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any reasonable coating service or solution?
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PostPosted: Mon Dec 14, 2015 7:11 am    Post subject: any reasonable coating service or solution? Reply with quote
Over the years I have accumulated quite a number of lenses that would greatly benefit if they had a coating, usually of just one element of even only one surface, repaired resp. replaced. I believe there are some services out there that do coating but which generally, for repairing other than very valuable lenses, are not recommended simply because they are expensive.

- I wonder if there hasn't come up an economical alternative e.g. out of China. Or if there even is any DIY solution just using a spray or something alike, given that it won't be a perfect solution but enough to improve a lens of which the coating already had been removed.

any info anyone?


PostPosted: Mon Dec 14, 2015 8:28 am    Post subject: Reply with quote
A DIY solution isn't going to work. the thickness of the coating is critical in getting it to work & has to be controlled to very precise tolerances.


PostPosted: Mon Dec 14, 2015 9:12 am    Post subject: Reply with quote
There is polishing and coating service in China for much less but I would suggest you leave it as it. The lens may need to be polished before re-coating and there is risk of breaking the glass. All the cemented elements are not recommended for re-coating.


PostPosted: Mon Dec 14, 2015 10:09 am    Post subject: Reply with quote
thank you very much for your answers

calvin83 wrote:
There is polishing and coating service in China for much less but I would suggest you leave it as it. The lens may need to be polished before re-coating and there is risk of breaking the glass. All the cemented elements are not recommended for re-coating.


hm Calvin, for me this still is great news, and I really would love to get the contact info for that service! In case they don't converse in English I may evenask for further help from you, Calvin Embarassed

- the lens that could benefit most from re-coating is an M-Rokkor 2.8/28 that had the known 'white spots', they had gone beyond the rim and had corrupted the coating on the whole surface. It was rather unusable as it was, I took the effort and had removed / polished that bad coating already. Sharpness is much improved, but it glows badly and remains rather unusable. That is polishing already is done, and if it really broke it just would remain unusable.. Well, I have seen the same lens with the fault as bad as mine selling for 250 to 300 usd, and after my polishing it even looks clean, but I would not want to cheat anybody and as it is and declaring it's state truthfully it hardly is of much value.
Same situation with at least one more lens, and I have a few Canon LTMs with hazy element, one already polished, some 3 or 4 others not yet, but again, as is they hardly have value, as I see it they all only could benefit


PostPosted: Mon Dec 14, 2015 10:29 am    Post subject: Reply with quote
I had a source in Russia, but they stopped doing that. Not cheap though it was.

There is a seller "prolenscla" on ebay from Taiwan who offers those services incl. re-cementing: http://www.ebay.com/usr/prolenscla?_trksid=p2047675.l2559
Quote him: "Charge for lens group separation re-cementing treatment and damaged coating polishing treatment starting from US$ 150.
The actual charge depend on which kind of the lens and the size of the lens need to repair. It is necessary to negotiate between you
and me before sending me your lens." So I estimate it to be quite more actually... Wink

On his FB site https://www.facebook.com/CLAmanualfocuslens he shows some impressive results, I must admit.





P.S.: I added this info to a Sticky here


PostPosted: Mon Dec 14, 2015 10:46 am    Post subject: Reply with quote
looks impressive, but I am looking for a service that is way cheaper, actually.
And Calvin, I am thinking of not sending in the whole lens but the single elements that have to be treated only, some polishing + coating, some coating only. Actually I'd also have cemented double elements that would need re-cementing, in case I do get the service in China you know to do some work for me, do you know if they also do re-cementing?


PostPosted: Mon Dec 14, 2015 11:18 am    Post subject: Reply with quote
kuuan wrote:
looks impressive, but I am looking for a service that is way cheaper, actually.
And Calvin, I am thinking of not sending in the whole lens but the single elements that have to be treated only, some polishing + coating, some coating only. Actually I'd also have cemented double elements that would need re-cementing, in case I do get the service in China you know to do some work for me, do you know if they also do re-cementing?


