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Copper Sand

 

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Remains of Maria Copper Mine, near Millford, UT

 

I talk a lot about the process of exploring and discovering in my work. Indeed, my MFA Thesis Show was all about giving a full context of how I go about adventuring, prospecting, developing, and ultimately making pots from the stuff I find.

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I love the idea of being an alchemist – and I describe myself as someone who uses mineralogy, chemistry, and fire to forge beautiful objects and glazes. But I have to admit that more than anything, discovering the really compelling stuff is mostly a matter of luck, circumstance, and time. It’s very labor intensive, and I’d guess that for every 10 rocks I bring into the studio, it’s usually only one or two that have any real practical value in my work. I suppose that given enough time and enough firings, one could utilize just about anything under the sun… but in the real world there’s just never enough time – or test tiles!

Materials
Collected and Melted Materials from near Red Lodge, MT

 

In this post I thought I’d share the background of the material that I’m calling Copper Sand. It can be summed up in a single sentence: “I was adventuring in the Utah Desert and found some mysterious green dirt which I collected and put in a 5 gallon bucket, then after not immediately being able to use it as a glaze, I tried, tried, tried, and tried some more to find a way to use it.” The longer version of the story starts the summer earlier. In looking around the internet and researching Kaolin materials, I surfed around and found mentions of mining activity near Eureka, Utah, for a somewhat exotic Kaolin-like mineral called Halloysite. Halloysite is a mineral of great interest to material scientists, as it’s chemically identical to Kaolinite,(Al2Si2O5(OH)4) but rather than having a plate like molecular structure, it’s shaped like tiny tubes and needles.

For many years Halloysite was used primarily in industry as a cracking catalyst in petroleum refining. Nowadays it’s being researched in a whole range of commercial and scientific applications. Of course after reading about it being mined in Utah, I wanted to get my hands on some. After a few emails went unanswered, I did what I recommend to anyone in this kind of thing – I just showed up! I met the right person at the right time and eventually got access to some very cool places and some very, very cool materials.

 

The next summer, I planned a week-long digging and fishing excursion throughout west Utah. I thought I’d begin my trip from Eureka, and after calling my friend, it was decided that we’d meet up and head down to Topaz Mountain. We both wanted to go check out some old Flourite mines in the Thomas Mountain Range.

 

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Flourite and Bertrandite

 

On our trip, we were accompanied by a geologist who was an old hand in Nevada gold fields, a rockhound, and a hell of an interesting guy. I mentioned to him that I had plans to drive around rockhounding and asked if he knew where I could find some copper. He started rattling off a bunch of places and told me that in the 80’s, his mineralogy field trip went to The Old Maria Copper Mine and they found all kinds of flashy malachite and chacopyrite among the piles of old copper ore tailings. It was a few hours south, and seemed like an interesting place to go poke around. I pulled out some maps, he pointed to the vague area, and told me to go drive and look around. And that’s exactly what I ended up doing.

Here’s a video from one of my camps near the Wah-Wah Mountains in Utah.

 

 

Outside of Millford, where the geologist had pointed out the old mine – I was surprised to find a very large and very active copper mine. After driving around and staying outside of fences and no trespassing signs, I drove up to the security gate. I mentioned that I was a geology student from USU, was interested in the mining activity area, and wondered if the foreman or anyone had any time to show me around or give me any info. The answer was a definitive “No.”

 

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Current CS Copper Mine: Photo Credit Ken Lund

 

After a few more questions, I pointed to some old buildings and tailings piles and asked if I could poke around. To my surprise, I was told, “Yea. You can help yourself to any of that stuff. Just stay out of the buildings, don’t touch the generator, and don’t do anything stupid.”

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Remains of the Maria Mine – Summer, 2016

 

I spent a day slowly working through the piles of boulders (tailings), finding a whole range of malachite, azurite, chrysocolla, arsenopyrite, chalcopyrite, calcite, and quartz samples.

 

 

I wouldn’t say that I found any truly world class samples, but there was interesting shit everywhere! It didn’t take long to run into the classic rock hound conundrum – finding way more than the vehicle weight limit.

Throughout the piles, I kept finding bright yellowish green rocks that were soft and weathered. Geologists describe these rocks as ‘friable’ and they crumble readily. Having had, now, enough experience hammering boulders into gravel with a sledge hammer, I tend to seek out friable materials and places where mother nature or mining activity have already given me a head start on the milling process.

With my jeep packed to the gills, I grabbed a 5 gallon bucket and filled it with the weathered, disintegrated green sand from a particularly bright green rock. I was thinking at the time that it might just make for an interesting glaze (honestly, I think this about every material I collect!). I had no idea what it was exactly, but it had me curious, and that’s really the only thing one needs.

