Emergency Ground Glass

Gatsby1923 · Aug 26, 2006

OK my ground glass was accidentally destroyed tonight and I need to shoot some 8x10 tomorrow. I will probably order a new one from Satin Snow glass. Until then I think I will just make one myself from some old 8x10 picture frame glass. I have two options easily available. First, being a can of the spray on glass frosting paint you can get at Home Depot. Seems easy enough to do and I have seen it used on small arts and crafts projects with successes. Option #2 is get some acid for etching glass. I can get this at my local craft store. I have a feeling that is a lot harder to do than spray painting glass So if any one hear had to made a ground glass in a pinch what would you do?

Dave M.

Dave Parker · Aug 27, 2006

Dave,

Here is what I would do!, Get a roll of scotch 3/4 inch tape, the opaque type and get yourself a piece of glass that will fit your camera, lay the tape edge to edge and you will have a usable piece of glass to shoot with...the craft store acid is very difficult to get even and the spray is very difficult to apply without dirt in the spray, the tape has saved my ass more than once..

Dave Parker
Satin Snow Ground Glass

Robert Hall · Aug 27, 2006

Ah, so now we know how Dave makes his glass!

JBrunner · Aug 27, 2006

Yeah, but somehow he gets those seams so dang close together....

BBarlow690 · Aug 27, 2006

You can also use a cheap plexiglas picture frame. Cut it to the right size, and go at it with 400 grit sandpaper. Richard Ritter shows how in his DVD, and it works.

He starts by showing how he uses an oversize piece of plexi with Velcro buttons as a GG protector. It can, in an emergency, be scored and broken off to fit as a GG, and then abraded with the sandpaper that you carry with you. Voila! Camera Repair in the Field. The protector part is a little late for you right now, but perhaps a suggestion for the future (unless you broke it by dropping it, like me!).

Good luck!

Bruce Barlow

Roger Hicks · Aug 27, 2006

Yet another option (which I have used) is two sheets of glass and some valve grinding paste -- though I imagine very few people have valve grinding paste (for car cylinder heads) handy nowadays. Even so, it must be easier to get and safer to use than hydrofluoric acid.

Something i may try later today (because I'm curious and I've just thought of it) is a sheet of drughtsman's tracing acetate (like the old Kodatrace) secured to the glass with spray adhesive or simply taped at the edges or even stretched tight and held by the GG frame.

Cheers,

Roger (www.rogerandfrances.com)

noseoil · Aug 27, 2006

The picture frame glass idea works well. To do the surface, tape one side with a heavy tape to avoid scratches. Use some lapidary carborundum (400 or 600) to work the other side with a smaller peice of glass and water, small circular motions. It works, but takes a bit of elbow grease. tim

cdholden · Aug 27, 2006

I've got a spare SS gg I'd be willing to get rid of. Send me a pm if interested.
Chris

Steve Smith · Aug 27, 2006

I have mentioned this in other threads before but the 'ground glass' in my camera is a piece of fine textured polycarbonate (General Electric fine textured Lexan) fixed to perspex (plexiglass) with optically clear adhesive.
This material is usually used by screen printing companies to produce labels, nameplates and membrane switch graphic layers. If you have a sign making screen printing company or a membrane switch manufacturer in your area they should be able to supply you with a piece. A bit to fit a camera would generally be considered an off cut and would probably end up in the bin.
This material is very similar to the draughting film suggested by Roger but is usually a bit thicker.

Steve.

Jim Noel · Aug 27, 2006

I use 600 grit carborundum and two pieces of glass of the size needed.

I end up with two new ground glass using the same effort as for one. Also by using two pieces the same siz I believe I monimize the chance of having part of the glass ground more or less than the rest.
Jim

Elox · Aug 27, 2006

Far VERY temporary fix, I have used Glad Press'n Seal plastic wrap. Work surprisingly well and it will stick film rails in a 35mm, Polaroid film packs, backs, etc.

Gatsby1923 · Aug 28, 2006

Well the rain has given me a reprieve until at least tomorrow. I saw a lot of ideas I never would have thought of. I am going to try a few of them and report back.

Dave M.

jimgalli · Aug 28, 2006

Oh great Roger. I used up all the valve grinding compound on glass and now the flathead has started missing. Sounds like an exhaust valve.

Mike A · Aug 28, 2006

The easiest for me when I fell on my ass with my rig in tow was what Tim and Jim suggested. I bought the glass at the local project center for a few dollars and contacted a local guy that does industrial lapping, He couldn't see charging me for the carborundum so he gave me a bag of 400 and 600, I returned with a print for his office.

There's a thread some where around here on how to grind the glass, it's very simple.

Mike

Dave Parker · Aug 28, 2006

Grinding glass is actually pretty simple, the different qualities of glass will depend on the medium you use, I found carborundum to be pretty course, hence the reason I worked with different compounds to come up with a high quality grinding compound comprised of several different materials, but again, making ground glass is pretty simple, heck anyone with access to a sand blaster can make a ground glass in about 30 seconds..albeit a low quality one with poor light transmission properties.

