Could there be a downside to using ceramic pieces?

[Bob]

I'm now in my 7th year of rotary tumbling.  It wasn't long into it, before I learned of those non-abrasive white ceramic pieces sold by lapidary suppliers and that they are often used instead of plastic beads by many tumblers these days, the reason given was because of how no grit gets embedded so these pieces could stay with the rocks through all grit stages and not have to be culled out.  I had used plastic beads for almost a year in the finer grit stages, so I bought some ceramics.  Not cheap either I noticed.

Did they work?  Yes  Did they work better than plastic beads?  I don't think I noticed any difference, except in grits larger than 220.  I didn't really care about being able to leave them with rocks in successive grits because I just didn't and still don't really do things that way.  I didn't need that feature because my rinsing and sorting processes are pretty efficient and fine-tuned.  And, I noticed those ceramics grind away too and that buying them would be an additional expense, and one more frequent by far than replacing plastic beads which last months and months and maybe even a couple of years.  So I sorta wanted to deemphasize using these ceramics.

I had noticed that plastic beads hinder grinding action for grits larger than 220, so I did keep some ceramics on hand for those rare occasions when I needed cushioning for delicate materials in say 80 grit.  But that wasn't very often.

About a year ago, I started processing a lot of delicate macro crystalline quartz varieties, aventurine, amazonite, obsidian,  glass, and some other types that I think do better with some cushioning in rough grind.  So, I bought 50lbs (which helps with the per lb pricing of course) of ceramics because I have a lot of this to process and they have worked fine.  However, I am surprised how fast they seem to grind down.  I have only been using the large ceramics, 3/8x3/4" I think they are.  The smaller ones just grind to nothing too fast for me.

So I looked up the Mohs and it appears that's it's probably around 7, just like most of what we process.  So, what I'm thinking is this--except for the not having to pull them out for each grit stage for those who like that--these ceramic pieces are mostly just a bucketful of almost white quartz rocks of a very convenient size and easy to grab a handful and put in loads.  But, we have to pay for this convenience as they grind away just like any other smalls we use.  Plus,  no keepers end up from them like we do with some of our trashy smalls from time to time.  You, like me, may from time to time check out your otherwise sacrificial smalls in the finer grits and find some pretty keepers that took a while to happen because so much of the cracks and pits had to be ground away first.

But, there is more I want to throw out there for the opinions of others.  Let's say we use plastic beads with 220, or 600 grit stages.  I don't think these beads being plastic use up grit, so I like to think all the grinding is against our rocks.  But, if we use ceramics instead, they are more or less just rocks we threw in too, Mohs 7, so they use up grit in and of themselves and this is what bugs me a little bit.  That's why I don't like to use them unless I have too.  (Based upon recent recommendations from others in some threads, I will admit they have helped do a bit better grinding action in 220 and 600 for glass and obsidian, so I regard that as kind of a special circumstance.)

So, I wonder if in the end, expect for special circumstances, these ceramics are really just:

1.  A convenient source of uniform-sized smalls that we can grab in our hand as easy as grabbing popcorn from a bag when we are lazy and want to have smalls within ready reach or don't have enough rock smalls.
2.  Less damaging smalls which we needs at times when a) we have already knocked off the rough corners of the ceramics in a prior  load and b) we don't for some reason want to toss in any smalls with rough edges and pits and that's maybe all we might have on hand that aren't ceramics.

If my thinking is right, and it may be very wrong, most the time ceramics may be costing us money to buy, as well as just accelerating grit consumption in loads that take away from grit grinding against the targeted rock material.  This  has been on my mind for a couple of years now.  Shipping ceramics also costs more than plastic beads because of the weight.

[EricD]

I only use ceramic in AO 500 and polish for exactly the reason that in those grits they do not lose mass (or almost no mass) and I will never need to buy more.

Well, maybe 10 years from now I will...

And they are already polished, so they aren't really using any grit.

In any other grit I just use small rocks, and not even necessarily very hard ones, either.

[HankRocks]

Used Ceramics for a couple of months but switched to Pea Gravel as a cheaper alternative. It is only used for a Run of Slabs/Pendant Preforms or a Run of Arkansas Quartz. In most cases for the Slab/Pendant Preform run I usually have enough trimmings from the Preforms to add and only add the Pea Gravel to make up any difference. For the Quartz I happen to have come into possession of about 3 gallons of small Apache Tears that I use as the smalls. On the Quartz I usually make a couple coarse runs to get enough material to move to the later stages. 

I did use Plastic Pellets for a short time, but decided that they were a pain to mess with so I dis-continued their use.

