How do you grind down a 4x5 ground glass?

[Alain Briot]

Hello,

I need to find out information on ground glass grinding.

I need to replace the ground glass on my 4x5 Linhof. I found a spare one but it is too wide by about 1/8th of an inch and won't fit into the Linhof back.

How do you size it down? It seems the best is to grind it down. How do you do that? With a band sander? If anyone knows please let me know. I don't want to break this ground glass!

Thanks.

Alain

[Eric Woodbury]

I bet a glass shop will grind it down for you. They use emery cloth on a power belt sander.

[Moe_4073]

If you know someone who works with stained glass, they should have the correct tool (a wet-bit diamond router) to do the job properly. You run the risk of chipping the edges of the glass if you use anything else. Regards,

[ronald moravec]

Put some wet dry emery on a glass plate, add water, and rub the offending edge back an forth holding the glass vertical. Change direction of the way you hold the glass so as not to make a tapezoid shape. In other words, put the opposite edge into the space between thumb and finger.

Make a pattern from cardstock that does fit so you can measure progress.

400 grit emery for small amount of removal and 100 for large amounts.

Cover the ground and ruled side with food wrap and then tape around the whole glass so not to damage the surface. Wash with soap and water and rinse with distilled water two times air drying in a vertical position and cleaning accumulated water from the lower edge often.

If you go the shop route, make two patterns, give them one and keep one, but let them know there are two. Protect in a similar fashon. Mark the edges of the pattern with v ink marks with the point of the v on the edge so they can`t cut it down.

[Colin Carron]

I've done a bit of stained glass work in the past and the technique is to scribe the line with the diamond cutter then snap off the excess in small bites with a special pair of pliers. Works surprisingly well though leaves a rough edge to be smoothed off. Using new glass makes a big difference though. If it is old it becomes more brittle and working it is less predictable. I would have thought a good glazier would do it for a nominal charge.

[Dave Brown]

For what it's worth, I recently (sucsessfully) used a tile saw with a diamond blade to cut down glass for the negative carrier on my 10 x 10 enlarger.

[Herbert A Terbrack]

I had the same problem recently when replacing the ground glass on my Cambo SC. I have a drill press and used a drum sander to grind away 1.5 mm of the edge of the glass to fit. I marked the glass with a Sharpie marker and patiently sanded the edge until the excess glass was removed. You have to be patient. Make repeated passes over the sandpaper, and if you're patient the edge will be smooth. I think this took me about 30 minutes. Aluminum oxide paper seemed to work best, however any sandpaper could work. Grit of 150 or better. I used around 200-220.