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Back in the studio, I went through my usual process of melting, experimenting, and researching. Fusion tests suggested a material with a lot more copper than I expected. Analysis showed peaks of Magnesium, Iron, Copper, Titanium, Zinc, Silver, Lead, Calcium, Sodium. There’s a lot going on with the composition and chemistry of this bucket of material, and if I were to crush it all and blend it, I might end up with a mixture that’s something like:

  • Calcium Carb 40%
  • Copper Carbonate 20%
  • Silica 10%
  • Alumina 10%
  • Magnesium 10%
  • Iron 10%

 

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X-Ray Diffraction of the melted material suggested Augite and Chalcopyrite.

 

 

With the initial melt tests and info I’d gathered, it became obvious that it wasn’t going to be as simple as ball milling it and then dipping pots into whatever came out. One of my last glaze firings in Utah was a soda kiln with about a dozen porcelaineous stoneware cups with this green copper material wedged right into the clay body. I used a few glazes on hand; a celadon, an oribe, and green salt. They all came out looking like pure hot trash! Crusty, pitted, pinholed, metallic charcoal black – not the surfaces I was interested in at all. I needed a new glaze and a new approach. Unfortunately, it had to wait for the dust to settle from my graduation, and move from Logan, Utah, to Red Lodge Clay Center in Montana.

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A cup from the 2nd series

 

For the past few months I’ve worked on the aesthetic and technical issues of incorporating course rock materials into porcelain clay and high temperature glazes. It’s taken about 7 series of cups to find a process that works for me. In the first series everything was too dark, too much copper, incompatible glazes, pinholing, cracking, etc. In the second series I sieved and measured the material before wedging it in, and tried new glazes – results were better, but pinholing and foodsafety was still an issue. The 3rd and 4th series were about more refinements in sieving, measuring, incorporating and and wedging, but this time I lined the greenware cups with porcelain slip thinly, then thickly. I also tried a few new glazes, had a better firing and payed closer attention to glaze application. The results were better, but the interiors were still pinholing and cracking.

 

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Cup from 3rd series

 

With the fifth series, I didn’t wedge in the material, but made a viscous, partially deflocculated slip with a handful of copper sand blended in. I dipped the cups into the slip, leaving the interior as bare porcelain clay. Results were better, again, but getting the slip mixed and applied right was tricky business.

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Cups from 4th and 5th Series

 

With the 6th series, I tried mixing the material into a shallow bowl of deflocculated slip and using a brush to apply the rock/slip mixture. I also improved my glazes, settling on a white, blue celadon, and oribe glaze. Results were better yet.

 

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A cup from the 6th Series

 

In the 7th, and most recent series, I made and bisque fired the bare porcelain cups. I then brushed on a mixture of rocks and glaze using a hake hair brush and a series of shallow bowls that I could mix in varying amounts and grain size of rock.

 

So that’s about where I’m at now. I’ve got a lot of things dialed in with this last round of pots, and in the next few series I’m going to to be exploring heavy reduction, heavy carbon trap soda firing with these reduced copper red colors. I’m also planning to sneak in an oxidized oribe firing for some bright vivid blues and greens.

 

Stay tuned on Instagram @bluepotter for regular updates!

 

 

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Copper Sand cups from multiple firings and re-firings.

 

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SEM Images of Ceramic Glazes

      These are a collection of high magnification images of the Oilspot droplets and interesting surface features that are forming on the surfaces of my ceramic glazes. I took all of these images at Utah State University, in the Core Microscopy Facility using a Quanta II Scanning Electron Microscope.
       I came to USU because I wanted to go really deep into the technical aspects of material science and glaze chemistry. I didn’t anticipate getting down to the nanoscale, though. This year I was given a scholarship to do just that – to get trained and learn how to operate a Scanning Electron Microscope so that I could research my materials and glazes with some of the most powerful microscope technology that exists. The learning curve was incredibly steep, and the deadline for my show didn’t allow for a more in-depth and rigorous suite of chemical and elemental analysis. But with that said, they did give me the keys and put me in the driver seat to do whatever I wanted.
        Being an Artist, I approached the machine from a very different point of view. I was interested in finding compositions and interesting structures – and then imaging at the highest possible resolution settings. I knew I wanted to print these things BIG, and the 24×36″ images I printed for my show took approximately 30 minutes each to scan – which was a very long time for an image. The scientist in charge of the machine thought I was crazy, and wasting my time – but when they were scaled up and printed, it proved to be worth the effort! I was very happy with how they all turned out.

Fiske Hare’s Fur Oilspot Glaze – Stoneware, Cone 11 Oxidation

 Fiske Lava Oilspot Glaze – Porcelain, Cone 12 Oxidation

 

Manganese Saturate Glazes – Porcelain, Cone 10 Oxidation

Thesis Exhibition: Pyrosynthesis Writing

Artist Bio/Statement

Bio

Matt was born in Carbondale, Illinois and grew up in Southern Indiana. In 1999 he was introduced to ceramics in high school. Matt earned his BFA in Ceramics and Art History from Indiana University in 2007. During this time he spent significant time living and traveling in China, studying the history and technology of Chinese porcelain. After graduating from IU, he spent several years living in Seoul, South Korea. Before coming to Graduate school at USU, Matt was a ceramics artist in residence at the Armory Art Center in West Palm Beach, Florida. He was the first recipient of the USU X-STEM fellowship, and his research involves material science, geology, and ceramics.

