Aug 15 2008
Jasper after Sanding Cycle in Rock Tumbler
The sanding cycle finally finished yesterday for the jasper that I have had in the rock tumbler. Now comes the fun part! I took the photograph here after I got all of the silicon carbide washed off of the stones. They’re still wet in the photo so it gives something of an idea of how they’re going to turn out when complete.
It will still be about two more weeks before it’s finally polished, assuming that everything goes well. They’re just starting the pre-polishing cycle now and that should take about a week, give or take a day. Then the polishing cycle will take about another week.
Depending how the stones look after that, they may need a few extra days in a burnishing cycle. It’s really hard to give an estimate on that, though, until I actually see the results after the polishing cycle. If I had to guess, I would say that some burnishing will be needed but probably only about three days worth.
As the stones go through the grinding and sanding stages, they lose some of their volume so it’s important to add some type of filler in the final stages. Up until now, I have been using small plastic pellets. I hate these stupid pellets with a passion. They’re supposed to be reusable, but they’re so annoying that I end up just throwing them away. Then I get even more annoyed that I’m wasting something that’s supposed to be reusable. I finally broke down and bought some ceramic media to use as filler. I’m trying it for the first time in this pre-polishing cycle. I can already tell that I’m going to like it better since it’s bigger and heavier.
9 Responses to “Jasper after Sanding Cycle in Rock Tumbler”
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Beautiful! Thanks always for sharing. Maybe I should also look out for nice looking stones when I take a walk.
Thanks to both of you, Melissa and Betchai.
I hope you start picking up some stones, Betchai, especially with all the interesting places you go. I bet some lovely ones wash up on those beaches of San Diego.
Maybe I could be called an amateur lapidary-wannabe, Melissa.
I do love collecting and polishing the stones, and I am working on learning to cut them now. I’ve thought that one day I might feel ready enough to offer some of my stones for sale, but for now I just enjoy them and on my own and give them as gifts to friends.
It can take a good length of time to polish them carefully, Cambios. I use a rotary rock tumbler which is basically a device that just rolls a barrel slowly in a continuous loop - something like a hamster wheel. You add the stones, some grit, and water to the barrel and then place it on the rotating rods. The process is a natural one where the stones are smoothed and polished by tumbling against one another and the grit. Throughout the process, you use different forms of grit to keep enhancing the process. You start out with a coarser version that helps grind away the worst rough patches. You then move through a series of successive finer grits as the rough patches and scratches become less and less pronounced. In the final polishing stages, you are using an extremely fine abrasive that is basically just buffing the stones so they’ll shine and have that “polished” look. The overall process, depending on the stones, can take anywhere from 3-8 weeks. You don’t want to move too fast or you’ll be sanding away more than just the rough patches.
wow, and i actually have picked up some cute rocks from Torrey Pines, and I just simply washed them with soap and water, they don’t look polished at all, I put them in my pots as decorative stones. The process you mentioned above really takes more effort but I bet the stones will look much lovelier. I think I should collect more interesting looking stones, inspired by how you make the stones attractive here.
I have three rock tumblers - actually, four since one can be set up as a double barrel. You definitely can’t toss just any new stone in because you could be at any stage of the tumbling process and each of these stages uses a different size grit of abrasive. Plus, some stones cannot be tumbled together effectively. If you try to mix stones with a Mohs hardness of 5 with those of 7, the softer ones will get eaten alive if you’re not careful. It’s best to keep a single batch in the same hardness range.
There are some exceptions to this and there are times when you can toss extra stones in, but that’s probably way more information than you care to hear!
Where in San Diego can you buy grit for stone tumblers? (I know it’s available online, but the shipping charges are very high.) Or can you recommend online stores with reasonable prices and shipping? Thanks.