DIY Ground Glass: Is Etching an option?

[LabRat]

A really good, bright GG from back in the day was a combination of being blasted for the matt surface, then being fumed with hydrofluric acid (thanks DJ!!!) to create a little transparency, so there was some aerial image going through it... But enough matt surface to focus on... Those fumed glasses were mostly made with banned substances, with the last being made in Belgium (thanks, Drew!!!) some years ago... And were a specialized process, difficult to make proportions right for a good balance, and may have a different effect with long or short FL's... (Almost like a semi-fresnel effect...) You will often find them on Graflex SLRs or other reflex cameras as the viewing screen...

If you need a good, quick emergency GG, I had to use some window frosting spray to paint over some windows, and it had a nice ground surface (but not as tough as the glass) but if it is inside the camera, and you go easy on it, it should last for a while... (Mist over it a few times making very light passes, with dry time in between...)

Some frosted/textured surface acrylics have a surface that reminds me of the old style etched/blasted glass GG's, so I might try them out sometime...

Steve K

[Struan Gray]

I've done a lot of hand-processing of silicon wafers using HF. It is not something you can do safely at home, notwithstanding the glassmaker and gee-whizz videos on YouTube. HF is not just another strong acid - there are non-obvious dangers in its use - and it can do serious, lasting, and painful damage to your body. It's not worth the risks of using it without proper lab grade safety equipment.

The etching gels do frost glass, but the only one I ever tried was too uneven to consider using for a camera ground glass.

I'd say do things the old way with grinding grit and a little patience. Or find a signwriter/glass shop/hobby workshop with a sandblaster.

If you need something quickly, a layer of Scotch tape on plain glass works pretty well.

[Drew Bedo]

Thanks everyone. So—no etching.

[Jim Fitzgerald]

For my 14 x 17's I use frosted window film that I got from Lowe's. Used on my acrylic GG it works great.

[Jim Jones]

Glass from cheap picture frames is usually thinner than window glass, and thus better in some applications.

[Ron (Netherlands)]

(...) sandblasting. It seems like this would be one possible way to get a ground glass done?

No not a good idea. Before I got into grinding my own screens, I had brought two glasses to a glass supplier who had sandblasted them. On first site they look nice, but you can hardly focus on the screens since the sandblasting result is way too coarse.

[dieter]

Use silicon carbide. It does not take long and it is easy. I am making ground glass this way in this video:

[Nodda Duma]

Having worked in an optical shop, I have some familiarity with grinding & polishing optics. Barring a grinding station, hand grinding is best way to achieve a consistent and even finish.

Silicon carbide is awfully coarse. Why not use aluminum oxide in a finer grit?

[Ron (Netherlands)]

Use silicon carbide. It does not take long and it is easy. I am making ground glass this way in this video:

Great video - and what a fast work! Somehow I guess I missed that part where you were making the bellows :-)

[Ron (Netherlands)]

1. Silicon carbide is awfully coarse.
2. Why not use aluminum oxide in a finer grit?

1. Depends what grade you would be using - lower than F400 would be too coarse indeed
2. very much interested in what grade that would be

I grinded a screen for my Rolleicord with silicon carbide and it has the same satin finish as the original, perhaps even a bit finer.....