Exploring Cook Canyon, UT

Exploring Cook Canyon, UT

Artist Statement

Daily life plays an important role in what I make and why. The needs of the kitchen and home are for me, like many potters, a useful starting point for conceiving specific utilitarian forms. I make a lot of cups, bottles, and drinking vessels. Lately I’ve been interested in the idea of designing and making these vessels in sets. For me, there’s nothing better than gathering with a group of friends, eating, drinking, and using handmade ceramics. I’m motivated to make objects that enhance these experiences and enliven domestic spaces.

My work explores the intersection of ceramics, material science, and geology. In my mind’s eye, glaciers give way to icy celadon glazes, volcanoes ooze magma as molten glazes cascade down curves and roll off edges, crystals grow and forms take shape when conditions are right. I’m an avid rock hound, and for the past three years I’ve explored the mountains and landscapes of Utah, Idaho, and Montana.  There are many gemstones that have analogues in ceramics – and much of my research has been centered on studying and understanding the underlying science of materials and firing processes. For me there is something incredible and romantic about the idea of transforming rocks and dirt into beautiful things.

In the end I strive to integrate my desire to make utilitarian pottery with a love of materials and nature. What drew me in and keeps me interested on a daily basis are the endless variations possible in ceramics. The idea of constantly searching for new possibilities is at the heart of who I am and why I do what I do. At the same time, I love the constant challenge of pairing forms and surfaces, sourcing from the history of ceramics as I source materials from my local surroundings. I think my strongest work finds a balance between all of these ideas, and my hope is that my work evokes a similar curiosity in the people who see and use it.

Exhibition Statement

         Pyrosynthesis: n. synthesis or creation initiated by or resulting from the action of heat.

I like to joke that I’m equal parts artist, pyromaniac, rock hound, and nerd. Add to that an interest in history and technology, along with a penchant for experiments and testing, and it describes who I am and what I do quite neatly. As a graduate student in ceramics at Utah State I’m in the perfect place to satisfy all of these interests. For the past three years I have specialized in the transformation of common raw materials into ceramics through the action of heat and fire – hence the title. There are a lot of parallels between what I endeavor to do, and what the alchemists of ancient history sought to do, namely to turn lead into gold. In my case, I’m interested in the transformation of locally abundant rocks and dirt into objects of beauty and interest.

 

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This exhibition, then, is a culmination and presentation of my work on this subject. To explain it simply, all of the work in this gallery has at least one component of a prospected (dug up or picked up off the ground and drug back to my studio) material utilized in the finished piece. The best example is the granite bottle and cup set on the granite slab. In this piece, the glaze is made entirely out of the finely ground up granite rock dust. Coarser granite rock particles were incorporated into the clay body, thus providing black speckles on the unglazed clay surface. The base, too, is a broken granite boulder that has been cut and polished flat to provide a stone surface for the ceramic objects to live on. My hope with these combinations is to draw a direct connection between the ceramic object and the materials they come from. For me, the novelty of melting rocks in a ceramic kiln never gets old – each experiment generates still more new questions than answers, and Utah has been an amazing place to find all kinds of interesting materials. I’ve included 9 of the most interesting materials that have captured my interest.

Starting just to the right of this statement, I’ve included several piecess to help give context to my process and research and shed light on how the finished pieces come about. I should mention, too, that I took all of the 2 dimensional images with the Scanning Electron Microscope here on campus. I often study my experiments and tests for a long time before they end up on finished pots, and the SEM has given me the ability to analyze and learn about the materials and firing process in a way that I still can’t believe. Not only are these images a wealth of information and data, but from an artistic standpoint, I see them as dramatic landscapes and images of incredible beauty. Finally, the pots themselves are at the heart of everything. Over the course of my graduate studies at Utah State my sense of design and craftsmanship has been challenged like never before, the result of which is a body of work that is hands down the best I’ve ever made. Thanks for coming in and having a look around.

Local Materials

Local Materials/Making a Glaze Piece

Local Materials/Making a Glaze Piece

 

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From Top to Bottom, Left to Right.

  1. Manganese Saturated Kaolinite/Halloysite from near Eureka, Utah.

Manganese is a very interesting element, and provides some wonderfully interesting surfaces. In certain conditions it can yield dramatic rainbow iridescence. Small additions account for the optical phenomena in the iridescent Hare’s Fur Glazes as well as the Manganese Saturate Glazes.

