8 ms·

I wrote about the F-91W last year in a post[1] that went viral-ish. Interestingly, it's probably the only article of clothing worn by both Obama[2], and Osama[3

by dvt 6y ago

I wrote about the F-91W last year in a post[1] that went viral-ish. Interestingly, it's probably the only article of clothing worn by both Obama[2], and Osama[3]. I wouldn't go as far as calling it a "terrorist icon" -- it just happens to be literally the cheapest mass-produced digital watch ever made. It's very sturdy, relatively waterproof, the battery should last around a decade, and it even has a (terrible) LED for low light conditions! I started getting into watches last year, and the F-91W is a sort of rite of passage in watch circles. I've since bought a few expensive† ($1000+) watches for my collection, but I often find myself wearing the Casio. Yeah, I modded it and it has a bit of personal attachment, but it's not just that. There's something really strange about it: it fits so snugly on my wrist, so warm, yet spartan; it simply just feels good. [1] https://dvt.name/2019/06/03/hacking-the-casio-f-91w-to-handle-1000-psi/ https://dvt.name/2019/06/03/hacking-the-casio-f-91w-to-handl... [2] https://static.highsnobiety.com/thumbor/hC8faiWSsiFpNpszRf0lb7yAkIA=/fit-in/960x550/smart/static.highsnobiety.com/wp-content/uploads/2015/09/Casio_F-91W_terrorist-002.jpg https://static.highsnobiety.com/thumbor/hC8faiWSsiFpNpszRf0l... [3] http://ethiopiaforums.com/wp-content/uploads/2010/05/osama-bin-laden-seated.jpg http://ethiopiaforums.com/wp-content/uploads/2010/05/osama-b... † This is of course relative. Watches can cost up to millions, and serious watch collectors have watches that can easily go up to $50,000++.

