Clay - for a Quick Tumbling Slurry Additive

[1dave]

Nov 27, 2016 7:38:41 GMT -7 @jamesp said:

Higher sand content left, low to right



Sticks to boots and ATV tires

Top-of-hill rich clay source a half mile thru woods behind house. Hill top clay ofter rich. Erodes slower leaving hills...
Logging road shoulder. If it sticks to the tires when damp it will work in the tumbler. Simple test criteria.

[1dave]

Nov 27, 2016 9:22:39 GMT -7 @jamesp said:

But one avatar for Dave

Not representative. Caught in a calm mood.

[1dave]

1. Collecting for tumbler:

Nov 26, 2016 6:46:16 GMT -7 @jamesp said:

Nov 26, 2016 6:09:47 GMT -7 @itumble4you said:

Nice sampling, just the tip of the iceberg? That's a heck of a turnaround time.

Lot of variety on the Rio. Been there done that place before. This time rocks were carefully selected with tumbling in mind.

Size, shape, solid, smooth, lack of patina, lack of divots. As ready to tumble as possible.
It is a tumbler's paradise.

A lot of the bigger slab size rocks have been taken. Tons of high grade tumble size rocks just waiting be collected.
Many small high grade agate/jasper/chert biscuits that could be center tapped with a hammer to 3-4 pie cut shapes. Easy fodder for the tumbler.

Wished I had taken photos of the tumble size pebble shore lines at higher fixed lake levels.
Collecting rate about one 1"-2" pebble per 3 seconds. Fill your buckets.

The wood you about have to saw. So get bigger pieces. It breaks jagged with a hammer. Messy

2. Setting up Tumbler: (What % Slurry?)

Nov 23, 2016 3:47:53 GMT -7 @jamesp said:

The rocks in the bottom of the barrel are likely not rubbing against each other at all.
Only at the top left when the avalanche begins and while the rocks roll/slide/bounce down to the right side of the barrel.
At 60% the grinding zone longer than 80% fill.
At 100% fill there is almost zero grind zone, and little relative movement between the rocks whatsoever.

With a high suction thicker slurry the bouncing and rolling action is converted to a rubbing action.
Rocks that were bouncing in a watery slurry are not rubbing so much. Rocks that roll over themselves in a watery slurry are not rubbing so much.

The motor has to work harder to move the rocks in a thick slurry because there is more friction.
The friction caused by the slurry results in more drag on the barrel and the rocks.
That drag increases grind pressure on the rocks.(a lot with a high suction slurry)

At 30 RPM that works out to 43,200 avalanches per day.
At 55 RPM 79,200 per day.

Add 60% rock fill arrangement and thicker slurry and grind times greatly increased.
Not only is the grind zone longer but a higher percentage of the rocks are in the grind zone.

At 80% fill and slurry SiC 30 broke down in about 1.5 to 2 days.
At 60% about 12 hours. So I fill to ~2/3 (66%) for daily grit additions.

3. Speeding up tumbling time:

Nov 25, 2016 23:23:10 GMT -7 @jamesp said:

Threw everything at them. Slurry,small doses coarse grit almost daily, some pre-grinding. Two clean outs. 60% fill.
Finished in turned up vibe using only AO 500 for a day, some 2 days.

Lightbox flickr link www.flickr.com/photos/67205364@N06/31230043065/in/album-72157673064411694/lightbox/

4 woods, 4 jaspers Mac contact sheet, turned sideways and cropped in flickr's Aviary photoshop



Contact sheet using Mac on solid Texas pet wood



On a multicolored but fractured jasper. [/quote]

[1dave]

Nov 28, 2016 5:35:05 GMT -7 @jamesp said:

Nov 28, 2016 5:30:18 GMT -7 1dave said:

After you answered I edited the above to ask what % slurry do you start with?

Best = 60% rocks, X% grit, Y% slurry ?

Never calculated percentages. One cup of clay to 6 pounds rock. Water about one inch below rock line at 60-70% rock fill.
70% rock fill OK at start as they will reduce to 60% fill fairly quick.
You sorta have to dial in your own machine with your clay/thickener of choice.
Clays not created equal...

