how to make ground glass ??

Discussion in 'Camera Building, Repairs & Modification' started by nick mulder, Aug 29, 2005.

  1. nick mulder

    nick mulder Subscriber

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    okidoki,

    couldn't find this in a search - but how does one grind glass into the 'ground glass' finish ?

    I have a piece of 2mm glass I want to make into a 4x5 back - how do I sand it ? is it just as simple as fine sand paper ?

    if not what is the best technique ?

    thanks
     
  2. Dave Parker

    Dave Parker Inactive

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    The most common method is sandblasting, although this will produce a rough ground glass screen, it will be servicable..or many have used gease based valve grinding compounds normally found at auto repair shops, normally, using sandpaper is not to sucessfull. Another method is to make a table to hold the glass that randomly moves up down and in a occilating pattern then add metal ball bearings and leave it run for about 24 hours, of course you can stop by your local hobby shop and pick up some acid, like they use to acid etch patterns on wine glasses and then coat one side and then wash off and repeat until you get an even etch

    Good luck on your project.

    Dave Parker
    Satin Snow Ground Glass
     
  3. Bruce Osgood

    Bruce Osgood Membership Council Council

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    The BEST technique, the absolute BEST is contact Dave Parker at Satinsnow. If you are in need of a GG you won't do better. If you just want to scratch up some glass see the previous thread.
     
  4. Jon Shiu

    Jon Shiu Subscriber

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    Hi, this was mentioned in another thread. The technique was described in Photo Techniques magazine by Dick Dokas several years ago. He uses aluminum oxide to grind with. Don't know if Dave uses this method or not, since he didn't mention it. The article is here:
    http://www.dokasphotos.com/techniques/ground_glass/

    Jon
     
  5. Dave Parker

    Dave Parker Inactive

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    There are many different methods to produce ground glass, Dick's method is a good one, I have developed a different method that I think produces a better screen, but for the do it yourself home person, Dicks is a great method to follow.

    Dave
     
  6. User Removed

    User Removed Guest

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    I have used Dicks method, and produced a very smooth ground glass, althought it was quite grainy.

    I would suggest buying a 4x5 from Satin Snow. For how cheep they are....you cannot go wrong. Not to mention, they are also the nicest ground glass I have EVER seen in my life.
     
  7. Donald Qualls

    Donald Qualls Member

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    Very dangerous!! Though the hobby shop material often doesn't carry an adequate warning, if this is in fact acid it's hydrofluoric acid, and getting any of it on your skin can lead to deep, hideously painful acid burns that are very difficult to treat and extremely slow to heal. Even the very weak solution sold for glass etching is dangerous.

    If you want to etch glass with chemicals, it's probably safer to use very strong lye; you "only" need a full face mask, rubber apron, and full length rubber gloves to make a strong solution of lye (which you can buy at the grocery store as a drain opener), which will then slowly etch the glass. The glass needs to be very clean to get an even etch, and you'll want/need to protect the side that isn't to be etched.

    MUCH easier to make ground glass with abrasives and a glass grinding tool, similar to the methods amateur opticians use to make telescope mirrors and lenses; if you use very fine abrasive, you'll get relatively fine ground glass (320 aluminum oxide is probably about right, though finer won't hurt, just take longer).

    However -- for what he charges, if it takes you an hour to make the ground glass, you'd have been better of getting one from SatinSnow, even if it weren't a superior product to whatever you're likely to make yourself (and all reports are, it *is* superior).
     
  8. Dave Parker

    Dave Parker Inactive

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    I agree 100% Donald, even the weak solutions sold in hobby shops can be very dangerous, I know, we experimented with it! anyone that chooses to use acid to make ground glass, must take the proper precautions as it will cause very serious burns as you have stated.....I was not trying to suggest that anyone use acid, without taking the proper precautions for their health and well being, I am sorry if it came across that way, thanks for bringing this very important point up.

