Page 3 of 3 FirstFirst 123
Results 21 to 30 of 30

Thread: Source for custom-made ground glass?

  1. #21

    Join Date
    Sep 1998
    Location
    Loganville , GA
    Posts
    14,409

    Re: Source for custom-made ground glass?

    Quote Originally Posted by Nodda Duma View Post
    You’d have to ask them.

    Btw borosilicate isn’t the same as Pyrex. Pyrex is just one form (Corning’s version, to be absolutely correct) of several different makeups. Sort of like there are many different 100 speed B&W films.
    From Wikipedia:


    Open main menu
    Wikipedia
    EditWatch this pageRead in another language
    Borosilicate glass

    Guitar slide made of borosilicate glass
    Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (~3 × 10−6 K−1 at 20 °C), making them resistant to thermal shock, more so than any other common glass. Such glass is less subject to thermal stress and is commonly used for the construction of reagent bottles. Borosilicate glass is sold under such trade names as Borcam, Borosil, DURAN, Suprax, Simax, BSA 60, BSC 51 (By NIPRO), Heatex, Endural, Schott, Refmex, Kimble, MG(India) and some (but not all) items sold under the trade name Pyrex.

    Contents
    History Edit

    Borosilicate glass was first developed by the German glassmaker Otto Schott in the late 19th century. Otto Schott was also the founder of today's Schott AG, which has sold borosilicate glass later under the brand name DURAN. As part of an equity carve-out in 2005, the DURAN Group was founded and the manufacture of Duran was transferred to it. After Corning Glass Works introduced Pyrex in 1915, the name became a synonym for borosilicate glass in the English-speaking world. However, borosilicate glass is the name of a glass family with various members tailored to completely different purposes. Most common today is borosilicate 3.3 glass such as Duran, International Cookware's Pyrex, NIPRO BSA 60, and BSC 51.

    The European manufacturer of Pyrex, International Cookware, still uses borosilicate glass in its Pyrex glass kitchen products,[1] but the U.S. manufacturer of Pyrex kitchenware now uses tempered soda-lime glass.[2] Thus Pyrex can refer to either soda-lime glass or borosilicate glass when discussing kitchen glassware, while Pyrex, Bomex, Duran, TGI and Simax all refer to borosilicate glass when discussing laboratory glassware. The real difference is the trademark and the company that owns the Pyrex name. The original Corning ware made of borosilicate glass was trademarked in capital letters (PYREX). When the kitchenware division was sold, the trademark was changed to lowercase (pyrex) and switched to low thermal-expansion soda-lime glass. The scientific division of Pyrex has always used borosilicate glass[3].[citation needed]

    In addition to quartz, sodium carbonate, and aluminium oxide traditionally used in glassmaking, boron is used in the manufacture of borosilicate glass. The composition of low-expansion borosilicate glass, such as those laboratory glasses mentioned above, is approximately 80% silica, 13% boric oxide, 4% sodium oxide and 2–3% aluminium oxide. Though more difficult to make than traditional glass due to the high melting temperature required, it is economical to produce. Its superior durability, chemical and heat resistance finds use in chemical laboratory equipment, cookware, lighting, and in certain kinds of windows.”

    How does the extra cost benefit a ground glass focusing screen?

  2. #22
    Nodda Duma's Avatar
    Join Date
    Nov 2014
    Location
    Batesville, Arkansas
    Posts
    1,116

    Source for custom-made ground glass?

    Ok Bob, you win. You can keep on arguing whatever point you’re trying to make. I’ll just keep drinking my beer I have here.
    Newly made large format dry plates available! Look:
    https://www.pictoriographica.com

  3. #23
    Drew Wiley
    Join Date
    Sep 2008
    Location
    SF Bay area, CA
    Posts
    18,338

    Re: Source for custom-made ground glass?

    Convenience of grinding might have something to do with it. Sinar and other big companies had to do it in volume, presumably automated in some manner. Cutting harder or tempered glasses is also trickier and would have to factor into cost, plus the outrageous predictable markup such companies once expected to get for replacement components. In this respect, the need for volume production would probably have dictated choices. Or maybe they just had an inside deal with a particular glass distributor. I dunno. But they weren't either a charity or somebody with a moonlight business in their garage who sold direct to the end user. Sinar glass is only slightly different functionally than Satin Snow, but I actually prefer the latter. Haven't tried cooking on either!

  4. #24

    Join Date
    Sep 1998
    Location
    Loganville , GA
    Posts
    14,409

    Re: Source for custom-made ground glass?

