I recently acquired a new Seamaster 300M (the grey dial with the waves). Absolutely love the watch but I have noticed the AR coating is a little subject to scratches.

Is it frowned upon to polish off the exterior AR coating?

I know there are a number of posts related to if the AR scratches as well as various topics about “over polishing” of watches but I haven’t seen something related whether polishing the AR off is a good idea.

Thanks in advance!

 

Personal preference... I would wait until you’ve scratched it enough to where it really bothers you before removing it (it’s easy). Then you can decide which you like better: scratched AR or no AR. If you miss the AR, then have the crystal replaced.

In my case (x-33), I ended up preferring some AR over no AR

 

From someone who’s done it before, DONT DO IT! I regretted doing it so much, that I just ended up selling off the watch.

 

Why is that ? Didn't you manage to remove cleanly the external AR coating ?

 

Yes it came off just fine, but it completely changed the look of the watch. Negatively in my opinion. With a piece like the new SMP that has a lot of interesting details on the dial, I think the OP would definitely regret doing it.

I don’t know how much SMP crystals cost, but the PO ones are really expensive, and it wasn’t worth replacing it to me.

 

Would you happen to have before/after pics of polishing?

Thanks guys for the advice though! My plan is to probably leave it as is and maybe look at solutions when it needs a service (not for a number of years I hope). Unless it ends up looking really bad.

 

It’s hard to pick up the difference in pictures. I tried to look back but couldn’t find a photo to demonstrate the difference. To be honest, I don’t really know how to describe the difference either. Basically, if you like the disappearing crystal effect the AR provides, you’re not going to want to remove the coating. The coating under the crystal isn’t enough to give that effect.

 

Or why not have the 2xAR replaced? There are companies out there that can do it. The last one I had done a few years ago cost me about $100 - I had to get the crystal removed and refitted additional though.

 

The anti-reflective coating permits to see the dial with better image contrast. Dark features appear darker (as they should).

 

Not a faux pas at all. Many people do it and are very happy with the results after, and many people never wanted AR coating on the outside in the first place. It's a personal preference...

 

How do you remove the external AR coating cleanly ? I had a speedmaster saphir sandwich at one point and was pretty disappointed with the micro scratches on the AR and considered doing that.

 

I use diamond paste - 1 micron or 0.5 micron will take it off pretty easily.

 

Just my personal opinion, but for me the big selling point of this watch is the double AR and the way the crystal disappears. I'd go with some AR rather than none on the outside, and get the crystal changed on 1st service.

Are you sure it's not just some horrible sticky stain though? I had a similar 'scratch on my PO that went away after some really vigorous cleaning. I was certain it was a scratch I the AR and was pleasantly surprised.

 

It depends honestly, on double AR coated crystal removing the outer coating isn't ridiculously noticeable but it does change the look of the watch slightly. I have a SM300 that had a scratch across the AR coating, I managed to polish the scratch out with some polywatch and its looked fine ever since. Sadly, the watch is currently away for warranty work for a manufacturing issue with the coating on the barrels which is causing it to run inconsistently fast.

Edit: Literally just got a call from the OB that my watch is ready! THANKS OF!

 

Question for @Archer I have a3313 POC purchased new. It seems to be marketed as double AR, yet I see no blue sheen that is normally a sign of external AR, and you don’t seem to see problems with external AR on PO’s other then some references to early ones.

Do you know if it’s a higher end AR on those as they are marketed and priced above the SMP, or is it a single AR coating?

 

I like the effect of AR inside & outside the crystal in dressy watches, but I'm reluctant about having it on what was supposed to be tool watches.

The whole idea of sapphire being scratch free goes away when you apply AR coating in the *outside* of the crystal.

 

Specific reference number?

 

2918.50.38
222.30.38.50.01.002

Both are listed by Omega.

 

I never noticed a blue sheen on the two 8500 POs I had, but definitely notice it on the 2500 I have. I believe the AR coating was updated at some point and maybe you have the new coating?

 

2918.50.38 - two cases used for this reference:

055SU1781651 and 055SU1781653 - crystal for both is 062SB3063

222.30.38.50.01.002:

Case is 055SU5781655 - crystal is 062SB3090.

So in the part number for the crystal, there is a two letter code for the material - on all these that's SB.

SB - Sapphire antireflection multilayer 2 side

If I look at Work Instruction 61 (material codification) it lists several codes for sapphire crystals:

SA - Sapphire antireflection multilayer 2 side

SG - Sapphire antireflection monolayer 1 side

SG - Sapphire antireflection monolayer 2 side

SN - Sapphire natural

And an interesting one...

SV - Sapphire antireflection multilayer 2 side, outer side scratch proof

Just for the sake of it I used the reverse lookup feature t find all sapphire crystals with the code "SV" in them, which turned up a grand total of one crystal - for the Ploprof models.

And several others that define crystals with printing or colouring that don't apply to the watches in question.

Omega doesn't give any details on what the coatings are, but as noted by drhombus24, the tint of the coating has changed over the years, going from a purple tint to really no tint at all.

Cheers, Al