I think I might line the V with some felt or something to keep from scratching the lens elements, but it's just a guess since I've never done this type of repair.
Some UV cure glue would be great for this, all you would need to to is take it out in the sunshine to cure it.
UV cure cement would be better, or you could just use Canada Balsam again. CB is a slow cure cement, UV cure is A. fast, and B, PERMANENT. Ie, mess up the alignment and it will stay that way. Also, look for scribe marks on the edges of the element before you solvent soak them. It's not uncommon for them to be there to mark proper alignment of the doublet before it is cemented. If there aren't any, mark the edges so you can put them back in alignment. Also check if the two lenses are in cylindrical alignment. They might have been cemented off axis to make them align optically, or maybe they were ground to form a cylinder after being cemented which may have removed the scribe marks.
Sunshine I usually have plenty of, even in the winter, down here in Houston. Watch, though, when I finally try to do this, we'll have a week's worth of rain. :rolleyes: But then I remind myself that UV rays pass through clouds. I'll be more concerned about temperature, though. Most glues I work with don't like it when temps fall below 50F.
Originally Posted by Greg_E
Not to worry about scratches. The wood should contact only the edges of the elements, and besides, glass is a lot harder than wood anyway. I've got a lot of Spanish cedar scrap -- it's a hardwood, technically, but almost as soft as pine. Should work okay, I'm thinking.
Bob, thanks for the scribe mark tips. I'll be sure to look for any. Interesting -- I ran across an optic once that appeared to have been cemented off-axis. Now I know why!
That's exactly what I meant by "V" clamps. They don't have to be anything fancy, ply or pine works fine. It just has to be thick enough to keep both pieces aligned not to apply pressure of more than a couple of ounces. I just us small clamps with the squeeze trigger.
I should have mentioned that when I have the elements together I do apply pressure with my fingers initially for a firm bond.
Make sure there's no residue from the cement on the surfaces of the glass. If you use the UV stuff it's imf**king possible to get off.
Heavily sedated for your protection.
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I received an email today from John Van Stelten over at Focal Point. Cost to re-cement my doublet will be somewhere in the neighborhood between $195-250. I'm sure they do top-notch work, but that's quite a bit more than I paid for the lens, so I reckon I'll give it a go myself.
BTW, I was reviewing the instructions over at Summers for their various UV cements, and they recommend the use of a 365nm wavelength black light for best results. I'm wondering if regular old sunlight might suffice? It's bound to have a 365nm component.
You might try Camtech Photographic Services
They will do a great job at much less than your other quote ( not to mention your dollar will go a long way up here again)
They did my first Wolensak lens that was totally separated and it is fantastic. Give them an email. Can't hurt
"There are a great many things I am in doubt about at the moment, and I should consider myself favoured if you would kindly enlighten me. Signed, Doubtful, off to Canada." (BJP 1914).
Sunlight works just fine.
Sometimes the engineers at Summers and just too specific. For fine, highly critical work you may need that kind of specificity. 90% of the time ,,,,NOT! Kinda like the argument that you need a collimator to reassemble or focus a lens.
The standards to which equipment is made both recently and not so recently make alignment errors pretty negligible. Unless you're the guy that uses test charts and microscopes.
Heavily sedated for your protection.
They are in Croydon, south London, England.
Last edited by Windscale; 02-10-2009 at 11:37 AM. Click to view previous post history.
Good morning, Windscale;
A quick request for a confirmation of an old memory:
Isn't Croydon on the A-26 south "of" London? Or has London grown that far south now?
Ralph Javins, Latte Land, Washington
When they ask you; "How many Mega Pixels you got in your camera?"
just tell them; "I use activated silver bromide crystals tor my image storage media."