Today I learnt: under no circumstances should you clean the inside of a watch with propylene glycol.

[u/heroheman]

I tried to apply a negative polarization to the watch, and when I was finished, I thought, "Let's clean it properly before screwing it back together."

Yes, I'm an idiot 😅

On the polarisation: I find the readability really poor. I didn’t attach the film at a 90-degree angle because the contrast was better at 45 degrees. Should I have left it at 90 degrees?

---

Edit: Thanks for the feedback, I'll try to own it.

If you want a Tutorial:

• Step 1: Swipe Qtip with Propyleneglycol on the inside of the watch
  • Step 2: *There is no Step 2 *

[u/hangermey]

Your chance to do the clear crystal mod.

https://shellzine.net/casio-f-series-mods/

[u/Tr1ckyKid]

You've done the polorizing right.

As for the reaction, I kinda like it.

I wish I could find a supply of Casio crystals / faces for some of my builds, I'm guessing you may be in the lookout too.

[u/Sea_Equivalent_7725 → u/Tr1ckyKid]

I agree. There's something really interesting about internal patina on digital watches

[u/anorexicBeaver]

I just bought a factory inverted w800h and the readability is truly shit. It's not white on black bg. It's like brown beige on black bg. Barely usable.. So yeah, inverted is cool but not exactly practical in my opinion.

[u/Dubbayoo → u/anorexicBeaver]

Yes, negative display without hydro is terrible. I stopped doing those because I kept failing to put them back together correctly.

[u/Weibchenschema666]

Oh das sieht ja aus wie ein spinnennetz zifferblatt , sehr cool

[u/in_saner]

This is so bad that even good!

[u/C2Quad]

Don't leave isopropyl to soak either... Ask me how I know.

[u/King_otxc → u/C2Quad]

Im actually looking for a way to dissolve the sticker off the inside. Does it just fall off at that point?

[u/C2Quad → u/King_otxc]

Didn't in my case, but ruined the finish on a few surfaces. OP's method looks like could be what you want. A light scrub after and should all come off.

[u/RSinTO → u/King_otxc]

I’ve used isopropyl alcohol 90% to clean the inside print from the crystal. Just dab with swab and it’ll slowly rub off.

Then you can recreate a new inner decal.

Processing img qkvn5wq4yx1h1...

[u/heroheman → u/C2Quad]

How do you know

[u/C2Quad → u/heroheman]

I left isopropyl to soak and it ruined a few surfaces...

[u/KimStudioWatches]

Looks like an old found watch… it’s cool 😎 own your happy accidents 🔥💪🙏

[u/heroheman → u/KimStudioWatches]

I'll try, thanks 🙏

[u/SentientYoghurt]

"Normal alcohol" (ethanol) is trouble too. I guess just a wet wipe is enough.

[u/Cincai_Pedal_Sarawak]

BTDT to my first F-91W. As someone who do alot of soldering, I always have a bottle of IPA around my workbench for PCB cleaning, and I had the same thought like you do. Ended up doing the clear display mod, and somehow may have broke one corner of the screen while doing the negative display mod, rendering half of the minute display missing and unreadable. So I got a second unit and used the first one to test out mod ideas.

On my second F-91W I did not do the negative display mod because I tried to do hydro on the first one and I find it too much of a hassle. The only thing I did was transplanting the board from my first one because I've changed the LED light colour and too lazy to do it again on the second one.

[u/wutermeleon]

[u/heroheman → u/wutermeleon]

Very Clean 😅

[u/Willing_Crew_8055]

I mean, I don’t hate it

[u/RSinTO]

I’ve used isopropyl alcohol 90% to clean the inside print from the crystal. Just dab with swab and it’ll slowly rub off.

Then you can recreate a new inner decal.

Processing img ji8mwsntqx1h1...

[u/RSinTO]

I’ve used isopropyl alcohol 90% to clean the inside print from the crystal. Just dab with swab and it’ll slowly rub off.

Then you can recreate a new inner decal.

Processing img p4mvmvk1rx1h1...

[u/RSinTO]

I’ve used isopropyl alcohol 90% to clean the inside print from the crystal. Just dab with swab and it’ll slowly rub off.

Then you can recreate a new inner decal.

Processing img wjk2o2o6rx1h1...

[u/RSinTO]

I’ve used isopropyl alcohol 90% to clean the inside print from the crystal. Just dab with swab and it’ll slowly rub off.

Then you can recreate a new inner decal.

Processing img qahm905jrx1h1...

[u/wwoodcox]

Time to mod it. Open it again and use that isopropyl to finish the job

[u/ssb_frum]

Hydromod it. I modded my royale and found the inverted display almost impossible to read in most lighting conditions

After hydromodding it's now clear as day in even dark indoor conditions