Making a ground glass

[RSalles]

Gens,

What's the amount of grinding powder required for a 4x5 GG - average?
Any known good source in USA apart the bay one?
What could I use to trace fine black lines on the glass which will not go away with the first alcohol wet clean cloth?
I have tried myself grinding with sandpaper and water but took too long and I gave up,


Thanks,

Renato

[Alan9940]

Gens,

What's the amount of grinding powder required for a 4x5 GG - average?
Any known good source in USA apart the bay one?
What could I use to trace fine black lines on the glass which will not go away with the first alcohol wet clean cloth?
I have tried myself grinding with sandpaper and water but took too long and I gave up,


Thanks,

Renato

Hello Renato,

I think you may have posted in the wrong thread, but I'll try to help. I never measured the total amount of grinding powder used, but it's not much. I bought two different grits--one somewhat coarse and the other fine--off eBay dealers for about $20US. If all you ever intend to grind is 4x5 or smaller, then you'll have enough for more GG's than you'll probably ever do. It's easy and fun to make your own!

Good luck!

[Jim Jones]

. . . What could I use to trace fine black lines on the glass which will not go away with the first alcohol wet clean cloth?
I have tried myself grinding with sandpaper and water but took too long and I gave up,


Thanks,

Renato

Rather than draw or paint a grid on the ground glass, I scribe them with something like a needle held in a pin vise. This leaves light, not dark, lines on the GG. They are clearly visible, but less obtrusive than any drawn or painted lines I've seen on commercial GGs. Some people use a graphite pencil. A grid could be drawn and printed on clear film with a computer.

[Oren Grad]

Moved to its own thread in DIY.

[Dan O'Farrell]

Renato, try this link, which shows several grades of lapping grit at Lee Valley, in Canada.


http://www.leevalley.com/en/Wood/pag...17&cat=1,43072

Dan

[RSalles]

Oh shame on me, I thought I was asking in the thread already opened about the subject but have opened a new one!


Thanks Alan, Oren, Dan and Jim,

Cheers and sorry,

Renato

[barnacle]

I wonder how well carborundum paste, as sold for lapping engine valves, might work?



Neil

[Peter De Smidt]

The valve grinding paste I tried a number of years ago was too coarse for making a good ground glass. I don't have any idea, though, how similar various brands are.

[Ian Gordon Bilson]

You will notice the tin shown contains two grades of grit. I have used both in succession to reasonable effect.

[John Kasaian]

I've seen some excellent ggs done in a blasting cabinet.