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Posted

Help please. Discovered a small scratch approx. 4.5mm long at the 12:00 position on the crystal that I could feel with a finger nail. I tried to remove it with a dremel and felt polishing tip with a dab of polishing compound but only made it worse. So I am now in search of a replacement crystal. Your help with a link is appreciated. Movement is 5110. Watch is WVA-M650D- 1A2JF. I would consider sapphire if it's not unreasonably priced.

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Posted

Looks like it's a flat crystal, so you can use a generic. I suggest that you bring it to a good watch shop (where they change batteries and do minor repairs) for replacement. They will measure it and if they can't, you can order one yourself for about $1. Sapphire can be around 10 - 15.

Posted

Crystal measures 34mm installed. Ordered a watch press set from ebay. Youtube videos show careful removal and replacement looks straight forward. I'd like to do this myself. But need to know where to order the crystal once I remove and measure it.

Posted

Cousins UK, for example. Has most of the sizes for glass and sapphire. Someone has posted that Ebay has even more choices in thickness for sapphire.

Posted

Cousins UK ships worldwide at very reasonable prices. I have no ranking for US Ebay sellers, you can look at their feedback.

Posted

Thanks I will register with them and order one of their generic flat sapphires after I remove this old one. Not sure of the size yet but I see I can get a 34.1 x 1.0mm sapphire crystal for approx. $27 US plus shipping. Sounds like the plan.

Posted

Meanwhile, I have been rubbing the damaged area of the crystal with a q-tip and a dab of .5 micron diamond paste. It doesn't look nearly as bad now.

Posted

Ordered a 34 x 1 mm flat sapphire from Esslinger. They are fairly close to me right across Lake Michigan. Should have it within the week. Will post again after install.

 

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Posted
Ordered a 34 x 1 mm flat sapphire from Esslinger. They are fairly close to me right across Lake Michigan. Should have it within the week. Will post again after install.
 
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They already shipped! That was quick within an hour of placing the order. Regardless the damaged crystal is rather inconspicuous now. And you have to hold it at a certain angle to really see it. But I know it's there. So I'll change it.
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Posted

The sapphire crystal arrived and I must say I'm am not all that impressed with it. It just a flat piece of blah glass. The original mineral glass has a very slight curve to it. So I decided to try rubbing a bit more with that diamond paste. Went by hand using q-tip, paper towel and a few dabs of the heavier 28 micron stuff. It took several hours of hard rubbing but now all the scratches are gone and that depression in the center is just barely felt. Followed up with some finer grades and used .5 micron as a final polish. I'm happy with this and am thinking about not changing the crystal after all.

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Posted
4 hours ago, Dweib said:

It took several hours of hard rubbing but now all the scratches are gone  

Which is why using a rotary tool on a felt wheel is advisable.

Posted
Which is why using a rotary tool on a felt wheel is advisable.

Not if your in-experienced doing so. The reason it took several hours of hard rubbing was not for the original scratch (easily removed several days ago) but for removing the dimples and marks caused by improper use of the rotary tool and felt wheel. I tried the dremel method twice as shown in the esslinger and other videos and both times I apparently applied too much pressure with not enough movement and the friction overheated the wheel on the crystal causing a dimple and tiny score marks. Suggest recommending novices practice the technique on something other than a good watch first.

 

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Posted
48 minutes ago, Dweib said:

I tried the dremel method twice as shown in the esslinger and other videos and both times I apparently applied too much pressure with not enough movement and the friction overheated the wheel on the crystal causing a dimple and tiny score marks.

I think you were spinning the dremel too fast. In fact, these starting at 3,000 rpm are already too fast for polishing, not too mention buffing. A regular drill actually works better.

Quote

Suggest recommending novices practice the technique on something other than a good watch first.

It's always good to learn on a throw away watch. Just like paying attention to what one is doing, and not blame others for own's failures. 

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Posted
It's always good to learn on a throw away watch. Just like paying attention to what one is doing, and not blame others for own's failures. 


Agreed. I have an old '70's Timex that's pretty scratched up. I'll see what I can do. But I believe it's an acrylic crystal so I wonder if a rotary tool would be appropriate?

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Posted
55 minutes ago, Dweib said:

 


Agreed. I have an old '70's Timex that's pretty scratched up. I'll see what I can do. But I believe it's an acrylic crystal so I wonder if a rotary tool would be appropriate?

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It's very easy to over do and overheat acrylic with a rotary tool. If I'm going to bother polishing plastic, I do it by hand. Mostly I just replace acrylic, I have a good inventory of round crystals and huge piles of various specialized plastic crystals for vintage watches. Then it becomes a matter of digging through the mountain for the right one :-)

Posted
It's very easy to over do and overheat acrylic with a rotary tool. If I'm going to bother polishing plastic, I do it by hand. Mostly I just replace acrylic, I have a good inventory of round crystals and huge piles of various specialized plastic crystals for vintage watches. Then it becomes a matter of digging through the mountain for the right one :-)

Ah.. makes me wonder if the crystal I've been working on above is actually acrylic. Kinda feels like plastic.

 

I may contact you if the old Timex needs a new one.

 

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Posted
1 hour ago, Dweib said:

Agreed. I have an old '70's Timex that's pretty scratched up. I'll see what I can do. But I believe it's an acrylic crystal so I wonder if a rotary tool would be appropriate?

No it's not, as mentioned crystal would overheat immediately and be ruined. Isn't even necessary to use diamond paste with these, any fine abrasive compound will work. 

Posted

Yeah, I love this watch and won't give it up for nothin'. Perfect size, full featured, light weight, solar powered, syncs every night at 12:04, easy to read digital stop watch, secondary time set to Greenwich UTC, 5 alarms, has a light but the lume is bright and easily visible all night long clear to my alarm time of 5:45. WVA-M650D-1A2JF
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Posted (edited)

At this angle you can clearly see the dimple that is still in the crystal. But it's usually not very noticeable. And not seen in the last two pics above. So I won't change it just yet. Dimple was caused by improper use of a dremel and polishing wheel.
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Edited by Dweib
  • 2 weeks later...
Posted

I want to know why the devil this $200 watch scratched so easily. I've been wearing a cheap $40 K&S autowind at my machinist job for several months and not get a scratch on it but the moment I wear this Casio for just one day the crystal scratches up?

Posted

My bet is that is is not mineral glass, but some sort of hard acrylic. A dremel won't dimple mineral glass that quick. I've polished several old mineral glass crystals (pocket watch size) with a dremel and never made a mark like that, and if it scratches that easily, it also makes me lean towards some sort of acrylic.

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Posted
My bet is that is is not mineral glass, but some sort of hard acrylic. A dremel won't dimple mineral glass that quick. I've polished several old mineral glass crystals (pocket watch size) with a dremel and never made a mark like that, and if it scratches that easily, it also makes me lean towards some sort of acrylic.

I agree with you. That is my opinion as well. Although the specs claim mineral glass.

 

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