deleted 6y ago
[deleted]
notRobot 6y ago
What mods did you make to your Casio?
- dvt 6y ago
  I filled it with mineral oil and gave it a NATO strap, see my first link!
  - austhrow743 6y ago
    Very cool idea. Haven't had any leakage issues since doing it?
    - dvt 6y ago
      Nope! I was a bit worried about flying with it, but no leaks there either.
- shalmanese 6y ago
  /r/F91Ws_on_NATOs/ is a subreddit specifically dedicated to modding F91Ws with NATO straps and other mod ideas. https://www.reddit.com/r/F91Ws_on_NATOs/ https://www.reddit.com/r/F91Ws_on_NATOs/
creeble 6y ago
I'm a bit of a Casio watch collector; I think the count is currently about 10. Three of them are variations on the F91W, including the metal-banded A158W. I also have several MQ24's (analog face, ~$10). There's an F91W that has a "gold" case too, for just a couple dollars more. If you watch Napoleon Dynamite closely, you'll note that Napoleon has an F91W, but his "classy" uncle has an A158W. It was funny to someone like me.
- dvt 6y ago
  > If you watch Napoleon Dynamite closely, you'll note that Napoleon has an F91W, but his "classy" uncle has an A158W. It was funny to someone like me. Hah, I definitely missed this detail, I must've last seen Napoleon Dynamite years ago.
pgreenwood 6y ago
What oil soluble dye did you use? I was looking for oil dyes for another project and I found them hard to find.
- dvt 6y ago
  Lamp oil dye, this is the exact pack I got: https://www.amazon.com/Firefly-Colored-Smokeless-Odorless-Paraffin/dp/B00NJ69X4Q/ https://www.amazon.com/Firefly-Colored-Smokeless-Odorless-Pa...
GekkePrutser 6y ago
Terrible LED? I thought that blue illuminator was super cool. And it was actually an EL film, not an LED.
- dvt 6y ago
  I think you're thinking of a different watch. The F-91W has a green LED[1] that's notoriously terrible (not to mention lopsided). [1] https://www.instructables.com/id/Watch-LED-Light-Mod/ https://www.instructables.com/id/Watch-LED-Light-Mod/
  - GekkePrutser 6y ago
    Ah yes indeed, I had the F-105W. I thought the F-91W also had this EL film, because it's also labeled "Illuminator" on the big picture at the top of the article, which was casio's branding for this technology at the time. But it doesn't have the blue branding. And I think that pic at the top isn't actually an F-91W. The EL light was super, very bright and very well distributed (because the whole backlight film would light up). I'm surprised they managed to put one in such a small watch as EL film needs fairly high voltages, you could hear the switching coil whine when it was on :P Yet it still lasted a good while on battery.
    - TedDoesntTalk 6y ago
      The F105W is what you graduate to after you realize the F-91W is essentially useless is the dark. I've worn both since the early 90s. The band always breaks before the battery or watch itself dies, but i still get a few years before the band breaks.
    - vinay427 6y ago
      The somewhat more complicated and modern Casio watch I had also had this EL whine. Now I finally found out why it occurs, so thanks for that! The silent F-91W was almost pleasant in comparison despite its uneven and (IMO) not very pretty lighting.
kennywinker 6y ago
Just wanted to say that I read your blog post when it first went around last year, and it made me fall in love with the look and the idea of the f91w. Currently have three, all found in thrift stores. They are functional, aesthetically pleasing, and such an affordable collectable. So, thanks! :)
- dvt 6y ago
  Thanks and that's awesome, enjoy your collection!
paulgerhardt 6y ago
Claude Shannon defined information in part by its ability to distinguish from noise. Certain objects are so ubiquitous and their signaling so minimal, it’s to the point of background noise and contextlessness. The Casio F-91W is one such object. The monobloc chair is another[1]. The community jokes a CIA analyst looking at a gritty Polaroid of a monobloc will have no ability to discern if the picture was taken in Djibouti or Denmark. In a certain, Cayce Pollard / William Gibson “CPU” aesthetic, there is cachet and delight in signalling contextlessness - and a small cult has grown around these objects. They collectively call objects that share this anonymous property “monoblocs“ for short and their is a bit of fun in acquiring the most base form (counter to our every instinct!) I liked your article’s tangent on incompressibility. As, like fluid, noise is incompressible and by reinforcing your F-91W, you have made it doubly so. [1] http://www.ethanzuckerman.com/blog/2011/04/06/those-white-plastic-chairs-the-monobloc-and-the-context-free-object/ http://www.ethanzuckerman.com/blog/2011/04/06/those-white-pl...
- dvt 6y ago
  This is an awesome comment, thank you! I had no idea of this new "monobloc" trend, but I feel like you're on to something. When I wear, say, my Longines Diver and I look at my wrist, I feel that my watch is communicating: it's an intricate, hand-built machine telling me the time. I need to wind it and breathe new life into it. I get complimented on it: "new watch?" or "nice watch, what is it?" It's an accessory. A deliberate choice. When I look down at my F-91W, it's as if it's not even there. I'm the one telling the time. Everyone ignores it, no one mentions it, no one brings it up: it's there but it's not. Just like a monobloc chair or a #2 pencil.
- shoo 6y ago
  https://en.wikipedia.org/wiki/Cayce_Pollard#Apparel https://en.wikipedia.org/wiki/Cayce_Pollard#Apparel
- rozab 6y ago
  There is a YouTube channel called Bryan Ropar's Plastic Chair World[0]. Bryan is an expert when it comes to these monobloc chairs, and can name every model by sight and tell you where it was produced. I think we often underestimate how much depth there is to subjects we are only casually familiar with, and I'm sure a CIA analyst could glean a great deal of information from a still of a plastic chair. [0]: https://youtu.be/yCotpBAqJho https://youtu.be/yCotpBAqJho
Polylactic_acid 6y ago
I also have a few expensive watches and the F-91W is my go to watch where I don't care about breaking it. It has been through bike crashes, slapped on the sides of water slides and all kinds of abuse. Its just a great product for some use cases.
bargle0 6y ago
I was inspired to replicate your hack for myself. It was a fun afternoon, and that watch keeps going (though I had to carve away plastic to get the band on). Thanks!
zabil 6y ago
> There's something really strange about it: it fits so snugly on my wrist, so warm, yet spartan; it simply just feels good. Totally agree. And it's great utility because of this. You can use it while playing, sports, music and it doesn't get in the way. There's no anxiety of busting and if you do it's cheap to replace.
- nonamenoslogan 6y ago
  This is exactly why I love the simple Casio designs too. The F91W is so light and simple, and I have ZERO fear of washing my hands with it or bashing it in to the wall while pulling cables. I usually forego the F91W for something like the WS1200 or the SPH-600, usually about double the price of the F91W but with a bunch more features AND still not scary to wear in any situation.
488643689 6y ago
I hate the buttons on that watch. They are prominent enough to always get stuck with whatever I slip my arm through. Especially backpack straps. Otherwise love it. The battery lasts longer than the plastics. Has this timeless 80s chic of the original Walkman and Thinkpads. I would love the calculator one more, but that is critically missing a light, which makes it impractical.
- EricE 6y ago
  Pretty sure my Casio calculator watch has a light since I remember using it. If I could just remember where I stashed it...
  - 488643689 6y ago
    The CA-53W doesn't have it.
stevekemp 6y ago
I've always been fascinated by mechanical things, steam-engines, analog watches, analog clocks, etc. (I've a few of each). The only digital watch I own is the F-91W, and I think it makes a nice contrast between the watches I wear more regularly.
jstanley 6y ago
I enjoyed your blog post, that's an interesting mod. > Some sources suggest heating the mineral oil to ~50° Centigrade, but I’m not exactly sure what the reasoning for that might be, so I stuck with room temperature. I expect this is just to reduce the viscosity of the oil so that it fills the cracks more easily.
- goatsi 6y ago
  There was some discussion the last time it came up on HN [0]. The thought is it might also help prevent air bubbles. [0] https://news.ycombinator.com/item?id=20079488 https://news.ycombinator.com/item?id=20079488
fierarul 6y ago
Oddly enough the Casio classics are starting to have quite a premium here due to the retro look. I've seen as capable digital watches at 1/3rd the price at the local Decathlon. Casio is milking their legacy quite a bit.
- EricE 6y ago
  Ha, still have my casio watch calculator from the 80's Guess I should see if the battery has exploded and if not get it out of there :/
deleted 6y ago
[deleted]
rattray 6y ago
Also a big fan of modding F91W's and other Casio's. My favorite is the Casio FE10-1A which doesn't look as good but whose face shows the numbers more clearly at a variety of angles and lighting conditions. I like to replace the watch bands with a pair of elastic hairbands. It makes the watches much lighter and more comfortable in a variety of scenarios: - Running (doesn't bounce around or get sweaty) - Yoga/pushups (can bend wrist fully) - Typing on a laptop (wristband doesn't hit the edge) I do have to change out the elastic hairbands every 4 months or so as they stretch out, and there's about a week of breaking it in where the new bands are too tight. Otherwise it's so great I'd seek to commercialize it. Photos: https://imgur.com/a/qNJ4MuG https://imgur.com/a/qNJ4MuG If anyone wants to try it out and could use some tips let me know.
- jansan 6y ago
  Modding the F91W was a nice Corona project that I did with my kids. Inverting the display, changing the led and inserting an nfc chip. Not too difficult, but it gives you something unique(ish) that is actually useful.
sq_ 6y ago
Thank you for that post last year! It inspired my friend and I to spend a day having fun modding a few we picked up. Still no water intrusion after over a year of near-daily wear...
EricE 6y ago
>I wouldn't go as far as calling it a "terrorist icon" -- it just happens to be literally the cheapest mass-produced digital watch ever made. It's very sturdy, relatively waterproof, the battery should last around a decade, and it even has a (terrible) LED for low light conditions! Yes, the article even points out four chaplains also wore it. "Cheap, reliable and common watch is also popular with terrorists" isn't as sexy a headline though.