  1. Quartzite from Willard Canyon, Near Brigham City, Utah.

This is a rather interesting flavor of Quartz, having trace amounts of Chromium, which accounts for the lovely green color. It provides a very high concentration of Silicon Dioxide (glass) in glazes. It was used in the dark green Basalt Celadon glazes.

  1. Dolomitic Limestone with Calcite from Dry Canyon, Logan, Utah

The first material I began experimenting with at Utah State, this material is used in glazes as a glaze flux – which is to say, it’s a material that lowers the melting temperature and promotes flowing, dripping glazes. It’s used in all of the black Oilspot and Hare’s Fur glazes.

  1. Travertine from Porcupine Reservoir, Utah.

I picked this stuff up not knowing what it was, but fascinated by the texture. I later learned what it was and that it formed in chaotic hydrothermal conditions, you could think about this material as nature’s very own hard water deposit. Similar to the Dolomite, it acts as a flux in glazes. It was used in conjunction with the Dolomite and Quartize on the bluish grey teapot.

  1. Black Schist from Willard Canyon, near Brigham City, Utah.

Essentially a metamorphosed clay or shale, this flavor of slate contains some really beautiful pyrite (fools gold) inclusions. By itself it is refractory and unappealing, but with a 10% addition to a celadon base glaze, it provides a beautiful sky blue. You can see the blue and the pyrite inclusions on the blue bottle set.

  1. Topaz bearing Rhyolite, from Topaz Mountain, Utah.

This stuff is just amazing. High in Silica and Alumina, it also speckled with Topaz gemstones (mostly very small in scale – this sample is exceptional). It’s features in all of my Basalt/Rhyolite glazes, which I’ve named Fiske Lava Oilspot. The recipe? 3 Parts Rhyolite, 1 Part Basalt. See the small test tiles for what it looks like fired by itself.

  1. Granite from Cook Canyon, Near Willard, Utah

Plain old granite. It turns out this stuff makes a beautiful range of glazes completely by itself. Its used as a glaze on the 2 Tiered Granite Slab piece, and it’s used in the matte black glaze on the set of 4 cups on the smaller granite base. The matte black comes from an addition of 1 part Hematie (Iron Ore) to 4 parts Granite.

  1. Vesicular Basalt (Lava Rock) from Sid Butte, Idaho.

The local geology abounds with basalt of all flavors, but compositionally, they’re all relatively similar – at least as far as my glazes and firing process is concerned. This specific variety got me started on researching basalt glazes, and when I started using the lava oilspot glazes I incorporated local Utah varieties from outflows near Delta, Utah, as well as roadcuts off in Box Elder County, Utah. It accounts for the rich reds and oranges in my Lava Oilspot Glazes.

  1. Iridescent Hematite from near Eureka, Utah

This spectacular sample survived my hammer and the studio milling equipment. It’s nearly pure iron. Less spectacular examples have been incorporated into all of the Iridescent Hare’s Fur Glazes and Black Oilspot Glazes, as well as the Black Granite Cup Set.

Making a Glaze

A glaze is nothing more than a glass-like coating fused to a ceramic surface by heat.

Nearly any rock or mineral can be utilized in a glaze. Most ceramics studies are stocked with materials that have been mined and commercially prepared for consistency and ease of use. But you can easily dig up anything and see what happens, sometimes it’s not at all useful for ceramics, but sometimes it is – and these are wholly unique to the place you get them from.