    Quote Originally Posted by Drew Wiley View Post
    Convenience of grinding might have something to do with it. Sinar and other big companies had to do it in volume, presumably automated in some manner. Cutting harder or tempered glasses is also trickier and would have to factor into cost, plus the outrageous predictable markup such companies once expected to get for replacement components. In this respect, the need for volume production would probably have dictated choices. Or maybe they just had an inside deal with a particular glass distributor. I dunno. But they weren't either a charity or somebody with a moonlight business in their garage who sold direct to the end user. Sinar glass is only slightly different functionally than Satin Snow, but I actually prefer the latter. Haven't tried cooking on either!
    Drew, most camera manufacturers don’t grind their glass, they buy it, as they do many other components of their finished product.

    Linhof does not make the castings for their bodies, they finish the castings that are supplied by their sub suppliers. Before the law suit Linhof made parts for Sinar.

    So, if this gg material is so superior the camera manufacturers could have just as easily supplied it.

    As an example, Minolta developed a very bright and contrasty glass that they sold to both Hasselblad and Rollei for their 6x6 SLR cameras. Both companies put their own name on it and sold them as an accessory at a much higher cost.
    There is no reason why this could not be done by the large format companies if this type of gg is truly superior.

    Fresnel Optics made a tidy amount selling enhanced systems under their subsidiery, Beattie- as the Beattie Screen; by us as the Super Screen and by other companies offering a Fresnel screen with a frosted focusing surface on one side.

    But the major camera manufacturers did not offer these systems, why?

  5. #25

    Join Date
    Sep 1998
    Location
    Loganville , GA
    Posts
    14,409

    Re: Source for custom-made ground glass?

    Quote Originally Posted by Nodda Duma View Post
    Ok Bob, you win. You can keep on arguing whatever point you’re trying to make. I’ll just keep drinking my beer I have here.
    I’m not trying to argue with you, but I don’t see your point! Better color is nonsense since the vast majority of color shot on view cameras have always delivered what the shooter needed without exotic glass types! Especially ground glasses supplied on cameras for the past couple of decades.

  6. #26
    Drew Wiley
    Join Date
    Sep 2008
    Location
    SF Bay area, CA
    Posts
    18,338

    Re: Source for custom-made ground glass?

    Bob, I have no idea why Sinar discontinued their wonderful Norma tapered bellows and replaced it with the less versatile, greater-flare box 4x5 bellows, except for one obvious reason - cost. Make a bellows a mile long and slice it up as needed ... way more cost effective than the first version. I even have a 28 inch Horseman box bellows that fits Sinar. Wonder if I'll ever use it again, since I've given myself a Norma with two mint tapered bellows for a retirement present. But Sinar ground glass is rather hard and brittle. I've had to grind rather than cut it down to size to fit non-Sinar backs. And I have gear to otherwise
    cut tempered glass.

  7. #27
    Mike in NY's Avatar
    Join Date
    Sep 2012
    Location
    Hudson Valley, NY
    Posts
    220

    Re: Source for custom-made ground glass?

    I agree with others; making your own gg is pretty straightforward. I'm so accustomed to cutting glass for my wet plates, and sanding my 19th century furniture reproductions, that making my gg was easy the first time I tried it. I have to admit, though, that buying is also pretty expedient, and you'll know it's ground properly.
    I dream in black and white.

  8. #28
    Mike in NY's Avatar
    Join Date
    Sep 2012
    Location
    Hudson Valley, NY
    Posts
    220

    Re: Source for custom-made ground glass?

    Quote Originally Posted by Nodda Duma View Post
    Ok Bob, you win. You can keep on arguing whatever point you’re trying to make. I’ll just keep drinking my beer I have here.
    Pass me one, will ya?
    I dream in black and white.

  9. #29
    In the desert...
    Join Date
    Oct 2006
    Location
    Nevada/N.Arizona/ Florida Keys
    Posts
    613

    Re: Source for custom-made ground glass?

    Hopf made a beautiful 5x7 for my Dorf

  10. #30
    Jac@stafford.net's Avatar
    Join Date
    Dec 2012
    Location
    Winona, Minnesota
    Posts
    5,413

    Re: Source for custom-made ground glass?

    What size GG do you need? Place a Want to Buy in the appropriate sub-forum and I think you will be happy.

Similar Threads

  1. Replies: 11
    Last Post: 17-Dec-2015, 23:22
  2. 8x10 Ground Glass source?
    By ggbushaw in forum Cameras & Camera Accessories
    Replies: 5
    Last Post: 10-May-2007, 09:00
  3. Source for ULF Ground Glass
    By Michael Kadillak in forum Cameras & Camera Accessories
    Replies: 6
    Last Post: 23-Jul-2004, 11:03
  4. ground glass source
    By Carl Weese in forum Gear
    Replies: 8
    Last Post: 20-Dec-2001, 13:30

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •