Ball milling glaze

[docweathers]

I have heard varying opinions about whether one should ball mill most glazes. Do you find it worthwhile? What benefits do you observe?

[AtomicAxe]

Depends on your own glazing practices .. I made my ball mill to make terra sigillata and reclaim 90-95% of the clay used to make the fine particles as opposed to 40-50% ... but when I also make slips, underglazes, and any sort of even glaze that I know has heavy particles ... I will ball mill it just to make them a little more suspendable in the glaze. Granular glazes, ash glazes, things with a certain level of unpredictability ... nah ... just jiffy mix every other dip.

 

Also I'm in the process of trying to break down quartzite into quartz granuals so I can suspend them into a glaze and get the soft silica nubbins on more sculptural work. ... that requires a way to break down quartzite and a ball mill.

 

I also will stick reclaimed glass in my ball mill (broken down into small pieces and any glass dust with it ... and my milling media and try to make glass dust and glass particles ... the dust I can mix with feldspar and clay and make a fast glaze (nothing for overly functional work ... just accent glaze stuff), the more granular glass I will save so when I dip a larger piece, when the glaze is wet I can sprinkle some on and cause some flashing much like a wood kiln ... only more runny (so use sparingly). and the larger hunks are normally polished glass that I will either give to some local crafters for usually bead work or I will save them for next time, break them down some more and run them through the mill again. Especially with different bottles entering the market ... you can experiment or mix and match ... for a while all I used was green glass from beer bottles and clear glass from a local glass shop that did window panes.

[neilestrick]

Most glazes do not require milling. It can even cause application problems with some glazes. However flashing slips and terra sigs benefit from the smaller particle sizes.

[OffCenter]

What a profile picture, AtomicAxe. I wouldn't want to meet you in a dark alley.

 

Jim

[Marcia Selsor]

I have an old home made ball mill . I use to use it for terra sig, but I don't use one for terra sig anymore. I use Charlie Riggs method and don't need one.

I had some use for one when I was doing crystalline glazes in the 70s, but not that many of them required it either.

 

Marcia

[M. Hogsed]

What a profile picture, AtomicAxe. I wouldn't want to meet you in a dark alley.

 

Jim

 

 

 

Now that's the funniest thing I've read all morning. What a profiile picture, OffCenter. I wouldn't want to meet you in a dark alley either!

 

 

Marcia H.

[Mark C.]

I do not use one and have not since the 70's. I do use 300 mesh silica instead of 200 mesh.-Makes for a better melt.

Mark

[Chris Campbell]

I attended a workshop with David and Margaret Frith, potters from Wales about ten years ago. He ball mills all their glaze ingredients. He thought it produced better glaze melt. They were able to lower the temperature of the firings significantly. I am remembering it was by one or two Cones. He also processes all his own clay so is able to balance that maturation temperature so it all fits.

[Marcia Selsor]

I attended a workshop with David and Margaret Frith, potters from Wales about ten years ago. He ball mills all their glaze ingredients. He thought it produced better glaze melt. They were able to lower the temperature of the firings significantly. I am remembering it was by one or two Cones. He also processes all his own clay so is able to balance that maturation temperature so it all fits.

 

 

That is interesting ..and nice examples of their work. I hadn't really thought about the milling to lower the melt before. Always something new and exciting to learn in Ceramics!!! Thanks, Chris.

 

Marcia

[Mark C.]

Smaller particles melt with less heat-thats why the 300 mesh silica has different results that say the 200 mesh at a given temp.

I switched over long ago.-Many clay bodies use 200 mesh silica as its also I think a little cheaper.

Mark

[docweathers]

I will switch to 300 mesh silica as soon as I use it my 200.

[Round2potter]

And if you have a ball mill you can play with all sorts of fun materials around your home, like gather and process your own glaze ingredients.

I recently ball milled some basalt rich sand i gathered for about three days and got some nice results firing to cone ten in an electric but worse in reduction.

So i cut it with feldspar and clay in a small series and got a gorgeous Temmoku-like brown with nice breaks.

[Guest JBaymore]

One of my standard glazes is mostly local crushed granite, ball milled for 6 hours.

 

best,

 

.....................john

[AtomicAxe]

Quartzite are those quartz garden stones that look white(ish to dark brown), but when broken are really are quartz sand that has been heat fuzed and tumbled ... little pounding and you will in essense have granular silica so mixed with a proper feldspar, kaolin mix, would produce an eerie glaze in theory.