by dvt 6y ago

deleted 6y ago

[deleted]

notRobot 6y ago

What mods did you make to your Casio?

dvt 6y ago
I filled it with mineral oil and gave it a NATO strap, see my first link!
- austhrow743 6y ago
  Very cool idea. Haven't had any leakage issues since doing it?
  - dvt 6y ago
    Nope! I was a bit worried about flying with it, but no leaks there either.
shalmanese 6y ago
/r/F91Ws_on_NATOs/ is a subreddit specifically dedicated to modding F91Ws with NATO straps and other mod ideas. https://www.reddit.com/r/F91Ws_on_NATOs/ https://www.reddit.com/r/F91Ws_on_NATOs/

creeble 6y ago

I'm a bit of a Casio watch collector; I think the count is currently about 10. Three of them are variations on the F91W, including the metal-banded A158W. I also have several MQ24's (analog face, ~$10). There's an F91W that has a "gold" case too, for just a couple dollars more. If you watch Napoleon Dynamite closely, you'll note that Napoleon has an F91W, but his "classy" uncle has an A158W. It was funny to someone like me.

dvt 6y ago
> If you watch Napoleon Dynamite closely, you'll note that Napoleon has an F91W, but his "classy" uncle has an A158W. It was funny to someone like me. Hah, I definitely missed this detail, I must've last seen Napoleon Dynamite years ago.

pgreenwood 6y ago

What oil soluble dye did you use? I was looking for oil dyes for another project and I found them hard to find.

dvt 6y ago
Lamp oil dye, this is the exact pack I got: https://www.amazon.com/Firefly-Colored-Smokeless-Odorless-Paraffin/dp/B00NJ69X4Q/ https://www.amazon.com/Firefly-Colored-Smokeless-Odorless-Pa...

