2021 Shino Research Project - Part 1

This past school year, I set out on a journey to create my own carbon trap shino recipe. My goal was to create a shino that would reliably trap carbon to the point that most of the glaze appeared black, and that the surface would be glossy or at least semi-glossy. As for my parameters, they were quite simple. I would use much the same high-fire reduction schedule as I have the past few years in the gas kilns at the Polytech and I would be using the materials we have available at the Polytech. The clays I would be testing on would be Mac’s Mud Classic White and Whitestone.

I knew going into this research project that I may not come out the other end with a shino that I was fully happy with. I was fine with this prospect, as I knew that even after the course ends, I will have that much more knowledge under my belt to continue my experimentation.

As for resources going into this testing, I have John Britt’s The Complete Guide to High-Fire Glazing as a primary source of recipes, as well as glazy.org. Digitalfire.com would be another important source for information on individual materials and firing types. Additionally, I spoke with tutors and past-tutors at the Dunedin School of Art about carbon trapping, including Rob Cloughley, Neil Grant, and Michael Tannock.

In this report, I will be chronicling my research, testing, and experimentation as I go through the process.

A Note on Substitutions

Obviously, not all materials listed in recipes in books or online are available in New Zealand. Some are no longer manufactured or mined at all. Here is a table listing the materials and the substitutions I used, also the specific materials I used if a generic form was listed.

Barnard Slip — 65% Ball Clay, 35% Red Iron Oxide

Redart — Locally dug clay from Whare Flats Road

Minspar 200 — Indian Soda Feldspar

Ball Clay — Kentucky OM#4 Ball Clay

Kona F-4 Feldspar — Indian Soda Feldspar

Custer Feldspar — Indian Potash Feldspar

Phase 1

The first thing I'm doing as part of this research is to test basically as many existing carbon trap shino recipes as I can. Which at the start of this is 17. These come primarily from the ubiquitous John Britt book, The Complete Guide to High-Fire Glazes. Some of the recipes are ones found on glazy.org, and one of them is from our records here at DSA. To keep the size of this document reasonable, I have a glazy.org bookmark list with this initial recipe list of shinos which you can see here.

I made sure to use warm water to help the soda ash dissolve more fully before being sieved through 100# mesh. I got my 17 test cups labeled and poured/dipped them all on a Thursday afternoon, planning to fire them the coming Tuesday. I poured the glaze into each cup, counted 10 seconds, then poured the glaze out. Then I quickly dipped the cup upside down into the glaze. Then I dipped it half-way upside down for 10 seconds. This is the glaze mixing and application that I will use throughout this research process.

In retrospect, I didn't do the best job on this firing as I could have. It went into reduction, sure! But not heavy enough to achieve carbon trapping. I think I was a bit too antsy to get the temp up and toyed with the damper too much, causing the reduction to falter a bit. Not smart! Definitely something I will make sure to work on the next firing.

In addition to the poor firing, I think I needed to let the cups dry longer after being glazed. While four days was enough to really dry out a shino during the summer, the temperature has been dipping and doing weird stuff here in Dunedin this week. I think this meant that the soda ash didn't have the opportunity to reach the surface quite as well.

This does mean that my first set of tests didn’t contribute much to my end goal. The only one that had a little bit of carbon trapping is the one from our records, that I now call "Reading Error Shino". The recipe is titled RJ Shino, but when compared with the traditional recipe for RJ Shino, I noticed that at some point, someone had accidentally dropped the decimal in the soda ash percentage... changing it from 2.9 to 29! With such a high amount of soda ash in the recipe it's not a wonder that of all of them, that was the one to get some shadowy-ness. It's also the one that as I was taking out of the kiln I immediately dropped and smashed on the ground!

Firing chart of the first firing (Note: the controller on our large kiln is about 100 degrees off by the time it gets above 1000 degrees, so while this chart says it does not get above 1200, the cone in the firings says otherwise).

So, even though I didn't get any results I was looking for, it was still a learning process and helped with my research. I've made up a bunch more tester cups - including some Whitestone ones - for the next firing.

Phase 2

I learned a lot of lessons from the first attempt at testing my assortment of carbon trap shinos. "Surely, this next time I'll get it right!" I thought.

