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Techniques for CollectorsTumbler advice?

1st Sep 2016 22:26 UTCDennis McCoy

I just picked up a small tumbler at an estate auction. Any advise on what I need to tumble Brazilian amethyst?

2nd Sep 2016 12:57 UTCMatt Courville

Hi Dennis, I would think that you simply follow the same principle as with any quartz. Our club uses a number of different grit sizes, similar to what would be done to polish a cab for a necklace,etc.. I personally would buy at least 4 grit sizes and experiment a bit -it does take a lot of time though. Remember to mix-in only similar hardness rock with the amethyst, or the grit will over/under tumble;) One member uses accumulated cut-offs and scraps we keep from other lapidary work and tumbles them for her grandkids as a Christmas gift -potential ideas? Have fun!

Matt

2nd Sep 2016 16:54 UTCTravis Hetsler

http://www.bellevuerockclub.org/tumble.html

2nd Sep 2016 20:57 UTCSteve Federico

Hi there,this kind of quartz can be prone to spalling and chipping.I recommend using plastic pellets with it in all stages.My personal grit stages are:80,180,220,400,600,800,1,000,polish.I never burnish after final polish.Wash them and buff on old blue jeans type material works good.I do this because if one breaks in burnishing stage all that time and money is lost.Why take the chance?Please post some pictures when done I would love to see them.........Steve

6th Sep 2016 02:11 UTCDennis McCoy

Thanks for the tips and the website info. I'll let you know how it turns out.

10th Nov 2016 23:00 UTCTim Jokela Jr

Try to mix small material in with larger to cushion.

Watch load size and rotation speed, if it's too fast and harsh ame can bruise.

I run 12 pounders full of ame with 80, 220, 500, and polish, but do the last 3 in a vibe, so YMMV.

A month in coarse alone isn't too unusual, well rounded rocks without deep crevices and fractures are the way to start.

Happy tumbling!