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lapping/polishing amethyst: some help please?


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#1 Izzy

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Posted 14 October 2010 - 05:16 PM

Hey guys,
Before this project I had 0 experience lapping/polishing stones. I bought some amethyst off ebay (I know, probably not good quality, but it was cheap). I have an EZ-Lap diamond sharpening stone. One side is medium grit (400), and the other side is "superfine" (1200 grit).

I bought a diamond cut-off wheel hoping to cut my stones (I have 10 that fit in the palm of the hand, give or take a little). Having never used one, I ended up mangling it horribly (lessons learned :blush: ). Anyway, to finish cutting off my first little piece, I used a stone carving chisel and broke through what I didn't get a chance to cut through.

I have the stone faceted (by hand, so it's kind of a "dt point" shape, but freehand) to 400 grit. Soon, I will be going over it with the superfine side. My question: Will 1200 grit be smooth enough to polish, or is there something more I can do? I don't own a tumbler and won't have enough spare change to buy one for (quite) a while, and don't have enough stones to put in one to make it worth it. I do have a foredom, with all kinds of buff wheels, but wouldn't know what kind of compound to use.

I plan to make a setting for this stone to hang as a pendant. But need to have the stone finished before I go there. I hope to post some pics soon. I'm getting married tomorrow, and won't be around a computer for the next week or so (or working on the stone for that matter).

Any help would be appreciated. Thanks in advance,

Izzy
know something about everything, and everything about something.

#2 lopacki

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Posted 14 October 2010 - 05:43 PM

Izzy,
I usually go directly from 1200 mesh to polish at 14000 mesh. You need to make sure the entire surface is truly 1200 or you will find that when you polish the left over scratches stand out like a sore thumb. If you have the Foredom I'd say buy some 14000 diamond paste.

Hope the wedding is a great time ............ All my best ....... Danny

#3 Janel

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Posted 14 October 2010 - 06:28 PM

"Hope the wedding is a great time"

And your life there after, too! Have a happy life!

Janel
Teachers open doors, you enter by yourself. Chinese proverb
What you can do, or dream you can, begin it; Boldness has genius, power and magic in it. ~ Goethe ~


Janel Jacobson's web site

#4 kenneth neaves

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Posted 14 October 2010 - 10:57 PM

izzy,if you have the stone faceted and you put it in a tumbler for any amount of time it will round off your facet junctions.you need to polish it one facet at a time with a flat lap with 12000 or higher diamond paste,and like daniel said,if you don't have all the scratches out they will stick out like a sore thumb.best regards,kenneth

#5 Izzy

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Posted 19 October 2010 - 03:41 PM

Thanks for all the advice. The wedding was great, but we were completely exhausted by time we got to san diego. We went to old town yesterday and had a blast. I picked up an orthocera fossil at a gem/mineral shop. I got a rough garnet as well.

can't wait to finish this amethyst project.

Question: What do I put the diamond paste on to polish the facets? I have seen people use dowel rod shaped with a file and mounted on a screw top mandrel. Is there some other way that would produce better results?

thanks again,

Izzy
know something about everything, and everything about something.

#6 lopacki

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Posted 19 October 2010 - 09:29 PM

Izzy,
If you are cutting true facets (flats) by hand and not using a machine, get yourself a flat piece of metal or hard plastic apply the paste to it and then rub your flat back and forth, this will give you the finish your after. The main problem with trying to do a perfect flat in this way its almost impossible to keep the flat face flat on the surface your using for polishing.

Remember if your going to use more that one mesh, you will need separate flats for each mesh size.

You might check on the web and look at Jam Peg faceting.

All my best .......... Danny

#7 yloh

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Posted 12 April 2011 - 05:08 PM

score the metal or hard plastic, will be better.
and lock your arm when ploshing could help.
Yloh



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