Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,830   Posts: 1,582,269   Online: 988
      
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 25
  1. #11

    Join Date
    May 2006
    Shooter
    Medium Format
    Posts
    775
    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.

  2. #12

    Join Date
    Feb 2008
    Location
    Winnipeg, Canada
    Shooter
    Multi Format
    Posts
    1,301
    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.

  3. #13
    Phil's Avatar
    Join Date
    Sep 2002
    Location
    Vermont
    Shooter
    8x10 Format
    Posts
    115
    Images
    4
    Surplus Shed has chunks of 'Canada Balsam':

    http://www.surplusshed.com/pages/item/b1077.html

  4. #14
    cooltouch's Avatar
    Join Date
    Jan 2009
    Location
    Houston, Texas
    Shooter
    Multi Format
    Posts
    340
    Quote Originally Posted by Greg_E View Post
    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.
    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.

    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!

    Best,

    Michael

  5. #15

    Join Date
    Apr 2004
    Location
    Montgomery, Il/USA
    Shooter
    Multi Format
    Posts
    5,300
    Michael,
    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.

  6. #16
    cooltouch's Avatar
    Join Date
    Jan 2009
    Location
    Houston, Texas
    Shooter
    Multi Format
    Posts
    340
    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.

    Best,

    Michael

  7. #17

    Join Date
    Aug 2006
    Location
    Hamilton, Ont, Canada
    Shooter
    Large Format
    Posts
    1,083
    You might try Camtech Photographic Services
    http://www.camtechphoto.com/
    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).

    Regards
    Bill

  8. #18

    Join Date
    Apr 2004
    Location
    Montgomery, Il/USA
    Shooter
    Multi Format
    Posts
    5,300
    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.

  9. #19

    Join Date
    Jun 2008
    Shooter
    Medium Format
    Posts
    76
    http://optil.co.uk/

    They are in Croydon, south London, England.
    Last edited by Windscale; 02-10-2009 at 11:37 AM. Click to view previous post history.

  10. #20
    Ralph Javins's Avatar
    Join Date
    Jul 2008
    Location
    Latte Land, Washington
    Shooter
    Multi Format
    Posts
    832
    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?
    Enjoy;

    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."

Page 2 of 3 FirstFirst 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin