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Craig Tuffin
31-Aug-2010, 17:47
Well I can't find anyone that supplies the grinding compound in this part or any part of Australia so I decided to try and get acid etched glass from the glass warehouse up the road. Unfortunately the thinest frosted glass is 4mm....is this too thick for a groundglass...will it be darker???

The other option I have is to have the 2mm clear glass finely sandblasted on one side.

Any advice is appreciated.

Craig

eddie
31-Aug-2010, 17:58
grind your own.......

Chauncey Walden
31-Aug-2010, 18:18
Did you look for lapidary dealers (rock shop tumbling grit)? How about valve grinding compound from an auto parts store? Or, even silicon carbide paper placed on a sheet of heavy glass.

Craig Tuffin
31-Aug-2010, 19:00
Great suggestion....valve grinding compound I CAN get. What diameter glass will produce the brightest image...2mm, 3mm?

Cheers

Ty G
31-Aug-2010, 22:12
Craig, you are not going to notice a difference in image from various thicknesses of glass. I have seen many thicknesses and they all work fine. What DOES matter is if the ground glass mounts in from the inside of the frame or the outside (towards you). If it mounts in from the inside, then changing thickness WILL mess up registration. If it mounts in from the rear, then it will not matter. Just make sure to put the ground side toward the lens.

Craig Tuffin
1-Sep-2010, 01:58
Cheers Ty

archer
1-Sep-2010, 02:25
Dear Craig;
most window glass is slightly thinner than 2mm and grinding compound grit is available at any lapidary supply. Start with 400 grit and finish with 600 grit and you will have the best ground glass for 4x5 and smaller, for 5x7 and up 400 grit will be sufficiently fine and slightly brighter if just a little grainier. I have only bought 1 ground glass in decades and that was this year because I got lazy but at $30 bucks plus shipping and the fact that my GG's are as good or better, it doesn't make sense to me especially since for the same amount of money I can buy the glass and grinding compound to make 20 or more if I cut the glass myself or a dozen if I buy the glass pre cut.
Denise Libby

Lynn Jones
1-Sep-2010, 16:08
And besides all this, the thickness isn't that important, it's the ground or etched surface that is important.

Lynn

eddie
1-Sep-2010, 16:22
i get my ground glass from my local glass guy. WAY cheaper than $30 i can assure you.....closer to free and no labor involved.

Ivan J. Eberle
1-Sep-2010, 16:33
Big improvement in brightness with a lapidary ground especially for use as a camera GG versus simply a piece of glass that's merely etched or sandblasted. I found it rewarding and entirely worth the effort to learn how.