I never add any Pea Gravel to a normal run of Agate, Jasper or Wood. Try to have a size balanced load, but sometimes not. Have a load of Petrified Wood in Pre-polish that has no smalls at all and everything is in the 3/4" to 1.5" range with a  few larger

The only time I add Pea Gravel to a Agate/Jasper?Wood run is for Polish as I am moving from a 15 pound Thumlers B to an UV-18 Vib machine. I end up adding about 3 pounds of previously Pea Gravel.

[rmf]

What @hankrocks said about pea gravel. I also use previous fines. I had a customer that wanted me to cut some cabs from broken china plates. I got the ugly scraps which I broke up and used as ceramic pieces. they worked fine but yes the grind up. That is why for normal agate and jasper I fill with pea gravel. I have also tumbled a material that to get a good polish I had to mix 50% plastic pellets and 50% indoor - outdoor carpet pieces to get a good polish on varing hardness. I think jamesp does a lot of glass and uses ceramics for that so you just have to figure out what your batch needs. I have also tumbled with wooden pegs in polish.

[EricD]

Don't get me wrong, I like ceramic media. But it has only one purpose for me; pre-polish, which for me is AO-500, and polish.
I am sure once I have enough small quartz gravel and saw scraps rounded and ready, I may never use it again except for with obsidian or glass.

Starting out with slick, polished smalls is very important in the pre-polish and polish stages for a nice shine on the target stone for me. The grit (not even grit in the sense of ones like SiC, it's AO I am using) *becomes more focused* on the rougher stones because there is more friction between them for a time, but is distributed by the ceramic. Ceramic meets that need for me.

You can use either ceramic or small hard rocks for your media. You won't be able to tell a difference.

However, if you use ones that haven't become shiny yet, or are not mohs 6-7, you will need to tumble them for extra time to shine up everything. Not just a few, well maybe several, rocks.

[Bob]

Someone's comment about plates really gave me a neat idea to lower cost of ceramic pieces to almost zero. There are many thrift shop and a Habitat Restore near me. I seem to recall seeing literal piles of dinnerware for 10 to 20 cent per plate. Maybe shattering one of those on purpose would make a lot of ceramic pieces. I certainly remember vividly what happens upon dropping a Corelle plate. It virtually explodes into hundreds of shards, though I think it's a form of tempered glass rather than ceramic.

[EricD]

I don't get why anyone would balk about a few pounds of ceramic media when it literally doesn't ever wear out if used with light grits.
The coarse grits are a place you don't need to use ceramic.

[Bob]

I hear you, and I'm prepping some pieces now to use with 600 and 1,000 amethyst, obs, and glass.

[jamesp]

Dec 2, 2020 18:13:55 GMT -5 rmf said:

What @hankrocks said about pea gravel. I also use previous fines. I had a customer that wanted me to cut some cabs from broken china plates. I got the ugly scraps which I broke up and used as ceramic pieces. they worked fine but yes the grind up. That is why for normal agate and jasper I fill with pea gravel. I have also tumbled a material that to get a good polish I had to mix 50% plastic pellets and 50% indoor - outdoor carpet pieces to get a good polish on varing hardness. I think jamesp does a lot of glass and uses ceramics for that so you just have to figure out what your batch needs. I have also tumbled with wooden pegs in polish.

I use quartz pea gravel rmf.
Ceramics kept in good condition do a great job.
If one gets broken during process i would worry that in might scratch easier than quartz. But I can't prove that.
Ceramics are hard, like Mohs 8+. That is why they last so long.

Main reason for quartz - ceramic itself is so hard I think it is slow to polish as opposed to quartz media.
The media has to polish if you want the target rocks to polish.
Try running unpolished ceramic media with polished rocks without abrasives - the polished rocks will become unpolished in a big hurry.

If you don't add 25 to 50% pea gravel or ceramic when doing Mohs 5 glass it takes forever for aluminum oxide to break down in the vibe. Glass is a sucky media for aluminum oxide, it is too soft.
Best to use Mohs 7(quartz/agate) to Mohs 8(ceramic) media to break down Mohs 9 abrasives.

(Efficient)rock tumbling = The abrasive break down game.
That is why rocks can go from rough to bright polish in 2 grit steps.

ETA I say never use plastics. They can't help but retard the grind.
It takes long enough to tumble rocks to be adding materials that prevent rock to rock to hard media contact.
Granted for softer materials they may be totally necessary.
Mohs 5-6-7 I think they are a waste of time and space.

[jamesp]

Dec 2, 2020 19:55:42 GMT -5 EricD said:

I don't get why anyone would balk about a few pounds of ceramic media when it literally doesn't ever wear out if used with light grits.
The coarse grits are a place you don't need to use ceramic.

yep, totally counter productive.
Ceramics used during coarse stage makes me cringe Eric.
They are just wearing out valuable coarse silicon carbide abrasive and your costly ceramics.
Maybe for soft materials for filler or to help break down coarse silicon carbide to say 220 grit for soft materials.

