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CR Roberts
23-Nov-2006, 02:54
The subject of homemade ground glasses is certainly not new. Much has been written on the topic and some very valuable and informative presentations have been made. Unfortunately, circumstances did not allow me to follow any of this great advice when I broke my ground glass last evening. I plan to use the camera today and needed a quick but decent replacement with no time to order grinding grits.

So, with one dollar I obtained a 4 x 5 piece of window glass from my neighborhood hardware store and another couple of bucks bought me a 3-sheet packet of Norton "3X" 180 grit aluminum oxide sandpaper. I washed the glass thoroughly, covered the intended clear side with masking tape, donned a pair of latex (actually, latex-free) gloves, pulled a dust mask over my proboscis. laid the sandpaper on my clean workbench and began scrubbing the glass over it in a random pattern. After every hundred strokes or so, I brushed the sandpaper clean and continued sanding. After about an hour and a half the ground glass side was uniformly milky, so I carefully washed it with soap and water, removed the masking tape, washed the glass again, patted it dry with paper towels and installed it in my camera.

It's beautiful and at least the equal in brilliance and smoothness to the commercial glass it replaced. I'm sure even better results could be obtained by using 220 grit aluminum oxde sandpaper, but -- of course -- I'd probably still be sanding.

At any rate, I was able to create a very nice ground glass in less than two hours without having to obtain exotic grinding grits from an astronomical telescope making supply house. Sure -- I'll make a glass the "right way" someday, but for now, I'm a happy guy.

If you follow this easy method of fabrication, please make sure you use aluminum oxide sandpaper and keep it, your glass, your workbench and your hands scrupulously clean as you work. Try it -- it works and it's (sorta) fun!

Capocheny
23-Nov-2006, 04:07
CR,

I usually have a couple of extra ground glass kicking around the camera closet so I never have to worry about not having one readily accessible.

But, it's always good to know how to make one... just in case!

Thanks for sharing! :)

Cheers

C. D. Keth
24-Nov-2006, 15:09
CR,

I usually have a couple of extra ground glass kicking around the camera closet so I never have to worry about not having one readily accessible.

But, it's always good to know how to make one... just in case!

Thanks for sharing! :)

Cheers


I made a new one (actually two...don't ask) for my 5x7. I started with 320 grit SiC and went down to 5 micron aluminum oxide. It' is MUCH finer grained than my old glass and I devised a test and measured it consistantly a stop and a third brighter than the old glass, too! It cost me $15 total for glass and grits and a full evening of my time.

GPS
24-Nov-2006, 15:24
1 1/2hr of sanding? You have my medal for patience! How about your arms? Were they able to lift the camera after that? Once I needed home made gg - when I started to sand it, I realized I'm not after the medal so I cut the sand paper for my circular rubber cone, put it on a drill and let the machine do the work for me. You have to change the sanding direction more often but it works. I finished it with a few hand strokes, the gg serves still today.

geowulf
12-Nov-2008, 08:52
I use my father-in-laws 'lap' table. it's a vibrating device that 'sands' the glass for me.

Mark Sawyer
12-Nov-2008, 09:20
In a pinch, the spray-on glass frosting from the local hardware store makes a nice "ground" glass in a few minutes.

Glenn Thoreson
12-Nov-2008, 11:56
I use fine grit valve grinding compound. The NoVue window frosting spray works well, too. For glass, I save the junk glass plates that show up around here. They're the perfect thickness. About the same as the commercial stuff that comes in the camera.

SaveBears
12-Nov-2008, 13:27
Wow, 2 hours! Yikes, the 4x5 screens I have ground normally take me about 10 minutes!

Chauncey Walden
12-Nov-2008, 16:01
As an experiment, I purchased a piece of 11x14 non-glare glass from Hobby Lobby for $9. It works for focusing, is very bright, but is too transparent for an overall view. It could be used for composing by moving you head around the screen. On the other hand, you don't need clipped corners to see the aperture! So, if you are on the road and break your only GG, emergency help is as close as your nearest Hobby Lobby or Michael's.

Peter De Smidt
12-Nov-2008, 16:43
Or in an emergency tape glass with a satin "scotch tape" style tape.

shadow images
14-Nov-2008, 09:07
As an experiment, I purchased a piece of 11x14 non-glare glass from Hobby Lobby for $9. It works for focusing, is very bright, but is too transparent for an overall view. It could be used for composing by moving you head around the screen. On the other hand, you don't need clipped corners to see the aperture! So, if you are on the road and break your only GG, emergency help is as close as your nearest Hobby Lobby or Michael's.

Do you know if you used regular or conservation nonglare? The reason I ask is I own a frame shop and have thought about using a piece of conservation nonglare for an 8x10 camera that is on its way. Was your glass frosted on both sides or just one? Thanks Lyle

Jim Noel
15-Nov-2008, 12:48
I use framing glass, not window glass and make two at a time. Sprinkle about 1/2 teaspoon of 600 grit aluminum oxide powder in the middle of one sheet, add half as much water. Lay the other sheet on top and begin moving it in a random pattern. check every few minutes to learn when the glasses look good, and insure the corners are ground evenly. May occasionally have to add tot he water and oxide. Ten minutes is usually more than enough grinding, and then rinse of with distilled water containing wetting agent, stand on end to dry and they are both ready to use.

NonFiction
15-Nov-2008, 19:17
I had the glass shop sandblast a cut-to-size piece of framing glass, and it worked pretty darn good. A tiny bit grainier maybe, but no discernible brightness difference as compared to the Satin Snow one I had made.

Tim Meisburger
16-Nov-2008, 06:13
Seems to me those little sandblaster things they use to etch kitchy sailing ships and Elvis portraits on glass mirrors ought to work, but what do I know...

jnantz
16-Nov-2008, 07:58
i use a piece of waxed paper, and it works great.
cheep too.

Colin Graham
16-Nov-2008, 08:48
Do you know if you used regular or conservation nonglare? The reason I ask is I own a frame shop and have thought about using a piece of conservation nonglare for an 8x10 camera that is on its way. Was your glass frosted on both sides or just one? Thanks Lyle

I grind the plain side of non glare glass for mine. I first thought the etched side might ghost or confuse the focusing of the image on the ground side, but it really doesn't seem to at all. Although using glass that is etched equally on both sides might be a different story. Anyway, the reflections on regular groundglass used to drive me nuts so I'm glad I tried it, really seems to make the screen brighter and easier to focus on.

Chauncey Walden
16-Nov-2008, 09:36
Lyle, just one side.