[1dave]

Unscientific 46/70 grit experiment

Nov 23, 2016 15:35:29 GMT -7 @chicagodave said:

OK, so I've seen all the discussions about grit breaking down really fast in PVC barrels and the magic clay involved.  I've always wondered if 7 day clean outs were just a few days of rocks tumbling around with no grinding action.  I currently use 1/2 cup of 46/70SiC and 1/2 cup of clay based cat litter (always leads to a nice pancake batter consistency).  I fill my 6# Lortone barrels (which are rubber) about 75-80% full.  Water just below the top layer of rocks.  I always noticed a few bits of grit leftover after 7 days.  But I was chatting with @itumble4you and something he said made me want to do a little testing.  I figured I had 4 barrels that were started on Sunday.  I could test one today and then each day after.  Would there still be grit in my slurry?

So I just opened the barrel that has been running for 3 days.  Emptied the slurry into a bucket.  I don't have any scientific equipment to test leftover grit so I dunked my hand in there and began feeling around.  I was shocked to find not much grit was left.  I would even say it feels about the same as a barrel running for 7 days (yes, I have a habit of dunking my hand in slurry each week).  There was a little bit that settled to the bottom, but I'm guessing it would amount to a 1/4 teaspoon or less.

So I'm guessing I'll switch to barrel clean outs every 3 or 4 days.  If I can't feel any grit left in the slurry, the grinding action doesn't really exist anymore, right?

Nov 23, 2016 16:39:32 GMT -7 @jamesp said:

Answer is yes Dave. No more grinding, just rolling the rocks.
45/70 should be easy to feel and see. Sprinkle some fresh 45/70 on a white napkin to get an idea of what size it is.

You can pour the whole batch slurry and rocks into a light colored tub. Wash the barrel out briefly into said tub.
Pour fresh water in with rocks and slurry, and mix it around to thin your slurry.
Come back 10 minutes later, remove the rocks, pour off most of the liquid, and inspect the bottom of the tray for grit.
Grit is a good bit denser than quartz and agate and will head right for the bottom of the tray.
You can sprinkle a dash of fresh 45/70 next to the used grit to compare used to fresh.

Sounds like you are having efficient grinding. Might think about checking after 2 days.

Nov 24, 2016 5:11:10 GMT -7 @jamesp said:

Consider an increase, adding 1/3 a cup 45/70(6 pounds rock) every day for 3 days with no clean outs, then let run for 2-3 days to make sure grit is broken down, and then do a grit separation test.

Running with good colloidal clay I can go 6 days adding 1/3 to 1/2 cup grit with no clean outs. May let it run day 7 and day 8 with out adding grit to make sure all grit is done. Then clean out.
Trick is to not put too much clay to start with so slurry does not get too thick after 6 days of adding grit. Start with just enough clay to get grit circulating and breaking down.
You can always pour some of the slurry off and add water to thin slurry at daily grit additions-as needed.

I used calcium carbonate(limestone of some sort from the wild) instead of colloidal clay and it would take grit additions every day for up to 3 days. Before gelling.
Then run 2-3 days to make sure breakdown occurs.

By doing multiple grit additions WITHOUT clean outs the grit sees a lot more time in the barrel on say 5 grit additions on an 8 day run with out clean outs,
Day 2 grit sees 6 days
Day 3 grit sees 5 days
Day 4 grit sees 4 days
Day 5 grit sees 3 days
AGAIN, you can always pour some of the slurry off and add water to thin the slurry out if needed say day 3 and day 6 when adding grit. Or as needed.
This method puts a lot of time on the grit, condenses coarse grind. Rocks see a lot of time with 45 and 70 grit work horse grit.

I have tried clays from all over. They are NOT created equal. Most clay is felspar based. If you live in the east around granite geology you probably have COLLOIDAL FELSPAR BASED CLAY.
Look up kaolin, a felspar based clay, it is a very common clay around granite geology. Granite is quartz and felspar. High felspar content(kaolin) is best.

The most extreme case:
6 pound barrel
55 RPM
A single one pound rock mixed with one inch normal tumbles.
One cup clay
Half cup coarse grit
With this overly aggressive arrangement SiC 30 grit was gone in 6 hours. Well, who can add grit every 6 hours ?
And why run it 24 hours if the grit is shot at 6 hours ? So I slowed the machine to 30 RPM for one day grit additions.

The biggest pain in the but is the coarse grind, so all the experiments. The vibe does the rest of the tumble to polish in 4-6 days.
It is the coarse grind that is the problem. I was getting bored with coarse taking 12 and 14 weeks.

Nov 28, 2016 4:07:51 GMT -7 @jamesp said:

Cutting back to 1/3-1/2 cup grit every day is working. Too much grit too fast has a way of messing with the slurry.
Density of most rock shavings from quartz rocks is 2.5-2.8. SiC is 3.5 and bigger particles than rock shavings in early grind, so heavy and hard for slurry to lift. Maybe at higher speeds.

Main reason for adding a bit smaller doses of grit daily is to maintain bigger grit particles every day without too much grit accumulation.
Sometime open your barrel after 6-12 hours and do a separation in a tub.
When I dump the entire contents in a tub, I use a water hose with valve set on sharp spray, spray contents while rolling the rocks around with other hand to wash them down well.
Till tub is 3/4 full of water.
That way all the heavy grit falls to the bottom. Then let tub sit and let gravity pull all the particles settle to bottom-like over night.
Then pick rocks out by hand swishing them a bit in the cleaner water at the top to make any grit wash to the bottom. Then pour most of the water off slowly.
Then you will find out how much your 45/70 has broken down in just 6-12 hours. You may find that your slurry is working well. So well that your 45/70 is smaller than 220 in say 6 hours.
If it is 220 in just 6 hours then you are not doing any grinding for the rest of that day(18 hours). No big deal, but it is nice to know.
If you are bored and have the time you may get away with adding small doses every 8 hours.

At least you know that your grit is breaking down efficiently. Better to know. A one time test.

Cause I am amazed at how short lived any coarse SiC is with half good slurry. I have no easy solution, adding grit so often ain't fun.
And it does not hurt anything to let it roll longer if you can't add grit.

You can recapture the grit in the bottom of the little tub and put it back in the barrel if it did not break down.
Just add a little water and slush it around while pouring contents back in barrel.

Nov 28, 2016 4:17:29 GMT -7 @jamesp said:

There is no fine line between 45/70 and 220. 220 will not grind one iota off your rocks. Your 45/70 is shot.
And when dumping slurry I often see a lot of 200-300 particles in the slurry. And yes you are throwing away SiC. So what.
SiC 200-300 is useless at that point. So why waste electricity rolling it.

You can savage it if you want. How much SiC 220 do you need ? Just enough to move on to 500 step.
Might as well wait till your rocks are finished coarse shaping and then let the last 45/70 addition run for several days and it will break down to 1000 or smaller with good slurry.
That's a fact. The tumbler will scavenge every single bit of that 45/70 and crush it to about nothing. IMO, better than a thorough clean out and doing a short 220 run.

You may want to wash your cap off to remove any trapped 45/70 particles on the final 45/70 run about mid way.

Nov 28, 2016 4:50:48 GMT -7 @jamesp said:

SiC 30 in clay slurry after one hour. Note particles are spread out evenly. That is target.



Same slurry as above, scooped off TOP with hand. SiC particles well mixed and distributed about slurry. See finger tips where slurry is thinning out.

[1dave]

Sept 11, 2016 16:18:10 GMT -7 @jamesp said:

Sept 11, 2016 14:38:58 GMT -7 @orrum said:

Hey Jim how much SC 30 do you put in a 12-15 lb barrel?

Just a cup. And then another cup 3 days later. And another 3 days later. on and on.
Often do not do a clean out. Just pour water in the barrel, shake and pour liquid back out to thin slurry.
Or add water and let it roll for a few minutes and then pour liquid out if the slurry is really thick.
Let the barrel sit a minute for grit to settle and then pour liquid out.
Adding a cup every 3 days because it breaks down every 2-3 days.
So the early grit additions get run a long time.

[1dave]

Nov 28, 2016 8:16:41 GMT -7 @Deleted said:

Nov 26, 2016 13:36:22 GMT -7 @metalsmith said:

The sticky nature is due to the electro-static charges of the particles ref

No doubt the shape, chemistry and ionic behaviour are all inescapably linked. I hope you guys are signed up for PhD's...

Thanks Chas!

I was (poorly) referencing the post I made about pH changing shape of the particles from stacked deck to house of cards...

Good to know ultimately it's the charges on the clay particles setting the tone.

[1dave]

Some Tumbling Instructions:

If you are tumbling with the Thumler's Model MP-1 tumbler (which has a two-pound capacity barrel), you can follow the instructions below, but use about two level tablespoons of grit or polish in each of the tumbling steps (Step 1 through Step 4).

Tumbler rough, grit, and barrel

When tumbling you will place enough rocks in the barrel to make it about 2/3 full. Then, add about two level tablespoons of grit for each pound of rock. Finally, add enough water to almost cover the rock. Now seal the barrel and place it on the tumbler.

STEP 1 - Coarse Grind

The first step of the four-step tumbling process is to run the rocks in the tumbler with coarse grit. You begin with a barrel that is about 2/3 full of tumbling rough, then add two level tablespoons of coarse grit (we use 60/90 grit silicon carbide) for each pound of rock. Then, add water until the water line is just below the top of the rocks. Seal the barrel and run for about seven days.

At the end of seven days, open the barrel. You will find a barrel of rocks in very muddy water! Dump the contents into a screen or a colander over a plastic bucket and rinse off every speck of grit and mud. Wear safety glasses to protect your eyes from a splash of mud.

DO NOT ALLOW THE GRIT OR MUD TO GO DOWN THE DRAIN - it will clog the pipes. To avoid getting grit and mud down the drain, we wash the rocks in a colander over a plastic bucket.

Now that you have washed the rocks, it is time to inspect them. You want to determine if they are ready to move on to STEP 2, or if another week in STEP 1 would improve their appearance. This is what most people do.

However, other people want to have more control over the tumbling process and only admit excellent rocks into STEP 2. These people sort their rocks into four categories:

A) those that are ready for STEP 2
B) those that could be improved by another week in STEP 1
C) those that should be trimmed and returned to STEP 1
D) those that should be discarded

They then repeat STEP 1 until they have enough nicely shaped rocks that are ready for STEP 2. People who follow this process produce really nice tumbled stones; however, this process is very time consuming.
washing tumbled stones
Here is some rock right out of STEP 1. Note how it is covered with a gray "mud." This mud is spent grit and tiny rock particles that were worn off of the rocks during tumbling. Wash the rocks thoroughly so none of this grit goes into STEP 2. We wash our rocks in a colander over a plastic bucket so none of the mud goes down the drain.

STEP 2 - Medium Grind

The second step of the four-step tumbling process is to run the rocks in the tumbler with medium grit. Before you begin it is extremely important to clean all of the coarse grit and rock mud from the rocks, from the tumbler barrel and from the barrel lid. It is very important to avoid having a few grains of coarse grit in the medium grind step.

Again, fill the barrel about 2/3 full of rough (if you don't have enough rough, use ceramic media or some rocks that need a little more tumbling to make up the volume). Then add two level tablespoons of medium grit (we use 110/220 grit or 150/220 grit silicon carbide) for each pound of rock. Then add water until the water line is just below the top of the rocks. Now tumble for seven days.

At the end of seven days, open the barrel and clean all of the grit from the rocks, barrel, and lid (don't let any grit go down the drain). At this point in the tumbling process, a dry rock should have a smooth frosted surface. Inspect the rocks, looking for any that are cracked or broken. If found, they are discarded or saved for the next time we run Step 1.
DO NOT pour down the drain
Rock mud should never be washed down a household drain. It can clog your plumbing system. We wash over a plastic bucket to keep the mud out of the drain.

STEP 3 - Fine Grind / Pre-polish

The third step of the four-step tumbling process is a week in a fine grit such as 600 grit or 500 grit silicon carbide. Begin with a barrel that is perfectly clean. Add rough to fill it about 2/3 full, add two level tablespoons of fine grit per pound of rock. Then add water until it fills the barrel up to just below the top of the rocks. Run this for about seven days, and then do a thorough cleaning of the rocks, the barrel, and the lid. Remove any rocks that have broken or show signs of fracturing. At this point in the process, the rocks should be extremely smooth and some of them might start to have a slight luster.
clean tumbler barrel
Be very clean! Before you replace the lid on your barrel, be sure that both the lid and the rim are perfectly clean. This will allow the lid to fit tightly and prevent leaks.