    Dave
     
  9. nick mulder

    nick mulder Subscriber

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    I like to try things once or twice before I resort to buying a pre-made one - so I'll try the aluminium oxide and get back to yous - as a quick tester I have just taped some cloudy tape over the glass, sheesh it works ok for now ! (lookin at bright stuff only and accounting for the extra thinkness)

    thanks for the suggestions
     
  10. Murray@uptowngallery

    Murray@uptowngallery Member

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    I can tell you if you start with Aluminum Oxide, you will be sorry, unless you have strong arms.

    I made several up to 16x20 with Silicon Carbide that was quick and easy. (Well, the 16x20 does take many times longer than 4x5), I spent about 4 times as long on the Aluminum Oxide 5 micron only 8x10 than for SiC and I still can't get rid of the 'wavies'.

    Regardless of the superiority of professional products like SatinSnow (which I really should try), I just like to make things...I hardly ever shoot film, unfortunately.

    I haven't tried SiC first , then Alum. Ox. Maybe someday.

    Murray
     
  11. nick mulder

    nick mulder Subscriber

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    well, Upon ringing up a glass merchant who advertised repairs, etching and 'tricky stuff' they advised that they had aluminium oxide at a very cheap cost, On arrival I was told that they didnt have it after all and they were refering to another oxide polishing compound - they *did* however have an etching paste that may work - it looks as toxic as all those things mentioned above "Contains Ammonium and Sodium Biflourides - wear full body amour, keep a concealed dagger in addition to your sword when opening pottle"

    gawd, I'll get back to you with the results -
     
  12. Dave Parker

    Dave Parker Inactive

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    I can send you a 4x5 screen for $9.95 + shipping?

    Dave
     
  13. BradS

    BradS Subscriber

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    Nick, That sounds pretty nasty. Really, the glass shop is the wrong place to get the Alumina. Try an arts and crafts store. You can buy a bottle of the stuff for about $7-8 add to that a piece of precision cut glass and another larger, real thick piece to grind on and you're ready to start. Do try it. It's fun and rewarding. I made two or three. I'll never bother again though.
     
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  15. RichSBV

    RichSBV Member

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    Any place that sells rock tumblers would also carry the compound in various grits. Or try the valve grinding compound. It works wonders on hardended steel valves.

    I'm with both sides on this. I have a couple of Dave's GG (and love them), plan on buying a few more when I get around to it. But, I'd also like to grind my own one of these days. Some things are fun to do at least once...

    I have a quantity of the rock polishing compound, and especially after a bit of use, the fine stuff is really fine! I haven't read the links listed, but I would probably just take two sheets of glass and slide them together for a while with the compound in between. I wish I had the free time, but it's really more one of those Winter projects anyway...

    (and how come I can't use the spell checker on an edit... Gees I can't spell any more)
     
  16. nick mulder

    nick mulder Subscriber

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    well, I've done it - and its ok - and I know now what I need to do to make it perfectly next time (dont fiddle so much with it, just pour it on quickly and in a good amount, which can be scrapped off to use again anyway) - but honestly its fine, just a little streaked (from not getting the paste on fast enough and having a sharpish plastic putty 'knife') but the image is there and is more than adequate for my needs.

    thanks for the offer Dave! however I am somewhat in and out of the business of making things, so I really love getting my hands dirty and acidified to find out about different processes - this project is practice for an 8x10 next time round (; a combo 8x10 monorail/ and curved film plane pinhole

    and now I have a pottle of glass etching compound so I can personalise my bottles with all sorts of profound obsenities and the like (;

    *grin*

    i'll get a few pic's in the tech gallery when its complete
     
  17. Denis P.

    Denis P. Member

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    Homemade GG

    I'm rather late here, but I just wanted to add my experience in making my own GG.

    Although I'd much prefer to have Dave's ("SatinSnow") ground glass, the complications implied in sending it across the ocean are not worth it.

    In short, today I made 2 (two) pieces of 4x5 GG in about 5 minutes - no aggressive chemicals involved!

    It's a variation of Dick Dokas' method listed earlier.

    In short: you need a piece of thicker glass to be used as base, some valve grinding compound, a few drops of water, and about 5 minutes of circular motion ("elbow grease").

    You might experiment with various grades of "grinding paste" (i.e. valve grinding compound) first, using smaller pieces of glass, to see which grade suits you best.