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  1. The first thing I do when I bring back a sample (1a,1b) to my studio is to use my trusty sledge hammer to break a small sample into pea-sized gravel. This gravel then goes straight into a small bowl (1c), and straight into a kiln. After this initial firing to 1250C (2350F – that’s HOT!), I can usually get a very good idea of what a sample might do in glazes. I might not have any idea what a material is – but after firing it, you can tell how it will behave at standard ceramic temperatures. Sometimes one gets lucky (as was the case with the granite) and ends up with a material that makes a perfectly acceptable ceramic glaze all by itself. Usually though, it takes some testing to find out how to fire specific materials.
  1. Because the atmosphere in the kiln has an effect on the color of the glazes it’s useful to do initial melt tests in an oxidized (regular atmosphere) firing (2a) as well as firing the material in a reduction (excess fuel, reduced oxygen atmosphere) (2b) The firing atmosphere changes the color of the clay and the material quite significantly. My Oilspot glazes rely on regular atmosphere firing conditions for the phenomena of oilspots to occur. Celadon glazes, on the other hand, require reduced oxygen conditions for the iron to change from it’s oxidized (rust!) red color, to a reduced black color. These tiny black iron molecules are what make my celadon glazes appear blue.
  1. (3) is a sample of granite melted at 1250C. Right away I could tell this was going to be a great material to work with. With no additions it’s good to apply directly to pots as soon as it’s milled. The liquid in (6b) is pure granite glaze.
  1. (4) is a sample of Black Schist melted at 1250C. You can see that this sample needs to be amended or mixed with another material to make a useful ceramic glaze.
  1. It can be useful to fire samples at lower temperatures to find out when exactly they start to melt and fuse to a clay surface. (5) is a sample of basalt fired to about 1000C, which was hot enough to affect the iron in the basalt, but not enough to melt the bulk of the other minerals present.
  1. After establishing that a rock is going to be useful, it’s time to begin preparing it for use as a glaze. A 15 pound (bowling ball sized) hunk of rock will provide about 5 gallons of glaze. 5 Gallon buckets are a standard in most studios, and I used about 5 gallons worth of glaze to finish all of the black and Hare’s Fur Oilspot pieces in this exhibition. Making a rock a glaze material is a rather simple process of using a hammer or milling machine to crush rocks into fine powder. My favorite way to do this is to use a ball-mill, which is essentially a heavy-duty rock tumbler. To a tightly sealed metal jar you add: 3 Parts material, 3 parts water, 4 parts porcelain balls(6a). Put this jar on a machine that spins, and in about 24 hours it does the job that takes Mother Nature millions of years (who is constantly turning mountains into clay). The mill works by mechanically mixing and breaking the material into finer and finer pieces. Your done when the material (6b) passes through a fine mesh strainer. You can then dry it out and use it like any other ceramic raw material (6c) or you can dip or apply it directly onto pottery or test tiles (7).

Basalt, Iridescence, and the Firing Process

Iridescence, Basalt, and the Firing Process

Left: Iridescence, Basalt, and the Firing Process, Right: Lava Oilspot Glaze

In the course of poking around and looking at rocks in Idaho, one particular sample of basalt caught my attention. The iridescent vesicular basalt on the right an example of what I picked up. I became very interested in the question of why this material had a bluish iridescent metallic sheen – and why the rocks next to it didn’t. I speculated that since some ceramic glazes can be fired in ways to make them turn iridescent (raku firing, for example) it might just be the case that I could fire basalt in a way that it would turn out with the same lustrous metallic surface.

I then set about testing my theory. I started by making nine 8” stoneware tiles, which would all have the same application of the same ground basalt. I then designed a series of firing schedules where I would change two variables: 1.) Atmospheric Conditions Inside The Kiln – specifically whether I would keep the kiln in oxidized natural atmosphere or whether I would reduce the available oxygen by firing in a gas rich environment. 2.) Cooling Speed. Of particular importance in the color of ceramic surfaces is the speed at which a molten, melted glaze cools down and crystallizes when the burners are shut off and the kiln returns to room temperature. In this series of firings, I took careful notes, paying very close attention to both the atmosphere in the kiln and the rate at which I allowed the kiln to drop in temperature.

I did indeed find that I could reproduce a metallic iridescent blue sheen from basalt lava rock (see the tile in the middle). The trick was to fire the kiln normally, and then cool the kiln very rapidly to about 1000C (which is the stage in which the viscous, molten material starts to harden) and then hold the kiln at a steady temperature in a reduced oxygen environment for an hour or two, then begin a very slow -2 degree per minute drop in the same reduced oxygen environment until the glaze had completely solidified around 700C.

Iridescence, Basalt, and the Firing Process

What I learned through this series of experiments is that the iron in basalt and other iron rich glazes is greatly influenced by rate of cooling and atmosphere. By manipulating the atmosphere and rate of cooling, I could affect the colors of glazes – thereby producing unexpected surfaces and colors. It was this research that then led me to develop all of the variations found in both of the installation pieces in this show. The glazes are the same- but the firing processes are very different.

Rhyolite/Basalt Glaze (Lava Oilspot Glaze)

Lava Oilspot Glaze

Lava Oilspot Glaze

While it was exciting to work with basalt as a material, in most cases it left something to be desired as a functional, utilitarian ceramic surface. It had the tendency to run completely off the pots, and it often had a blistered, matte surface. Very few glazes in ceramics contain one singular material, sometimes a glaze recipe can call for as many as 20 different materials. I needed to add something to my basalt to make it more functional, and a breakthrough came after my Mineralogy class fieldtrip to Topaz Mountain, in Southwest Utah where I collected a 5 gallon bucket of Rhyolite gravel.

Rhyolite, which is another volcanic rock and it lies on the on the other end of the spectrum of igneous rocks. Rather than being high in Iron and Magnesium like Basalt, Rhyolite is very high in Silica and Alumina. In glaze chemistry, you can think about Alumina as the opposite of a flux. Rather than lowering the melting temperature, it raises it. Referring back to the local materials in this show, you might notice that I’m using Dolomite and Travertine to increase the melting and moving of glazes in the kiln. Conversely, I’m using Rhyolite to stiffen and slow down the melting of the glazes.