[Bob]

Eric, I have now had two batches of ceramics run with glass, obs, and amethyst in 600. Each were 6lb barrels and because I'm being gentle, half is filler/cushioning and sometimes I will run several weeks at the same grit to ease out scratches gradually. Both of these batches were used with ceramics instead of plastic pellets. With half plastic pellets and 600, there is almost always some grit left after a week so I usually run 10 days. This didn't happen with the ceramics. Also, the grinding action seemed to be a little superior too judging by the rock surfaces especially the edges of those annoying fractures in amethyst. So I'm sold so far on your method and 1,000 will be done soon too.

To knock off the rough corners of the ceramics for 600, I let them spend a week in 220 first with rocks which seems to make them about right. I suppose I could have saved more of my ceramic pieces sizes though by not doing that, and instead running just a barrel of ceramics alone in 600 just to smooth them up enough. I'll try that next time. And I have prepped ceramics for 1,000 by first making sure they were run in 600. So I'm building up a supply of ceramics to be dedicated to only run in 600 and another to only run in 1,000.

[electrocutus]

Dec 2, 2020 19:55:42 GMT -5 EricD said:

I don't get why anyone would balk about a few pounds of ceramic media when it literally doesn't ever wear out if used with light grits.
The coarse grits are a place you don't need to use ceramic.

Wow, I'm learning so much from this thread.
I only have a few batches of tumbling under my belt, but my thinking was that I should use ceramic media in the coarser grinds (second step to make up the lost volume from the first stage), and then use plastic pellets in the pre-polish and polish. My thinking was that plastic pellets would be gentler to the stones in the polishing. 
It sounds like I have it all wrong?!?!


So, what I'm reading here is that it's better to use ceramic only in the pre-polish and polish stages?

I'd love to use left over polished smalls as filler, but I don't have enough of that yet. I'm also suffering from newbie syndrome and I can't think yet of "sacrificing" the little tiny ones as just grinding material! :-) 

What if I am trying to tumble soft stones (4.5-5)? I only have medium-size rough stones (1 -2 inches), and not enough to fill my small barrel. What would you recommend I add to each stage of my grinds and polishes?

[Bob]

Tumbling soft stones as you describe is problematic on many fronts. If you can, don't do it at all. If you have to, do it after you have more experience.  Apatite, chalcosiderite, gaspeite, kingstonite, variquoise, varisite, larimar, and other stones in that Mohs range are very unique challenges often requiring special methods and frankly not good for general tumbling.

[EricD]

Dec 10, 2020 13:34:39 GMT -5 Bob said:

Eric, I have now had two batches of ceramics run with glass, obs, and amethyst in 600. Each were 6lb barrels and because I'm being gentle, half is filler/cushioning and sometimes I will run several weeks at the same grit to ease out scratches gradually. Both of these batches were used with ceramics instead of plastic pellets. With half plastic pellets and 600, there is almost always some grit left after a week so I usually run 10 days. This didn't happen with the ceramics. Also, the grinding action seemed to be a little superior too judging by the rock surfaces especially the edges of those annoying fractures in amethyst. So I'm sold so far on your method and 1,000 will be done soon too.

To knock off the rough corners of the ceramics for 600, I let them spend a week in 220 first with rocks which seems to make them about right. I suppose I could have saved more of my ceramic pieces sizes though by not doing that, and instead running just a barrel of ceramics alone in 600 just to smooth them up enough. I'll try that next time. And I have prepped ceramics for 1,000 by first making sure they were run in 600. So I'm building up a supply of ceramics to be dedicated to only run in 600 and another to only run in 1,000.

Good to hear you are having a positive experience.

I like the edges of my ceramic as round as I can get to begin with (week in 80ish grit in the rotary with some rocks).

Then the stuff is good to go for a long long time.

Dec 10, 2020 14:46:21 GMT -5 electrocutus said:

Dec 2, 2020 19:55:42 GMT -5 EricD said:

I don't get why anyone would balk about a few pounds of ceramic media when it literally doesn't ever wear out if used with light grits.
The coarse grits are a place you don't need to use ceramic.

Wow, I'm learning so much from this thread.
I only have a few batches of tumbling under my belt, but my thinking was that I should use ceramic media in the coarser grinds (second step to make up the lost volume from the first stage), and then use plastic pellets in the pre-polish and polish. My thinking was that plastic pellets would be gentler to the stones in the polishing. 
It sounds like I have it all wrong?!?!


So, what I'm reading here is that it's better to use ceramic only in the pre-polish and polish stages?