GekkePrutser 6y ago

Terrible LED? I thought that blue illuminator was super cool. And it was actually an EL film, not an LED.

dvt 6y ago
I think you're thinking of a different watch. The F-91W has a green LED[1] that's notoriously terrible (not to mention lopsided). [1] https://www.instructables.com/id/Watch-LED-Light-Mod/ https://www.instructables.com/id/Watch-LED-Light-Mod/
- GekkePrutser 6y ago
  Ah yes indeed, I had the F-105W. I thought the F-91W also had this EL film, because it's also labeled "Illuminator" on the big picture at the top of the article, which was casio's branding for this technology at the time. But it doesn't have the blue branding. And I think that pic at the top isn't actually an F-91W. The EL light was super, very bright and very well distributed (because the whole backlight film would light up). I'm surprised they managed to put one in such a small watch as EL film needs fairly high voltages, you could hear the switching coil whine when it was on :P Yet it still lasted a good while on battery.
  - TedDoesntTalk 6y ago
    The F105W is what you graduate to after you realize the F-91W is essentially useless is the dark. I've worn both since the early 90s. The band always breaks before the battery or watch itself dies, but i still get a few years before the band breaks.
  - vinay427 6y ago
    The somewhat more complicated and modern Casio watch I had also had this EL whine. Now I finally found out why it occurs, so thanks for that! The silent F-91W was almost pleasant in comparison despite its uneven and (IMO) not very pretty lighting.

kennywinker 6y ago

Just wanted to say that I read your blog post when it first went around last year, and it made me fall in love with the look and the idea of the f91w. Currently have three, all found in thrift stores. They are functional, aesthetically pleasing, and such an affordable collectable. So, thanks! :)

dvt 6y ago
Thanks and that's awesome, enjoy your collection!

paulgerhardt 6y ago

Claude Shannon defined information in part by its ability to distinguish from noise. Certain objects are so ubiquitous and their signaling so minimal, it’s to the point of background noise and contextlessness. The Casio F-91W is one such object. The monobloc chair is another[1]. The community jokes a CIA analyst looking at a gritty Polaroid of a monobloc will have no ability to discern if the picture was taken in Djibouti or Denmark. In a certain, Cayce Pollard / William Gibson “CPU” aesthetic, there is cachet and delight in signalling contextlessness - and a small cult has grown around these objects. They collectively call objects that share this anonymous property “monoblocs“ for short and their is a bit of fun in acquiring the most base form (counter to our every instinct!) I liked your article’s tangent on incompressibility. As, like fluid, noise is incompressible and by reinforcing your F-91W, you have made it doubly so. [1] http://www.ethanzuckerman.com/blog/2011/04/06/those-white-plastic-chairs-the-monobloc-and-the-context-free-object/ http://www.ethanzuckerman.com/blog/2011/04/06/those-white-pl...

dvt 6y ago
This is an awesome comment, thank you! I had no idea of this new "monobloc" trend, but I feel like you're on to something. When I wear, say, my Longines Diver and I look at my wrist, I feel that my watch is communicating: it's an intricate, hand-built machine telling me the time. I need to wind it and breathe new life into it. I get complimented on it: "new watch?" or "nice watch, what is it?" It's an accessory. A deliberate choice. When I look down at my F-91W, it's as if it's not even there. I'm the one telling the time. Everyone ignores it, no one mentions it, no one brings it up: it's there but it's not. Just like a monobloc chair or a #2 pencil.
shoo 6y ago
https://en.wikipedia.org/wiki/Cayce_Pollard#Apparel https://en.wikipedia.org/wiki/Cayce_Pollard#Apparel
rozab 6y ago
There is a YouTube channel called Bryan Ropar's Plastic Chair World[0]. Bryan is an expert when it comes to these monobloc chairs, and can name every model by sight and tell you where it was produced. I think we often underestimate how much depth there is to subjects we are only casually familiar with, and I'm sure a CIA analyst could glean a great deal of information from a still of a plastic chair. [0]: https://youtu.be/yCotpBAqJho https://youtu.be/yCotpBAqJho