STEP 4 - Polish

Now you are down to the final step - the one that puts a bright shine onto your tumbled stones. Be sure that the rocks and the equipment are perfectly clean. (Some people have an extra barrel that they use only for the polishing step.) A few specks of grit could ruin a great polish.

Place the rocks in the barrel, add two level tablespoons of rock polish (we use aluminum oxide powder or TXP) per pound of rock, add water to just below the level of the rocks. Then, close the barrel and run for about seven days.

When you finish this step, your rocks should be bright and shiny. If they are, congratulations! Admire them for a while and share them with your friends.

If the stones have an extremely smooth surface but do not shine, they might need cleaned up using the burnishing step described below. If they have scratches on them, then you will need to go back to STEP 2 and repeat the medium grind, fine grind, and polishing steps.
burnishing tumbled stones
For burnishing we chop up a bar of Ivory Soap and add 1/2 tablespoon of soap slices for each pound of rock. See our video about burnishing polished stones.
Burnishing

Sometimes our stones are a little "hazy" when they come out of the polish, or small particles of polish are in micro-size crevices. We shine and clean them up by tumbling for a couple hours in soapy water. This is called "burnishing."

To burnish we place the stones in our polish barrel with the normal amount of water and then we add about 1/2 tablespoon of chopped "Ivory" bar soap for each pound of rock (we use "ORIGINAL" Ivory soap - don't use a soap with aloe or abrasive or any other additive). Burnishing usually makes the tumbled stones a little brighter, and sometimes it really kicks up the shine.
rock tumbler log
Print a copy of our free tumbling log and use it to keep your records.
rocktumbler.com/rock-tumbling-log.pdf

Keeping Records

We recommend keeping records of what you tumble, the amount of time, the amount of grit, the amount of media, and the results that you obtain. It is easy to forget what day you started the tumbler or what type of grit was used - especially if you are running multiple tumblers. Keeping records will keep you on track and provide a history that will help you learn. We record material tumbled, start date, abrasive used, media used, finishing date and duration, along with any comments or observations about the results. To help you with your record keeping, we have prepared a printable tumbling log.

We keep records of the rock we tumble. Even if your memory is better than ours, this is a good idea. When you learn about something that works or something that doesn't, you will have it recorded. This information can help you repeat great results and avoid bad ones. Also, we have trouble remembering which day a barrel of rocks was started. With a log we can be reminded with a glance.

New Method of Tumbling (From 1996)

New Method of Tumbling - by Al Nutile in Tulip City Conglomerate

The writer believes that the following idea can take much of the work from the popular method of tumbling.
All of the instructions we have seen state: “Wash stones and tumble very clean between each change of grit or final materials,” at the same time stating, “If liquid is too thick add some slurp or grit from previously used material.”

We know some will argue against our method, but here goes:
Don’t wash at all after each week of tumbling with grit! Start with #50 grit, tumbling a week. Then DON’T EMPTY THE TUMBLER, but add 5 teaspoons of new grit [one step finer] to the mixture in the three pound tumbler. Follow this procedure through #190, #320 and #600 grit.

Now [finally] thoroughly wash the stones and tumbler before pre-polish and final polishing.

For a really glossy finish, take one or more weeks [after washing out the polishing powder] adding three spoons of sugar, one spoon [level] of Cascade or All or any non-sudsing detergent and add about ten drops of muriatic acid, if you have some, let stand one minute - open, close tub, and tumble for a week.

We have run eleven tubs using this method and found that even ordinary sandstone comes out highly glossed.
Except for extra final steps, you save three washings and getting rid of the slurp each time. Saves time, work and mess, and still gets a better polish.

From Pickin's & Diggitis 7/96
via Rock Chips 6/00 & others

Now from @jamesp : (correct my guesses)
1. Selecting and shaping rocks - cuts down on tumbling time

2. Loading the tumbler - 60% rocks, 1/2 a cup 45/70 SiC, One cup of clay to 6 pounds rock. Water about one inch below rock line at 60-70% rock fill, adding 1/3 a cup 45/70(6 pounds rock) every day for 3 days with no clean outs, then let run for 2-3 days to make sure grit is broken down, and then do a grit separation test.