 

 

So, I picked up some quartzite and broke some apart into a rough state, did not take that much work or force either so a proper tooling and grinding technique will result it almost a usable material. End result will be to have granular quarts around 80-100 mesh with a byproduct of quartz powder that should be siftable.

 

Quartz is mainly a composite material consisting of silica dioxide and/or silica tetra-oxide and trace minerials of rutile, iron oxide, magnetite (granular iron oxide basically), and zircon.

 

Quartzite can be man made or naturally occuring, with the naturally occuring being sedimentary in origin.

 

Quartzite has a lower melting point than more pure sources of silica ranging from 2400-2900*F

 

 

In theory, larger particles that will be considered 'granular' in a glaze will not fully melt, and will instead appear as soft dimples on the glaze.

 

 

 

 

Alrighty, so with production and refinement of raw quartzite under way (little tedious without a proper rock crusher) ... here will be my first 4 initial test glazes using this raw material.

 

 

 

 

 

TEST 1

 

 

 

Quartz ... 25

 

 

 

Feldspar ... 30

 

 

 

Whiting ... 10

 

 

 

Ball Clay ... 20

 

 

 

Gerstley ... 5

 

 

 

Talc ... 9

 

 

 

Bentonite ... 1

 

 

 

TEST 2

 

 

 

Quartz ... 25

 

 

 

Neph Sy ... 30

 

 

 

Whiting ... 10

 

 

 

Ball Clay ... 20

 

 

 

Gerstley ... 5

 

 

 

Talc ... 9

 

 

 

Bentonite ... 1

 

 

 

TEST 3

 

 

 

Quartz ... 25

 

 

 

Feldspar ... 35

 

 

 

Whiting ... 10

 

 

 

Ball Clay ... 20

 

 

 

Talc ... 9

 

 

 

Bentonite ... 1

 

 

 

TEST 4

 

 

 

Quartz ... 25

 

 

 

Neph Sy ... 35

 

 

 

Whiting ... 10

 

 

 

Ball Clay ... 20

 

 

 

Talc ... 9

 

 

 

Bentonite ... 1

 

 

 

Now, as per the chemical properties of what is needed in a glaze, with a lower melting point of the quartzite and the increased feldspar, this should result in a successful glaze that bonds to the body. The granular quality of the quartzite should also provide a more rippled surface as the flux will interact with the surface of the granular quartz (sand? grain?) and the impure nature of the quartzite will create a more brown to purpleish glaze from the trace elements of RIO, Manganese, Rutile and Zircon that forms with quartz.

 

 

My goal:

 

When I am able to crush enough of the material ... I will ball mill out the raw material and be able to achieve 2 different materials. Fine grade quartz and more granular quartz. The fine grade quartz I am going to test as a primary replacement to silica and the granular quartz can be an additive to just about any glaze since the melting range is at or above cone 10 and sources of flux in the glaze will not fully melt a thicker material such as this.

[Round2potter]

AtomicAxe, that is quite a sweet little series of tests you have going! I am a geology major in school and this seems a slightly odd choice of minerals to gather for a glaze.

 

Let me stress though, that no matter how "weird a choice" i might think it is, ROCK ON MAN (get it...) keep up the testing!!!

 

Now I will add my 2 bits; look for other, much softer, minerals in your area, Quartzite is a metamorphic rock that is in essence compressed sandstone, which being mostly quartz, is very hard and difficult to process.

 

So, my question is, Are there streams or rivers nearby that you have access too? What is the area like? is there any type of rock that is abundant in the landscape?

If you are gathering quartzite than you will most likely find what used to be quartzite in the form of sand/clay deposits.

Or look around for things like Gneiss and granite or basalt; most of these rocks are softer than (almost) pure quartz.

 

Cheers!

-Burt

 

Oh, and to tie this in to the thread a little bit; using softer materials saves on milling time, wear and tear on equipment, energy costs, and it increases the amount of material you can process at once and over a period of time.