Often the first experiment to do with a prepared local material is to do what’s called a line blend. The five pieces on the shelf below are what are called test tiles, because it’s often not feasible to devote a piece of pottery to a glaze you don’t know much about. In a line blend, you move in steps from one material to another. The tiles below represent a progression from 100% Basalt , to 75:25, to 50:50, to 25:75, then to 100% Rhyolite. In other words, on one end of the line you have one material, in the middle you have a perfect mix of the two, and on the other end of the line you have the other material. You can move in big steps, which takes less time, or you can move incrementally. The point then, for a line blend is to help you narrow in on a nice proportion, and sometimes a second series will help you narrow it down further – say the 50:50 and the 75:25 test tiles look very promising, you might then decide to do a second progression from 50:50, 55:45, 60:40, 65:35, 70:30, and then 75:25. The possibilities are endless, and you can add in a third and fourth material to the blends and very quickly use up a lot of test tiles and explore a lot of variations. I’ve also included some of my notes, which cover only a few of the thousands and thousands of glaze tests I’ve mixed and fired.

Slide4

I was lucky though and the first line blend yielded my Lava Oilspot Glaze. It’s 1 part Basalt, 3 parts Rhyolite. A very simple glaze recipe for sure. But remembering also that the firing and cooling have a great deal of influence on the finished surface, I’ve spent the last year investigating the possible variables on this very simple recipe with very, very complicated firing and cooling processes. The results of which are the 16 Rhyolite/Basalt Bowls, all of which were made from the 1:3 recipe, but fired in very different kiln cycles. I’ve also included some examples of several of my firing cycles.

16 Lava Oilspot Bowls

16 Lava Oilspot Bowls

The Scanning Electron Microscope

Scanning Electron Microscope

Scanning Electron Microscope

My research with the SEM on campus began with a generous scholarship from the Office of Research and Graduate Studies. With my membership to the Microscopy Core Facility, I was able to take my own samples and prepare them for analysis on a state of the art Quanta Scanning Electron Microscope. Fen-Ann Shen, who oversees the SEM was a patient teacher, and she taught me first how to use the equipment on calibration samples, and then later, to prepare my own ceramics and begin looking at the surfaces and structures on the nano-scale.

Manganese Saturate Glazed Vases, SEM Image of Mn. Glaze

Manganese Saturate Glazed Vases, SEM Image of Mn. Glaze

It should be said that an SEM is not an optical microscope – and by that I mean it’s not what you’d normally imagine a microscope to be, namely, a tabletop instrument with two lenses that you look in. While optical microscopes are useful for looking at surfaces, magnification maxes out at about 800-1000 magnification. An SEM, on the other hand, operates on the principal of firing a concentrated beam of electrons at a sample and analyzing the electrons as they bounce back (backscattered). Scanning is in the name because this beam moves across the surface of the sample, building an image as the resulting information is compiled. While an optical microscope maxes out at around 1000x, the SEM at USU is capable of 300,000x magnification. In effect, you can look at nano-particles in high resolution. That’s 1/1,000,000,000 of a meter! A human hair is about 100,000 nano-meters in diameter. It’s therefore quite easy to get completely lost in an area smaller than an eighth of an inch.

SEM Sample Mounts

SEM Sample Mounts

The images in this exhibition represent some of the most exciting surface features and topographies from my own glaze. To date I’ve only looked at 3 glazes, and all of them are in this exhibition. I’ve included the actual samples themselves, which are mostly broken shards and chips of glaze. As I began to learn more about the equipment and preparation, I began to make samples specifically to fit on the small conductive sample mounts.

I might also add that these images represent the very beginning (I’ve spent less than 20 hours looking at my glazes) of what I see as a very exciting chapter in my exploration of materials and glazes. Most published images are the result of hundreds, if not thousands of hours spent in front of the monitor, patiently waiting for scans to complete. I was lucky, then, to capture the images I did, and I’m very excited to continue this research in the future.

Acknowledgements

            A special thanks to The Office of Research and Graduate Studies along with The Caine College of the Arts for providing me with an incredible ART-STEM fellowship – without this funding, it wouldn’t have been possible for me to devote all of my time and energy to focus on my research. My fellowship has opened doors to departments across campus, and has facilitated a great amount of collaboration and research outside of the Department of Art and Design.

Thanks to the USU Ceramics Faculty for giving me a long leash to play around and melt things and make messes – and thanks also for reigning me in when I got carried away and always reminding me that I can’t fire kilns without actual work. Without craftsmanship there is no concept.

Thanks to my Graduate Advisory Committee for helping me decide what I should be doing, not what I could be doing. Thanks also to John Shervais and the Geology Department for help with my projects and insight into material science.

Thanks to Kenzi Lowry for help with the graphic design of my postcards and posters and helping me format the SEM images and get them ready for printing. Thanks for working under impossible deadlines and tolerating my constant adjustments and second guesses and indecisiveness.