Polylactic_acid 6y ago

I also have a few expensive watches and the F-91W is my go to watch where I don't care about breaking it. It has been through bike crashes, slapped on the sides of water slides and all kinds of abuse. Its just a great product for some use cases.

bargle0 6y ago

I was inspired to replicate your hack for myself. It was a fun afternoon, and that watch keeps going (though I had to carve away plastic to get the band on). Thanks!

zabil 6y ago

> There's something really strange about it: it fits so snugly on my wrist, so warm, yet spartan; it simply just feels good. Totally agree. And it's great utility because of this. You can use it while playing, sports, music and it doesn't get in the way. There's no anxiety of busting and if you do it's cheap to replace.

nonamenoslogan 6y ago
This is exactly why I love the simple Casio designs too. The F91W is so light and simple, and I have ZERO fear of washing my hands with it or bashing it in to the wall while pulling cables. I usually forego the F91W for something like the WS1200 or the SPH-600, usually about double the price of the F91W but with a bunch more features AND still not scary to wear in any situation.

488643689 6y ago

I hate the buttons on that watch. They are prominent enough to always get stuck with whatever I slip my arm through. Especially backpack straps. Otherwise love it. The battery lasts longer than the plastics. Has this timeless 80s chic of the original Walkman and Thinkpads. I would love the calculator one more, but that is critically missing a light, which makes it impractical.

EricE 6y ago
Pretty sure my Casio calculator watch has a light since I remember using it. If I could just remember where I stashed it...
- 488643689 6y ago
  The CA-53W doesn't have it.

stevekemp 6y ago

I've always been fascinated by mechanical things, steam-engines, analog watches, analog clocks, etc. (I've a few of each). The only digital watch I own is the F-91W, and I think it makes a nice contrast between the watches I wear more regularly.

jstanley 6y ago

I enjoyed your blog post, that's an interesting mod. > Some sources suggest heating the mineral oil to ~50° Centigrade, but I’m not exactly sure what the reasoning for that might be, so I stuck with room temperature. I expect this is just to reduce the viscosity of the oil so that it fills the cracks more easily.

goatsi 6y ago
There was some discussion the last time it came up on HN [0]. The thought is it might also help prevent air bubbles. [0] https://news.ycombinator.com/item?id=20079488 https://news.ycombinator.com/item?id=20079488

fierarul 6y ago

Oddly enough the Casio classics are starting to have quite a premium here due to the retro look. I've seen as capable digital watches at 1/3rd the price at the local Decathlon. Casio is milking their legacy quite a bit.

EricE 6y ago
Ha, still have my casio watch calculator from the 80's Guess I should see if the battery has exploded and if not get it out of there :/

deleted 6y ago

[deleted]

rattray 6y ago

Also a big fan of modding F91W's and other Casio's. My favorite is the Casio FE10-1A which doesn't look as good but whose face shows the numbers more clearly at a variety of angles and lighting conditions. I like to replace the watch bands with a pair of elastic hairbands. It makes the watches much lighter and more comfortable in a variety of scenarios: - Running (doesn't bounce around or get sweaty) - Yoga/pushups (can bend wrist fully) - Typing on a laptop (wristband doesn't hit the edge) I do have to change out the elastic hairbands every 4 months or so as they stretch out, and there's about a week of breaking it in where the new bands are too tight. Otherwise it's so great I'd seek to commercialize it. Photos: https://imgur.com/a/qNJ4MuG https://imgur.com/a/qNJ4MuG If anyone wants to try it out and could use some tips let me know.

jansan 6y ago
Modding the F91W was a nice Corona project that I did with my kids. Inverting the display, changing the led and inserting an nfc chip. Not too difficult, but it gives you something unique(ish) that is actually useful.

sq_ 6y ago

Thank you for that post last year! It inspired my friend and I to spend a day having fun modding a few we picked up. Still no water intrusion after over a year of near-daily wear...

EricE 6y ago

>I wouldn't go as far as calling it a "terrorist icon" -- it just happens to be literally the cheapest mass-produced digital watch ever made. It's very sturdy, relatively waterproof, the battery should last around a decade, and it even has a (terrible) LED for low light conditions! Yes, the article even points out four chaplains also wore it. "Cheap, reliable and common watch is also popular with terrorists" isn't as sexy a headline though.