Dave Parker
Satin Snow Ground Glass

nworth · Aug 29, 2006

The following from my trusty 1943 edition of the Photo-Lab Index:

Ground Glass Substitute
Water 200 cc
Rice Startch 20 grams
Water glass (sodium silicate solution, sp.gr. q. 1.3) 100 cc.

Mix the above by first rubbing the starch up with water, then add the water glass solution. Level a sheet of glass and pour enough of the above solution on to cover it and permit it to dry.

The coating is fragile and affected by water; it should be protected by lacquering with any good cellulose lacquer.

Etching Solution
For Frosting Glass

Sodium or potassium fluoride 4 grams
Gelatin 4 grams
Warm water to make 1 liter

Warm the solution (not over 125F or 52C) and stir until gelatin is dissolved. Coat the resulting solution on glass and permit to dry thoroughly.

Immerse the dry coated glass in 6% hydrochloric acid solution (made by diluting 6 parts of concentrated (36%) hydrochloric acid with 30 parts of water) for 30 to 60 seconds, and permit to dry without washing. After the glass is dry, the gelatin may be removed with hot water, leaving a fine etched surface.

(Note that in the last formula, fluorides are poisenous and dangerous; concentrated hydrochloric acid is dangerous. If you try this, wear gloves and do it in a well ventilated area.)

Dave Parker · Aug 29, 2006

nworth said:
The following from my trusty 1943 edition of the Photo-Lab Index:

Ground Glass Substitute
Water 200 cc
Rice Startch 20 grams
Water glass (sodium silicate solution, sp.gr. q. 1.3) 100 cc.

Mix the above by first rubbing the starch up with water, then add the water glass solution. Level a sheet of glass and pour enough of the above solution on to cover it and permit it to dry.

The coating is fragile and affected by water; it should be protected by lacquering with any good cellulose lacquer.

Etching Solution
For Frosting Glass

Sodium or potassium fluoride 4 grams
Gelatin 4 grams
Warm water to make 1 liter

Warm the solution (not over 125F or 52C) and stir until gelatin is dissolved. Coat the resulting solution on glass and permit to dry thoroughly.

Immerse the dry coated glass in 6% hydrochloric acid solution (made by diluting 6 parts of concentrated (36%) hydrochloric acid with 30 parts of water) for 30 to 60 seconds, and permit to dry without washing. After the glass is dry, the gelatin may be removed with hot water, leaving a fine etched surface.

(Note that in the last formula, fluorides are poisenous and dangerous; concentrated hydrochloric acid is dangerous. If you try this, wear gloves and do it in a well ventilated area.)

Yup,

And following these instructions, you will end up with a 1943 quality ground glass, which over the years we have found is lacking when it comes to resolving power...this guy was after a quick fix for a situation that had occured..The course nature of these two methods may not derive the solutions and fine grain that most photographers demand these days, as time has moved on, so has solutions.

Dave Parker
Satin Snow Ground Glass

raucousimages · Aug 29, 2006

Lesson #1 Protect your ground glass.
Lesson #2 Keep a spare in each size you shoot.
knowing how to make do in an emergency is a great bit of knowledge.

Mike A · Aug 29, 2006

Mike A said:
The easiest for me when I fell on my ass with my rig in tow was what Tim and Jim suggested. I bought the glass at the local project center for a few dollars and contacted a local guy that does industrial lapping, He couldn't see charging me for the carborundum so he gave me a bag of 400 and 600, I returned with a print for his office.

There's a thread some where around here on how to grind the glass, it's very simple.

Mike

I forgot to mention that I the other easy thing I did was ordered one of Daves beautifully ground peices for my primary viewing screen.

Mike

Loose Gravel · Aug 30, 2006

I always wondered about coating a piece of glass with parafin. Just a thin coat. Is not a Boss screen made with wax between layers of glass? May not work in the desert on a hot day.

Dr. Magico · Sep 21, 2006

I come in this focusing screen question about a year or two later, so i wont save the day but there is a very easy emergency solution to a broken screen it si called: "sour milk".
Pour it on the glass let the exes of fluid drip out, let it air dry
et voilà.

Terence · Sep 21, 2006

Dr. Magico said:
I come in this focusing screen question about a year or two later, so i wont save the day but there is a very easy emergency solution to a broken screen it si called: "sour milk".
Pour it on the glass let the exes of fluid drip out, let it air dry
et voilà.

How do you keep the cats from licking it clean?

Dr. Magico · Sep 22, 2006

Terence said:
How do you keep the cats from licking it clean?

Well, cats they do what they want, (but just make sure its not a Norwegian-cat, they're huge, and then you might need a lot of milk).
( buy the way wouldn't it give you a cute little side-shot? a cat looking the camera).

Emergency Ground Glass

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