I'd love to use left over polished smalls as filler, but I don't have enough of that yet. I'm also suffering from newbie syndrome and I can't think yet of "sacrificing" the little tiny ones as just grinding material! :-) 

What if I am trying to tumble soft stones (4.5-5)? I only have medium-size rough stones (1 -2 inches), and not enough to fill my small barrel. What would you recommend I add to each stage of my grinds and polishes?

I don't use my rotary for anything other than grit around 80.

I don't think using ceramic in any grit coarser than ao500/SiC 1,000 (anything that really wears on it) is cost effective or provides a better outcome.

That's pretty much what I was getting at.

And yes, pre-rounded / polished ceramic or agate/jasper smalls are a good replacement for rock mass in your finer grit stages. Good "cushioning" as well.

Even for softer stones. My best ever polish on obsidian and glass was with ceramic that was pre-polished.

[HuntingHuron]

I just want to be clear on the use of plastic. Am I hearing it correctly  - they shouldn't be used for the pre-polish (i.e. 500 SiC) ? Would they interfere with the process for that particular stage?

[Bob]

Eric, an update. I have now had several batches of obs and glass (with a little bit of delicate amethyst) complete using ceramic pieces, enough in 80 and 220 to form some impressions, not enough in finer grits yet though.

I'm seeing a bit of breakage and damage, but not much, maybe 5% max. But I'm seeing more grinding getting done. And something that used to happen isn't happening anymore. I used to be surprised to find a lot of unused grit in the bottom of the barrel when I was using plastic pellets, so I would reseal the barrel and run 3-4 more days. In fact, with obs and glass I just mostly switched to a 10 day run instead of normal 7 because of that. That doesn't happen anymore. So so far so good and liking your ideas.

[titaniumkid]

Instead of starting a new thread, I thought it would be better to post this here as it seems very related.

I've noticed a lot of cracked and broken pieces of ceramic media. I think it has to do with the shapes of the ceramic media I used. I was under the impression a variety of sizes is good, but options were limited so I ended up buying ceramic media recommended for tumbling that came in a mix of shapes (circles, pyramids, and cylinders) and sizes. Many pieces have worn flat quite quickly, which has then made them prone to breaking into pieces. I suspect a combination of rotary tumbling, ceramic shapes (the pyramids seem most susceptible), and smaller pieces getting stuck on the sides during tumbling has caused uneven surface wear.

It was somewhat annoying because I've now had to pick through ceramic media to ensure damaged or flat pieces are not going into my final pre-polish or polish stages to scratch things up. Such pieces will be used in future coarse grinds.

I like the idea of using tiny rocks rather than ceramics (tiny polished rocks are some of my favourites), but I need to find something readily available here. The pea gravel I've seen tends to be porous.

Anyway, I thought I would share this experience.

[chris1956]

May 22, 2024 19:33:03 GMT -5 titaniumkid said:

Instead of starting a new thread, I thought it would be better to post this here as it seems very related.

I've noticed a lot of cracked and broken pieces of ceramic media. I think it has to do with the shapes of the ceramic media I used. I was under the impression a variety of sizes is good, but options were limited so I ended up buying ceramic media recommended for tumbling that came in a mix of shapes (circles, pyramids, and cylinders) and sizes. Many pieces have worn flat quite quickly, which has then made them prone to breaking into pieces. I suspect a combination of rotary tumbling, ceramic shapes (the pyramids seem most susceptible), and smaller pieces getting stuck on the sides during tumbling has caused uneven surface wear.

It was somewhat annoying because I've now had to pick through ceramic media to ensure damaged or flat pieces are not going into my final pre-polish or polish stages to scratch things up. Such pieces will be used in future coarse grinds.

I like the idea of using tiny rocks rather than ceramics (tiny polished rocks are some of my favourites), but I need to find something readily available here. The pea gravel I've seen tends to be porous.

Anyway, I thought I would share this experience.

I have only used the ceramic cylinders.   I don't recall any of the bigger cylinders breaking until they got really worn down (they do tend to get flat).  The smaller cylinder ones, like Bob mentioned, break quickly (and really are a mess to separate out).   If you don't have tiny small hard rocks that you can gather, you might try aquarium rock (has to be harder rock) sold in stores like Walmart (I haven't tried this but someone on the forum suggested it somewhere).   I typically take all the scraps from sawing shapes and add those to the mix starting with 80 grit and then moving them on as they get worn and polished.   That seems to work well at least for me.

[chris1956]

Now I am not sure if it was aquarium rock or real small landscape rock.  Someone will know.  

[miket]

I use ceramics now but I used to just collect pebbles when I was out hounding.
A good option if you want to take the time to gather them...