Thanks to Fen-Ann Shen for training me on the use of the Scanning Electron Microscope and helping me figure out how to prepare and analyze my ceramic samples. I look forward to investigating more materials in the Microscopy Core Facility.

Thanks to Nicholas Gialanella for providing me access to the printers in Photography and working with me to produce the SEM images.

Thanks to Ryoichi Suzuki, who had a huge influence on my thinking about the possibilities of stone and for giving me access to the sculpture facilities.

Thanks to Miles Howell for his help in preparing and roughing out the stone bases – he got done in hours what would have taken me days!

Thanks to all of my graduate and undergraduate colleagues in Ceramics, for putting up with my messes and firings, and for inspiration and camraderie. Also, a shout out to the corner for the tough love.

A final thanks to The Department of Art and Design. Laura, Becky, Tori, and Janet, you’ve all been incredibly helpful and supportive not just in the run up to this show, but throughout my time at USU. Thank you!

 

 

Basalt as Colorant in Celadon Glazes

Basalt as Colorant in 2 Base Recipes.

Basalt as Colorant in 2 Base Recipes.

More local Basalt. Here used as colorant in high fire celadon glazes. On the top left, the raw material which was collected from various places throughout Idaho and Utah (and all mixed together), bottom left the homogenous, calcined, milled, sieved, and dried material ready for glaze.

In this set the basalt is supplying the iron necessary for that timeless celadon blue. Its also bringing significant additions of magnesium and calcium to the recipe. The % of basalt here ranges from 0 to 10% in 2.5% steps – applied to a dark stoneware and porcelain tiles.

This series were fired in a very fast and simple cone 10 reduction firing with a very basic reduction cool. 6 hours start to finish, in a small fiber test kiln — Heavy body redux for 30 min @ ^012-^08, then light redux to ^6, then a medium redux to ^10. At soft cone 11 I crash cooled a few hundred degrees, turned the air and gas down, dampered in, and put the kiln into about a -4°/minute cool, periodically opening the door to quickly crash cool -30 or -50 degrees until 1400, then shutting everything off. In some cases reduction cooling will effect the color and quality of the glazes significantly, but here it only effected the stoneware – keeping the iron oxide on the surface in its black reduced form. A good reduction firing will yield these glaze colors with no special effort cooling – here the RC was strictly for a darker stoneware color.

The Recipes

Fiske’s Tichane Chun
Custer Feldspar 48
Silica 31
Calcium Carb. 20
Bone Ash 1
(Iron Oxide 1.5)
— A range .5 to 3% Iron Oxide gives a similar spectrum of blue as the basalt does here – different flavors of Iron bearing materials yield different flavors of glaze, obviously. I’ve tried probably more than 50 kinds of iron over the years – try what you have and figure out what flavor you like best!

Fiske's Tichane Chun with 1.5% Red Iron Oxide. Fired to C10 in Reduction.

Fiske’s Tichane Chun with 1.5% Red Iron Oxide. Fired to C10 in Reduction.

Fiske’s (Pinnell Clear) PC Celadon
Custer Feldspar 25
Grolleg Kaolin 20
Calcium Carb. 20
Silica 35
(Spanish Iron Oxide .85)

Fiske's PC Celadon with a range of 0%-2.55 Red Iron Oxide. Fired in C10 Reduction.

Fiske’s PC Celadon with a range of 0%-2.55 Red Iron Oxide. Fired in C10 Reduction.

 

Liquor Bottle Set

Rhyolite and Basalt Glazes

I was beyond excited to work with my newest found material, a rhyolite from Topaz Mountain, in Juab Country, Utah.  This time rather than choosing a handful of very large rock samples (to insure relative material consistency), I instead went to a wash and filled up a 5 gallon bucket with very fine material the size of course sand. My reasoning this time was that consistency is completely relative, and as long as I get materials from the same spots, it doesn’t matter – and I can grab material that has already been 99% processed for me. In the end I think this worked out, because I was able to run 5 gallons of sand through our ball mill with 2x 1 gal. ball mill jars in 10 batches. But I’m getting a bit ahead of myself, because I think it’s important to test fire a material before you go through the trouble of ball milling. So my new first step in dealing with materials (after identification of course) is to take a small chunk, put it in a small dish, and fire to cone 10 in reduction. Since this is my primary temperature range, that’s it, if there are chances I’ll also put similar samples into cone 6 oxidation as well as an oilspot firing schedule, which is about cone 12 oxidation. Here was the result at cone 10, in reduction:

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A small rhyolite pebble after being fired to cone 10, in reduction.

 

Looks a lot like a fired chunk of granite or feldspar. Onwards with the milling!

