1st. Stage Tumbling: Sand OK?

I have used finely crushed stone to remove some softer material from agate. It worked pretty good. My guess is that you would be able to round off some sharp edges and such, but you will still need to start with a course grit to ensure a good polish in the end.

Hi Racoon, welcome aboard. I do think it would be wise to remove the sand before going to grits. You have already rounded the rocks some and you have also rounded the sand grains. No point in wasting grit making little grains out of bigger ones. Brad

If the rocks are already rounded the sand won't do much of anything. It was sand and other rocks that rounded them. To further round them off quickly you'll need something harder than the rocks like silicon carbide. And, if you like the beach rounded condition you can skip the first step.

Hi
I Agree with John above

Why waste power on using a soft sand on Hard rock ? Just Think what is going on inside that barrel ? !!
hit em hard with some SC 80 G !!

Have a good day

Jack
Yorkshire UK

Rollingstone and Jack--Thanks. Good info. Rollingstone's comments have me thinking about the relative hardness and qualities of rock and mineral. Especially interesting was the difference in how they breakdown: jagged vs. round.

Hi Racoon!

Good to see more new members in th PNW area, i'm just across the water on the Canada side, southeast end of Vancouver Island.

Ya just GOTTA love the beach huh, always a good place to find tumbler ammunition.

Some of the inland members may not be keen to this procedure because they make be used to tumbling quarried stone but sand can be used as a good medium for pre-cleaning those rocks you find on the beach before tumbling them in grit.

Beach stones are usually laiden with some amount of organic material accumulated on them. Organic material can decompose and produce offgassing from the rock over time which can lead to bulging/bursting barrel syndrome, quite messy if not caught in time.

Because of this, it's a good idea to elliminate as much residual organic material as possible from the stones before the grit stage, in what is commonly called a burnishing cylce. You essentially fill the barrel to the right level with rinsed rocks, add a teaspoon of borax powder and a tablespoon or more of sand per pound of rocks. Let this concoction roll for a couple of hours then the rocks will be scrubbed clean enough by the sand to rinse and roll without having to "burp" the barrel as much or at all during the grit stages depending on the material.

Past this, putting a tablespoon of sand in at the beginning of the coarse grit stage can help build the surry somewhat faster which will slightly improve the grind time to shape them. A larger amount is not needed or recommended since the slurry can end up being too thick after some time and the sand will also eat a little bit of the grit while breaking down.

After the grit stage sand will only interfere with your finished result so don't use it beyond the coarse grit. When you need volume filler or cushioning material you can use plastic &/or ceramic pellets. Silica sand is sometimes used as a dry medium to tumble other things for an abrased look but that's a whole different story...

Racoon, if you are on the Olympic penninsula, you might want to keep an eye out for the poppy jasper pebbles that are sometimes found on the beaches there. I gather it is rather rare, and is only known from rounded beach stones, ie the source has never been located (may have been completely eroded away). I bought some rough on ebay a few years back, and it is a great looking stone and takes a nice polish. The seller said it had been collected on the beaches of the Olympic penninsula some years ago. Here's a couple of polished pics:

I have found a few pieces of that Olympic Poppy Jasper over here but I do agree that it is quite a rare find, at least over here anyway. "My secret beach" faces directly toward the Olympic Peninsula so I probably have as good a chance of finding some as anyone over there unless the source is located closer to that side.

It's the same story with the Dallasite that is found here, nobody really knows where the main source is, it's only found on beaches and no land based source has been claimed for it since it was first recognised as a distinct locally occuring stone back in the early 70's. It is actually named after Dallas Road which overlooks the stretch of beach near downtown Victoria where it was first collected.

Over the years I have found a few pieces of Oregon Moss Agate on beaches here so I never discount the possibility that a nice stone or two from a far away place will eventually wash up here for me to find.