[AtomicAxe]

I actually chose quartzite for a reason, the commercial version is actually a mechanically processed stone for gardens and road ways ... in my local area (nearest couple hundred miles) I know they mine for quartz, and as such all the residual quartz sand, debris and what have you actually goes into manufacturing these stones ... it's heat fused to a sheet, broken then tumbled with smaller pieces reclaimed for further manufacturing. The 'rock' at this point is rather soft to break and I am working on making a rock crusher that is composed of 2 ground pampers facing each other with side skirting to avoid shooting rock all over the place, I manually hammer with a hand held sledge and it crushes the rock rather easily into what I have shown in the photo of my hand. I will also be using my modified pampers (for originally laying patio brick) to also crush glass into small pieces without debris shooting everywhere. It will be much easier than my current process for breaking down glass (metal bucket and dropping a sledge hammer on it till it is mostly small pieces)

[Ben]

I actually chose quartzite for a reason, the commercial version is actually a mechanically processed stone for gardens and road ways ... in my local area (nearest couple hundred miles) I know they mine for quartz, and as such all the residual quartz sand, debris and what have you actually goes into manufacturing these stones ... it's heat fused to a sheet, broken then tumbled with smaller pieces reclaimed for further manufacturing. The 'rock' at this point is rather soft to break and I am working on making a rock crusher that is composed of 2 ground pampers facing each other with side skirting to avoid shooting rock all over the place, I manually hammer with a hand held sledge and it crushes the rock rather easily into what I have shown in the photo of my hand. I will also be using my modified pampers (for originally laying patio brick) to also crush glass into small pieces without debris shooting everywhere. It will be much easier than my current process for breaking down glass (metal bucket and dropping a sledge hammer on it till it is mostly small pieces)

 

 

If I were in the panhandle and looking for a silica source I would research agricultural wastes and burn them.

Rotten round hay bales, manure by the ton, etc etc etc.. There are countless sources of plant materials that could yield ash.

This might be a unique additional local ingredient that you could take advantage of.

OH, in Hereford there was an old Sugar plant and they have a calcium product they market. May be worth a look.

 

If you need some contacts for such things in the area lemme know. I have people there.

Ben

[TJR]

I don't know where you guys are located. The source for silica[sio2] is flint, or quartz. If you are near a beach, those black stones are flint. They look dull black on the outside. You can calcine them in your kiln by firing them up to bisque temperature in an unglazed pot. Then they break up easily.

To break rock on a larger scale, look for a jaw crusher. Looks like to cast iron pieces coming together in a "v". Look for surplus geology equipment. A plate mill wouldn't hurt either. Used for grinding corn. Can grind rock into sand. Then it goes into the ball mill for a grind smaller than 200 mesh.

Need I go on?

TJR.

[Ben]

I don't know where you guys are located. The source for silica[sio2] is flint, or quartz. If you are near a beach, those black stones are flint. They look dull black on the outside. You can calcine them in your kiln by firing them up to bisque temperature in an unglazed pot. Then they break up easily.

To break rock on a larger scale, look for a jaw crusher. Looks like to cast iron pieces coming together in a "v". Look for surplus geology equipment. A plate mill wouldn't hurt either. Used for grinding corn. Can grind rock into sand. Then it goes into the ball mill for a grind smaller than 200 mesh.

Need I go on?

TJR.

 

 

Heat treating any rocks you wish to crush is a good test. Most will crush more easily with some application of heat.

Of course you must use proper safety gear for all of this. You don't want to breath any of this dust nor crush any important body parts.

 

TJR, please do go on.

 

 

[docweathers]

What a profile picture, AtomicAxe. I wouldn't want to meet you in a dark alley.

 

Jim

 

 

 

Now that's the funniest thing I've read all morning. What a profiile picture, OffCenter. I wouldn't want to meet you in a dark alley either!

 

 

Marcia H.

 

 

In spite of the fact that we all know these pictures bear no resemblance to their owner, they do shape our view of that person. ( yes, I am a psychologist by training)

[AtomicAxe]

Doc, my photo does bear a resemblance to myself ... since it is a self portrait. :-P

[docweathers]

I have decided to take my own advice and add an avatar that gives you the proper image of me.

[OffCenter]

I have decided to take my own advice and add an avatar that gives you the proper image of me.

 

 

Wow! That's perfect. That's exactly how I see you.

 

Jim

[docweathers]

Now you understand the pecking order around here

 

more seriously, what is the fastest you can reasonably turn a ball milling jar. I'm trying to figure out the gearing for driving my home built ball mill. it's a lot easier to turn it fast than slow.

[Guest JBaymore]

Now you understand the pecking order around here

 

more seriously, what is the fastest you can reasonably turn a ball milling jar. I'm trying to figure out the gearing for driving my home built ball mill. it's a lot easier to turn it fast than slow.

 

 

 

There is a formula based on the jar diameter.... but I don't have it here in Houston. If someone else does not post it I'll reply when I get back home.

 

best,

 

......................john