don' press that button to activate the light down there or you might have a problem ;) Also I've heard that the oil can expand and kinda weep if it gets hot out but YMMV.

[@kirxuir]

Yes, that's why it's better to use high-quality silicone oil.

[@user-xf7ve1br2u]

Dude, you hacked the system! 🎉

[@Flockingtheherd]

Mineral oil does go bad after a few years. Use flourinert if you want to make it last forever. Although kinda pricey

[@HGSolberg]

I'm thinking silicone-based oil is better than mineral oil, and a good compromise for most cheap watches. (People probably won't do this on expensive watches anyway.)

[@user-tz8sx4bo6v]

On the Amazon website it says that it can withstand 10 meters of water pressure. How is that?

[@jayp4303]

It's fine for snorkeling in my experience.

[@primulanera5798]

The truth is that , the American’s make this cheap watch famous & popular more than Japanese 😂

[@gerry9306]

It's important to you?

[@elmacho7561]

The fluorinert is great.¡

[@billsomerset238]

Are there seals on the pushers?

[@HGSolberg]

Yes.

[@gerry9306]

No

[@kirxuir]

no

[@billsomerset238]

What stops the oil from leaking from the pushers?

[@kirxuir]

​@@billsomerset238 the viscosity of the oil does not allow it to leak, if the untreated watch does not have water leaking up to 20 meters, then how will the oil leak without pressure and even much more viscous than water

[@designated_hitter_EGA]

imploded not exploded but enjoyed the vid, thank you.

[@djpaulhannon]

I bought a load of these while I was in Japan recently, for only $9.00 each brand new. In New Zealand, they would cost me 5x as much.

[@UncleMcTouchyBottom]

i swam miles with the F91 and it didnt bat an eye, strap needs to be textile though as the resin one disintegrated fairly quickly

[@bhavishaypoonia]

I just bought one and was wondering if it will survive in swimming pool with 10 ft depth ??

[@Long-Ball-Larry]

@@bhavishaypoonia Mine did, but I wouldn't push the buttons under water. But if you wanna play it safe you know what to do now. Once I also forgot to take my f-105w out of my pants and it survived a trip in the washing machine at 140°F including a spin cycle as well. I put a Nato strap on all of my 91w and 105w. So comfy.

[@lyhaikudai3]

So if a G shock get mineral oil it can go 1000m

[@gerry9306]

Let us know 😊

[@catstory1696]

nice 😊 tips! thank you! 200M the watches still workin, but Im die 😅,

[@Maxumized]

I have to clean my dirty bits? That’s crazy

[@Andrew__Smith]

There’s just one thing I didn’t understand: at what dive depth the unmodified watch *start* leaking?

[@kutter_ttl6786]

It looks like at 26m, you can already see the water intruding. It could've started earlier, though.

[@Andrew__Smith]

@@kutter_ttl6786 🤔

[@angeloreyes357]

Dont need a 200m 0 100meter watch..i cant even swim..😅 but casio watches are on my collection.good stuff..worth every penny.

[@earvinquero2037]

Osama knows

[@enginaktekin3444]

Model F-94 could have been more resistable than F-91. Because F-94 is lighter than F-91. So if you fall 20 m high, you will die or hurt but an ant fall, nothing will be done. It will carry on.

[@alvarojoseborreror.6588]

So now test how deep can it go!