Fractures?

it depends on the rock but also on the level of rock in the barrel to little and they smash each other up if you dont have enough for 2/3 full add some pellets to get there -- most people dont use pellets till after the rough grind 60/90 then they start useing them with fragile rocks like obsidian and most softer stuff you can start with pellets in 60/90 but it does slow down the grind but it's worth it for fragile rocks --- just watch your level of rock it has alot to do with the fracturs if they bang to much even solid rocks will get hurt

Since using more plastic pellets and putting some sugar in the tumbler-charge, I have eliminated the white-dots on stones I used to get.

If stones 'fall too hard' in tumbler, you get broken and fractures.

If they 'fall just a little easier', but still too hard, you get white-marks/dots on the stones, usually more prominent on 'ends' of stones.

The idea with sugar is to thicken the water. Think of mollasses/corn syrup. By thickening the water, you cushion the stones some. It has worked out very well for me. I really love the polish I get. Add sugar (and pellets for cushion AS WELL as polishing into small areas), if you still get fractures, add more of each. Each persons 'recipe' will be different I think due to so many differences in stones. I started with equal amounts of polish-grit/pellets/sugar. And adjusted slightly as I've used them. I'll be trying/adding borax to this recipe in near future. See nice things mentioned here on this.

Some info I have heard (not tried yet), is using kerosene in place of water in the tumbler. At first, this method has 'Danger! Wil Robinson!' written all over it! Kerosene in a barrel that has a possibilty to leak, with a hot l'il motor nearby just sounds like an accident waiting to happen. However, I still think I'm going to try this method to check results. I'm going to put tumbler in a 'little-tin-shed' (ie.covered from elements) outside and try it. I wouldn't think of trying this in a house or garage. I'm planning that the damn thing WILL catch fire, and set up accordingly.

And something that I've been pondering on is Corn Starch. I'm thinking it would make a real good cushion effect. So good maybe it prevents tumbling if too much. Ever see the science experiment where the guy mixes up a bowl of white 'liquid' (water+cornstarch), you see it rolling around the bowl, then he punches! it. No splash. Cornstarch solidifies with the impact. Cornstartch will be a liquid until it is forced/apply kinetic energy to it. I'm thinking with just the right amount (which I think may be difficlt to figure out), it may make a great medium for tumbling.

The bigger the tumbler, the more chance of broken/fractures.
(stones falling from a higher distance)

The faster the RPM of tumbler, the more chance of broken/fracs.
(more energy being 'transffered' to barrel, into the stones = hit harder)

* ^ rotary tumblers, new vibe for polish coming, will try same in vibe and post results

Some of the things I've tried, and hope to try.

Hi Andrea,
As Dusty Bottoms (above) sugests thickening
I use wall paper paste to thicken up the water to a nice goopy slurry only 1 or 2 tea level spoons to a 6 1/2 lb load,
(Experiment and dont over thicken as the grinding action will thicken the mixture , a little thicker mixture helps the grinding action ,)

I also use plastic pelets (from the 2nd stage) which I find easy to float off and seperate as-
I use a kitchen sieve over a bowl or plastic container to get rid of the goop first , then wash the rocks pellets in a bowl and just pour the pellets /water through the sieve again, ( the plastic pellets float ) there you are Andrea as easy as pie!!!

I had a lot of fractures on some Ameythist and rose Quartz when I first started in fact so bad I lost all in the barrel since then I have

1 - Thickened the goop
2 - Reduced the speed to 42 RPM
3 - Started using plastic pellets

hope this helps

have a good day

jack
Yorkshire UK

umm, one of the ol' rule of thumbs for tumbling I thought was to make sure no organic material got into the barrel. Organics will get eaten by bacteria, which in turn gives off a gas, builds pressure in tumbler and you end up with leaks or popped off top.

I made this mistake years ago when beginning, leaving too much seaweed and moss on the rocks, and sher enuff, I would get leaks. Since then, I'm extremely tedious at cleaning the stone of organics before the tumble. I haven't had a leak or popped top in over 5 years (knock on wood, the tops probably just fell off all my tumblers, hehe).

What I'm wondering is if the walnut shells cause any gas/pressure problems being that it's an organic.

WilliamC, ever have any leaks? What type of tumbler?

I suggest avoiding organic material (sugar, cornstarch, etc.) -- it only takes a few yeast or bacteria, and you've got a recipe for a barrel blow-out.

For a quick slurry, instead of fillers and additions, use less water to start, about half the recommended amount for your tumbler. Just be prepared to open the barrel after a few days to add more water (and rock), if needed. A more rapid and thick slurry should prevent your fracturing problems.