    The thickness of glass usually isn't that important - at least for the cameras I use. I used 1,8 - 2mm glass from a glass shop, where they cut it to my specifications - I'm not very successful in cutting glass :sad:

    Anyway, it takes about $2 for the glass (already cut), $3-$5 for the "grinding paste" (that's what the product is called here), and about 5 minutes of work.

    You might inspect the glass every now and then (rinse it in water to wash off the paste and dirt, and then dry it) to see if the sanding is even.

    The two attached photos show the end result - the photo with two glasses on the keyboard shows my DIY GG on the left, and the "original" on the right. The "original" also looks like a DIY job (it came with the camera I got recently), but the grain is quite coarse - probably done by sandblasting (which is almost unusable for this purpose).

    The grid was done with a pencil :smile:

    Regards,

    Denis
     

    Attached Files:

  18. Poptart

    Poptart Member

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    That's good info. I have made a couple of g/gs out of acrylic--very easy with a couple grades of veryfine-ultra fine sandpaper.
     
  19. Dave Parker

    Dave Parker Inactive

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    Actually,

    International problems have been pretty much taken care of, we shipped over 100 international orders in November with no problems at all.

    We will again be back to shipping in the next couple of days, and with all the work we have put into our international stuff and paper work, I don't really anticipate any problems in 2006 on International or Domestic orders.

    Dave
     
  20. severian

    severian Member

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    Brakleen

    Jay,
    What is Brakleen and where do you get it?
    Jack
     
  21. Denis P.

    Denis P. Member

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    Thanks for the update, Dave! I'm glad that the international shipping problems are sorted out. I'll probably order one from you, just in case :smile:

    Regards,

    Denis
     
  22. Fred72

    Fred72 Member

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    First of all i want to say i have never made or used ground glass, so i have no first hand experience. But i was thinking, maybe it could work if you sprayed the glass with some kind of matte varnish? Either like the ones they use for making frosted glass or some ordinary varnish. Like i said i don't know, just a thought i had.

    /F
     
  23. argus

    argus Member

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    I am one of those do it all yourself guys but I withdrew on the groundglass. Commercially made groundglass is brighter than you will ever be able to make yourself and the cost is not dramatically high.
    Buy one. You will not regret it.

    G
     
  24. DavidV

    DavidV Member

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    If you happen to be shooting in West Dogpatch and have a busted groundglass, frosted Scotch tape over plain glass or Lexan does a tolerably good job.
     
  25. Jim Noel

    Jim Noel Member

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    I have made dozens of sheets of ground glass up to 8x10.

    The easiest method is to make two at a time. Obtain some 600 grit, or finer if you can find it. It is available at hobby shops which cater to rock tumblers. Put about 1/2 teaspoon on one sheet of glass. Add about an equal amount of water.

    Place the second sheet of glass on top of the first, and with smooth rotary motion, and only moderate pressure, start grinding. if wheyou check one area has not been ground equally, use a little more pressure in that are as you continue to grind.

    Not difficult, but be patient.
     
  26. Nathan Smith

    Nathan Smith Member

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    I agree with Jim, it is so quick & easy to make a very good true ground glass that I don't see the point in a lot of other (and what seem to me to be inferior) methods that folks try. A small bottle of 600-grit silicon carbide from a rock-hound (lapidary) or hobby shop will last you forever and make many, many sheets of ground glass.

    My method is basically the same as described. I've found that hobby shops carry thin glass (thinner than window glass) pre-packaged for use in framing. If you ask nicely they'll usually cut it for you for free, or for a small charge - although that's really not hard to do you yourself either. I take 2 pieces of 4x5 glass, cover one side of each with package tape as smoothly as possible not to make bumps or lumps in the surface, put the grit between with a little water to make a paste and rub them together in a semi-random orbital fashion. I put the bottom one on a piece of flat masonite, or any flat surface and swap them out from time to time so that they both get ground evenly.
    Wash them off occassionally to ck your progress. Takes 15-20 mins max. Wash 'em off, take off the tape, and you've got 2 good pieces of GG.

    And yes, I do plan to buy a new one from Dave soon, too cheap (for that quality) to pass up!

    Nathan