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Tom1956
07-26-2013, 05:23 PM
This 1943 patent on the subject of lens coating is interesting. Franly I think any such idea would be biting off more than I could chew, but nonetheless it is certainly interesting.
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0CEQQFjAE&url=http%3A%2F%2Fwww.google.fr%2Fpatents%2Fdownloa d%2F2410720_LENS_COATING_APPARATUS.pdf%3Fid%3DxgQa AAAAEBAJ%26output%3Dpdf%26sig%3DACfU3U2VvQXcPHOLky QdOKUmXtbaAoKIXA%26source%3Dgbs_overview_r%26cad%3 D0&ei=FfTyUdWoO5Kj4AOyxIHwAQ&usg=AFQjCNHgWiMSEsZkiSAfKYDOr8djQSlNrA&sig2=1y83LuBq3ZMmIFTCnj6Pcg

lxdude
07-26-2013, 05:55 PM
Ya'll just need a laser to heat it, that's all.:happy: ;)

Tom1956
07-26-2013, 09:49 PM
Seriously, I would think that google searches on the subject of DIY lens coating would probably turn up my handle in conjunction with the subject; now, and at earlier dates. I was bound to purssue this matter to a reasonable conclusion in my own mind. I believe it can be done, but I also believe that it is also a good way to die as a pauper from spending too much of one's life on such hobbies. In our lives, time is money, and like it or not the best way is still to send the lens off to the big boys who do this sort of thing for a living. Even if someone like me was successful in this wheel re-invention, there is still the matter of the experience. Like any technical field, experience only comes with years. So now I can comfortably close the matter. Thanks, guys.

lxdude
07-26-2013, 10:11 PM
If you have really old glass, you could artificially age it chemically, as the first attempts at anti-reflection coating were done, after it was observed that glass which had formed a tarnish had better transmission and contrast.
That could be fun, with no big investment.

illumiquest
07-26-2013, 10:49 PM
I really don't want to coat the glass. I want to get rid of polish marks and signs of 165 years of use...

mike c
07-26-2013, 11:05 PM
That Liquid Lens stuff sounds pretty good, if its an old uncoated lens it should not cause much harm.

Mike

Tom1956
07-26-2013, 11:21 PM
illumiquest, sorry for hijacking your thread. I had already deemed your question as answered in post #6, if you follow off on some searches concerning the items mentioned. Seems quite feasible, as compared to my pursuit.

Steve Smith
07-27-2013, 02:57 AM
You need to make a pitch lap and try cerium oxide as a polishing agent.

Would jewellers' rouge work as well?

I have a lens which I want to remove the coating from rather than re-polish the glass. It has been seriously over polished in a past life and only has about 75% of its coating left.

I'm thinking that I have nothing to lose in trying!


Steve.

richard ide
07-27-2013, 06:56 AM
Steve,
I have about five grades of rouge in my workshop. I do not think any are fine enough for that purpose. Abrasives for optical use have the particle size very carefully controlled.

E. von Hoegh
07-29-2013, 08:38 AM
If you have really old glass, you could artificially age it chemically, as the first attempts at anti-reflection coating were done, after it was observed that glass which had formed a tarnish had better transmission and contrast.
That could be fun, with no big investment.

I have a 6" Dagor from ca. 1906-8, it has an absolutely beautiful and uniform deep blue bloom on the front and rear external surfaces. Sadly it has no bloom inside, where it would do the most good.

lxdude
07-29-2013, 05:29 PM
I wonder what actually creates that bloom- oxygen, atmospheric contaminants of some type?

E. von Hoegh
07-30-2013, 01:08 PM
I wonder what actually creates that bloom- oxygen, atmospheric contaminants of some type?

I've always seen it referred to as oxidation.
There were many attempts to produce said bloom under controlled conditions, none of which was very successful. Perhaps it just takes place so slowly that none of the processes were commercially valuable. The lens I referred to has been in my possession since the late 1980s, and it was well bloomed when it came to me.

Farside
08-21-2013, 06:43 PM
Lend it to a smoker for a few years.
As a previously heavy smoker I can vouch for the film that forms on window glass and anything else in the room.
To lend some credence to this notion, bear in mind the atmosphere in times past, especially in cities, was generally more heavily contaminated than we're used to now. Indoors; smokers, open fires, stoves, ranges, the general fug of living without adequate ventilation. Outdoors; plenty of smog, soots, industrial air pollution of many types.