Yeah, but then the clock rings and we wake up - bummer really! Wink Wink Wink


PostPosted: Mon Dec 14, 2015 11:28 am    Post subject: Reply with quote
no worries and Klaus I am very good in making dreams come true, don't do much else, really Smile


PostPosted: Mon Dec 14, 2015 12:28 pm    Post subject: Reply with quote
For re-cementing, you can do it yourself with UV cement if you have the patent. The most difficult part is not gluing the elements but to separate them. My friends do it on their own too. If you want to align the elements more perfectly(for wide angle to short tele lens), you will need a device for collimation(workshops who made glasses should have one). Long focal length lenses are usually less prone to small misalignment except mirror lenses.

BTW, I heard some negative feedback from some local guys on the service mentioned above in Taiwan. There will be always some risk performing such repair.

Last edited by calvin83 on Tue Dec 15, 2015 12:24 pm; edited 1 time in total


PostPosted: Mon Dec 14, 2015 12:34 pm    Post subject: Reply with quote
my first trial to separate two elements had failed, nothing broken, but I just couldn't get them apart. - haven't given up yet Smile


PostPosted: Mon Dec 14, 2015 1:18 pm    Post subject: Reply with quote
One of the most safe way is to heat the element in oven slowly until you see there is change in the cement.


PostPosted: Mon Dec 14, 2015 1:53 pm    Post subject: Reply with quote
calvin83 wrote:
One of the most safe way is to heat the element in oven slowly until you see there is change in the cement.


thank you Calvin. My next trial shall be in an oven. My first, failed trial was placing it on top of a 100W lamp, or was it a 60W only? Anyway, heat seemed not have been high enough. Or it's a cementing that won't bulge? It is from a CV Heliar LTM 2.5/75, not a very 'old' lens.


PostPosted: Mon Dec 14, 2015 2:18 pm    Post subject: Reply with quote
It might have been cemented using UV cemented, hardened by UV light.
This can't be seperated by your method.


PostPosted: Mon Dec 14, 2015 2:43 pm    Post subject: Reply with quote
kds315* wrote:
It might have been cemented using UV cemented, hardened by UV light.
This can't be seperated by your method.

This may help but need to be careful with the chemicals.
http://www.dymax.com/images/pdf/literature/lit079_removal_of_cured_uv_adhesives_tb.pdf


PostPosted: Mon Dec 14, 2015 3:03 pm    Post subject: Reply with quote
Klaus thank's, I am afraid that this might be the case
Calvin wow, a bit frightening but great information, thank you so much for that!


PostPosted: Mon Dec 14, 2015 3:03 pm    Post subject: Reply with quote
calvin83 wrote:
kds315* wrote:
It might have been cemented using UV cemented, hardened by UV light.
This can't be seperated by your method.

This may help but need to be careful with the chemicals.
http://www.dymax.com/images/pdf/literature/lit079_removal_of_cured_uv_adhesives_tb.pdf


Yes, indeed, and I would propose to only have experienced personnel do this!


PostPosted: Mon Dec 14, 2015 10:04 pm    Post subject: Reply with quote
calvin83 wrote:
kds315* wrote:
It might have been cemented using UV cemented, hardened by UV light.
This can't be seperated by your method.

This may help but need to be careful with the chemicals.
http://www.dymax.com/images/pdf/literature/lit079_removal_of_cured_uv_adhesives_tb.pdf


MEK, mentioned in the data sheet, is easily available from most plumbing and building merchants as it is the solvent used to clean PVC pipework before gluing. Be very careful, it is very nasty stuff. Not only to the user, it will strip paint.


PostPosted: Sun Dec 20, 2015 6:49 am    Post subject: Reply with quote
kuuan wrote:
...

- the lens that could benefit most from re-coating is an M-Rokkor 2.8/28 that had the known 'white spots', they had gone beyond the rim and had corrupted the coating on the whole surface. It was rather unusable as it was, I took the effort and had removed / polished that bad coating already. Sharpness is much improved, but it glows badly and remains rather unusable...


to put the record straight: By now, without re-coating, my M-Rokkor 2.8/28 is performing quite well. Clarity and sharpness had been improved decisively after polishing, now finally I repainted the outer rim of the lens more thoroughly and that strongly reduced blooming.
I believe that it may still bloom a bit more than a perfect copy should and that it would benefit from re-coating, but it has become quite usable again, see: http://forum.mflenses.com/viewtopic,p,1461435.html#1461435
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