HOW to remove blue/purple-ish AR coating?

[Wiz]

what acid can you use and what strength or concentration? acetic acid or hydrochloric?

I think he is referring to hydrofluoridric acid.

A guy from an optical company told me it was used to remove AR coating from lenses untill maybe 20 years ago, but it's now forbidden (here at least, in less developped countries maybe you can still do it).

Be really carefull, though, this acid eats calcium, so basically is you put a drop on your skin it can dig all the way thought the bones. It's very dangerous, and therefore restricted in most countries.

 

[rbj69]

what acid can you use and what strength or concentration? acetic acid or hydrochloric?[/QUOT

i would not use acid at home ,, lots can go wrong :facepalm:

rbj69

btw use a buffing wheel on a coarse cloth wheel u can get it at lowes , a yellow looking wheel ,, and use a coarse rouge but it will get hot in your hands and it takes time to get it all off ,, do a section at a time ,, different ar coatings take longer than others

 

[Edwinowl]

Must admit I have a Tag Pendulum which has a significant blueish tinge. Does anyone do that type of work anyone know? i e wizz.

 

[trailboss99]

I think he is referring to hydrofluoridric acid.

A guy from an optical company told me it was used to remove AR coating from lenses untill maybe 20 years ago, but it's now forbidden (here at least, in less developped countries maybe you can still do it).

Be really carefull, though, this acid eats calcium, so basically is you put a drop on your skin it can dig all the way thought the bones. It's very dangerous, and therefore restricted in most countries.

Ah yes, HF acid is NOT something to use at home, it makes hydrochloric look like something you would give to a 5yo (or txrob even) to play with.

 

[Atticus]

I want to remove mine as well but my only watch tool is a pair of screwdrivers and some duck tape LOL..... Is it that hard to remove the movement?

 

[baereli]

How can I find out if the glass is saphire cristal or mineral?

 

[Wiz]

How can I find out if the glass is saphire cristal or mineral?

This have been discussed many times, you can find the answer on the forum.

 

[DreambreaX]

Cape Cod will not damage sapphire crystal. Another alternative is dremel with polishing paste. Sapphire is really hard, so it allows a lot of room for polishing products to remove AR coatings.

Another method is: use strong acid, but you need to have license and proper lab to do it.

Takashi, I buy hublot big bang 44mm, I want to remove the bluish tint sapphire crystal, can you help me??

 

[bc1221]

I have removed AR coatings off of many watches but I’ve run in to some weird shit

Omega SMPc. The AR inside was scratched up pretty bad. (It was shipped with screws inside the case. )

I got most of it off with polishing paste, dremel and 1500 grit sandpaper.

I noticed a little spot layer that I’d missed so I went through the same steps. Now there’s hairline scratches all over the crystal. When I try the sand it off, nothing. When I try to add more scratches to see if it’s mineral crystal, nothing.

I’m so confused as to what the hell crystal this thing is... Im planning on just buying a gen crystal now but have any of you run in to this before? It’s just odd.


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[Tweetybird87]

where do you guys source replacement crystals from?