Someone asked me about my process for ball milling, and here it is: Fill a 1 gal ball mill jar 1/3 with mixed sized media (approx 50% 1/4″ balls, 25% 1/2″ balls, 25% 1″ balls) then fill the jar with 1/2 gallon of water, then fill the the rest of the container up with material until it’s about 2/3 full.) If I had more containers I wouldn’t exceed filling the jar 1/2 way, but my circumstances are what they are, and I haven’t needed to change anything yet, such as it is.

In reduction, this rhyolite material was surprisingly similar to my ice crackle glaze. I think with very little modification (a small addition of clay, bone ash, and maybe a bit of frit) I’m nearly positive this will look and feel like a Kuan, ice crackle glaze.

Rhyolite Glaze on a high Iron clay body. Fired to cone 10 in Reduction.

Rhyolite Glaze on a high Iron clay body. Fired to cone 10 in Reduction.

Once I had all of my material milled, I let it sit overnight and then drained off the excess water, leaving me with a glaze slurry with an SPG of 1.58 (That’s 79g of material in a 50cc syringe). That’s only important if you want to know how much material you have per given volume. Since I was going to blend this with a basalt material that was also in solution, I needed this info. After taking the SPG of my basalt material, which happened to be 1.54, I did a simple line blend. On both sides are the materials by themselves, in the middle a 50/50, and on the left and right middle 25/75.

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Rhyolite/Basalt line blend. Red stoneware (top row) and porcelaineous (bottom). Fired to cone 12, oxidation.

 

Pretty interesting results, I think. The big surprise was how sweet the 25% Basalt and 75% Rhyolite mix came out.

1 part Basalt, 3 parts Rhyolite. Fired to cone 12 oxidation.

1 part Basalt, 3 parts Rhyolite. Fired to cone 12 oxidation.

Finally, because I was looking for an oilspot/tenmoku type glaze with this research, I should also detail my firing schedule. Here’s my current Blaauw gas kiln firing schedule:

0 time_temp 00:00 5
1 time_temp 01:30 200
2 time_temp 07:00 1160
3 time_temp 01:30 1200
4 time_temp 01:00 1220
5 time_temp 02:00 1230
6 time_temp 01:15 1252
7 oxidation 80
8 time_temp 00:08 1252
9 oxidation 150
10 time_temp 00:30 1220
11 time_temp 01:30 1200
12 cooling
13 time_temp 02:00 1000
14 time_temp 02:00 800
15 time_temp 02:00 700
16 time_temp 02:00 500
17 time_temp 02:00 300
18 time_temp 02:00 50
19 time_temp 04:00 50

Blaauw kilns have the capability of firing in extremely oxidized conditions – blowing in somewhere to the tune of double the amount of air needed for complete combustion. The default, and maximum air value is 200. An neutral flame is around 100, and a smoky reduction is something like a 70.

Basically, this program fires up to cone 6 in about 9 hours, and then goes slowly up to 1252C, reduces for 8 minutes, and then goes back to oxidation, drops to 1220 over the course of 30 minutes, then drops to 1200 over the course of an hour and a half.  I’m still very much tweaking this schedule, which works very well for some glazes, and not so much for others.

Rhyolite From Topaz Mountain, UT

View From Topaz Mountain, Juab County, Utah. Photo by Phil Konstantin

View From Topaz Mountain, Juab County, Utah. Photo by Phil Konstantin

A few weeks ago the USU Mineralogy class took an overnight field trip to Topaz Mountain in Juab County, Utah. This location is known for an abundance of semi-precious gemstone, namely a champagne colored topaz, opal, and red beryl. Unfortunately, the topaz loses its color after exposure to UV radiation (sunlight) so the gemstones, although beautiful, aren’t super valuable.

Of more interest to me, of course, was the rhyolite material itself. After working quite a bit with the ultramafic (high in magnesium and iron) basalts from the Snake River Plain in Idaho, I was coming to the conclusion that I needed to add in silica and alumina to stabilize this glaze and keep it from flowing off of my pots as well as having a nice and glossy glaze surface. Quite by luck, I was in the perfect spot to find a material that was precisely what I needed to mix together with my basalt material to get something interesting.

In the end, I had a lot of fun busting open rocks and attacking the rhyolite outcrops with a 5 pound sledge. I took some pictures of some of the coolest, and largest topaz pockets, which are referred to as “vugs”. At the end of the day I filled up a 5 gallon bucket with this material and brought it back to the studio to go straight into the ball mill. More on the results in a later post!

 

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A vug I unearthed filled with Amber Topaz.

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More vugs filled with the distinct champagne colored Topaz. Unfortunately these topaz lose color with exposure to sunlight.

 

From the paper 'Geochemical evolution of topaz rhyolites from the Thomas Range and Spor Mountain, Utah. - Christiansen, Bikun, Sheridan, Burt, 1984

From the paper ‘Geochemical evolution of topaz rhyolites from the Thomas Range and Spor Mountain, Utah. – Christiansen, Bikun, Sheridan, Burt, 1984