Borosilicate Ground Glass - Grinding Your Own?

[Len Middleton]

Recently acquired an 8x20 camera project, and put the ground glass that came with it on, and found it quite dim.

So while I have not yet tried grinding my own ground glass, but am wondering about taking on grinding an 8x20 ground glass. And wondering about doing it in borosilicate.

Thoughts, comments, WTF, please ...

Thanks,

Len

[lenser]

To be honest, when I recently worked on restoring a studio Century camera, I simply went to a local glass shop and for about $20 bucks I bought a cut to order sheet of frosted glass. It is bright, it focuses accurately, it was quite reasonable on price and I couldn't be happier.

[E. von Hoegh]

Recently acquired an 8x20 camera project, and put the ground glass that came with it on, and found it quite dim.

So while I have not yet tried grinding my own ground glass, but am wondering about taking on grinding an 8x20 ground glass. And wondering about doing it in borosilicate.

Thoughts, comments, WTF, please ...

Thanks,

Len

Why borosilicate? The only advantage to it is that it has a low coefficient of expansion, glassware like Pyrex is a borosilicate glass. Can you even get it in thin sheets?

[Nathan Potter]

I have ground borosilicate often in the past. No different than grinding soda lime. 600 or coarser 400 grit silicon carbide in water with a few drops of Photoflow work fine. Use a smaller blank of glass for the motion surface; or I use a stainless steel grinding block.

As mentioned in earlier threads it's probably safer to grind a larger sheet first then cut to size rather than try to grind to the edge of the sheet where there is increased risk of edge cracks. OTOH if you've spent a lot of time grinding, and you are somewhat of a klutz, you don't want to break the screen cutting it after grind.

Nate Potter, Austin TX.

[David Karp]

If you decide not to do it yourself, Steve Hopf makes GGs out of borosilicate.

[D. Bryant]

If you decide not to do it yourself, Steve Hopf makes GGs out of borosilicate.

I agree, I think that is your better option.

[dsim]

There are instructions for DIY glass on Steve Hopf's website here.

[Len Middleton]

If you decide not to do it yourself, Steve Hopf makes GGs out of borosilicate.

David and Don,

Steve Hopf was / is a consideration. There is comments on his site regarding the benefit of the borosilicate glass.

However, it was after reading the various threads (Joe Forks, Ian Grant, etc.) on how to do it yourself and the link to the Hopf web site on DIY, that I have considered the DIY approach. In looking at the pricing by Steve Hopf, for ULF it is priced at $1 per square inch for soda lime, and twice that for borosilicate. So for an 8x20, it is 160 square inches, and for standard soda lime glass that is obviously $160, while borosilicate is twice that.

My wife and daughter are both into knitting. The amount of time involved in knitting the same sweater is going to be close to the same regardless of whether one is using cheap acrylic yarn, or an expensive alpaca / wool blend. If one is going to invest significant time, then using the better material will result in a sigificantly better final result, for the incremental different in material costs. Is that a resonable analogy here?

The cost of the borosilicate glass will be more expensive than the soda lime glass, but does it require more effort? Or is it likely to increase the probability of getting it wrong (e.g. scratches, etc.)? Will the final result likely be worth the additional effort and cost involved (i.e. incremental cost issue)?

Thank you for your insights thus far,

Len

PS dsim, I was likely composing when your comment was posted, so I did not read it before this post here.

[cdholden]

Why borosilicate?

It is more durable than regular plate glass, making it harder to break. When it does break, it breaks in larger pieces. This makes for a mess that's easier to clean up than smaller splinters and shards.

If breaking glass is a concern, consider acrylic plus a fresnel.

[E. von Hoegh]

Thanks; I was just perusing Hopf's website.
I never thoght of using it, I have to make a new GG for a 4x5 back one of these days, maybe I'll give it a try.