Running with good colloidal clay I can go 6 days adding 1/3 to 1/2 cup grit with no clean outs. May let it run day 7 and day 8 with out adding grit to make sure all grit is done. Then clean out.
Trick is to not put too much clay to start with so slurry does not get too thick after 6 days of adding grit. Start with just enough clay to get grit circulating and breaking down.
You can always pour some of the slurry off and add water to thin slurry at daily grit additions-as needed.

By doing multiple grit additions WITHOUT clean outs the grit sees a lot more time in the barrel on say 5 grit additions on an 8 day run with out clean outs,
Day 2 grit sees 6 days
Day 3 grit sees 5 days
Day 4 grit sees 4 days
Day 5 grit sees 3 days
AGAIN, you can always pour some of the slurry off and add water to thin the slurry out if needed say day 3 and day 6 when adding grit. Or as needed.
This method puts a lot of time on the grit, condenses coarse grind. Rocks see a lot of time with 45 and 70 grit work horse grit.

I have tried clays from all over. They are NOT created equal. Most clay is felspar based. If you live in the east around granite geology you probably have COLLOIDAL FELSPAR BASED CLAY.
Look up kaolin, a felspar based clay, it is a very common clay around granite geology. Granite is quartz and felspar. High felspar content(kaolin) is best.


The most extreme case:
6 pound barrel
55 RPM
A single one pound rock mixed with one inch normal tumbles.
One cup clay
Half cup coarse grit
With this overly aggressive arrangement SiC 30 grit was gone in 6 hours. Well, who can add grit every 6 hours ?
And why run it 24 hours if the grit is shot at 6 hours ? So I slowed the machine to 30 RPM for one day grit additions.

The biggest pain in the but is the coarse grind, so all the experiments.

3. Finish with vib -The vibe does the rest of the tumble to polish in 4-6 days.
It is the coarse grind that is the problem. I was getting bored with coarse taking 12 and 14 weeks.

[1dave]

Nov 28, 2016 11:31:42 GMT -7 @txrockhunter said:

This may have been posted somewhere else, but it looks like Covington has developed a grit carrier with very similar properties.

[1dave]

Nov 28, 2016 11:59:45 GMT -7 @jamesp said:

Montmorillonite = red clay of specific composition. Note aluminosilicate of sodium. Iron.

Color = Brick red (betcha it is due to iron)
Covington is in Redland California. They don't hold a candle to Georgia red clay haha.

The South will rise again !! Dang Californians are trying to steal our red clay !!

Very good @txrockhunter

If my neighbors found out they could sell their red clay for $33.75/5 pounds they would puke.

Assume Georgia red clay has more than 2% silica. But may have way more colloidal particles due to kaolin.

[1dave]

Nov 28, 2016 15:20:08 GMT -7 @jamesp said:

Nov 28, 2016 12:38:55 GMT -7 @shotgunner said:

Clays come in a few species.

Kaolin
Montmorillonite
Ilminite (micaceous clay)
Chlorite group


Based on my research I think only kaolin and certain forms of montmorillonite will work. I don't believe the others have the electrical properties we desire. I may be proven wrong.

Very interesting. I freaked when Jeremy posted a clay sold just for tumbling.
From Redlands of all places.

Billions of tons of kaolin used for suspicion agents, no problem there. Montmorillonite a new one on me, must research.
If able to wade thru the technical jargon, clay complicated.

You guys have kaolin too (kitty litter mine).

[1dave]

Nov 28, 2016 18:54:03 GMT -7 @jamesp said:

Typical clay depth of north Georgia.

[1dave]

Nov 29, 2016 9:04:13 GMT -7 @jamesp said:

Nov 29, 2016 4:28:35 GMT -7 1dave said:

Not very many tumbles from that layer.

What size barrel is required for a 6 pound load - 60% fill? Best length and diameter?

Here is a flickr link of the 6 pound barrels.

I stuffed the cap end side with 1/2 inch PVC sheet to protect wear.
Not required and hard to find the sheet. Butcher block could be substituted.

I liked the(gray) Carlon electrical conduit couplings, shorter and cheap.

www.flickr.com/photos/67205364@N06/sets/72157672945278964