I did not.

The freshly fired second batch!

But I did learn a lot (again!) from this firing... and I do think that next time I'll get it (maybe? is it hubris to think that??).

So what happened? What went wrong? What went right?

A lot went right actually. Definite progress has been made. For example, I have found the perfect spot to dry my glazed cups in the studio. In the Fish Bowl (as some of us affectionately call it), where the second-year students and masters students have their desk space, it is very dry and warm compared to the rest of the studio. Besides the office, it's the smallest room we have and it uses side radiator-like panel heaters rather than the over-head heaters the bigger rooms have (which only sometimes work it seems). This means I don't have to let the cups dry for a week or more to get proper soda ash coverage. Here's a pic of one of the cups a day and a half after glazing:

Soda ash formulation on the exterior of the cup before firing.

You can see that crusty white stuff forming on the outside of the glaze. That's the soda ash coming to the surface. You can also see on the raw clay body where it's whiter - this is also where the soda ash has absorbed into the bisced clay. I had glazed this batch on a Friday morning, and taken the above photo Saturday evening. By Tuesday morning when I went to fire them, this cup was completely covered white!

So things are certainly looking up! However this is where I mess up (again). I (foolishly!) put the cups on the bottom shelf. A little background on the kiln I fire these in: this is a big gas kiln. Over the past year, Rob and I have had to do some adjustments to it to get the reduction working properly. There was a bit of time mid-to-late last year where only the very top of the kiln was going into reduction. We cleaned out the burners and had a gas guy come and adjust the pipes a bit. After that it was almost too-easy to go into very heavy reduction and a successful, well-reduced-throughout firing would take around 5-6 hours.

As more firings have gone on though, it's seeming like it's reverting to its old ways. I now have to keep the damper quite shut throughout the firing to get heavy reduction, and even then the bottom shelf is not getting hot enough nor is it reducing as heavily as the rest of the kiln. The firing for this batch took eight hours, and then it wound up not even having put the cone 10 over fully!

As you can maybe see in the above image, the cone I had on the bottom shelf (a cone 10), didn't even start going over. So these shinos are all underfired! However, they did get some reduction. I think they didn't get a heavy enough reduction at the proper temperature, combined with not getting hot enough overall, which led to yet another disappointing result.

On the bright side, some of them do show signs of carbon trapping finally! You can maybe see in the above group shot how some of them have a more greyish, almost lavender appearance. This is due to the shadowy carbon being trapped in the surface of the glaze. In addition, some of them did some much more characteristically-shino things like crawling and breaking to a bright red where thin and between the crawled bits of glaze (especially on the Whitestone cups, which I included in this test).

So what will I do next time?

·       Place the shinos higher up in the kiln

·       Fire for even longer, even if that means a 9-10 hour firing to ensure it is hot enough and reduced enough

·       Dry the shinos in the same place in the Fish Bowl

What is a technician?

Test tiles from before I was working, from testing which glazes to use in the buckets, and from trying to adjust glazes we already have but weren't working well.

(Originally posted to my old website on Aug 18, 2021)

During the first lockdown in NZ last year, we all had more time to contemplate our lot in life. For many, that contemplation specifically turned to, "Do I like my job? Is this job worth it? Should I quit and do something else?" That was certainly a set of questions on my mind and ultimately I decided to quit my job as a database manager/digital marketing person to focus on my small business. I wasn't sure if that was a good idea or not, especially going into a global recession, but I did it anyway. The more I worked in writing/marketing the more I realized it was absolutely not my jam and I just needed to go in a different direction.

Unbeknownst to me at the same time the ceramics technician at the Dunedin School of Art, Kylie, was making similar decisions. She wanted to focus on her own art and so decided to quit the technician job as we were returning to school. When I heard that the job was open, I knew this was exactly the kind of opportunity that I had to jump on! So I did, and through my experience in the department, at the OPG, and probably some luck, I got the job in June!

Now that we're in our second country-wide lockdown and I've been at the technician job for over a year, I figured it might be time to reflect back on this past year of work and learning.

So, what is a technician? What the heck do I spend my time doing?

In short, a technician keeps the studio organized and operating smoothly for the artists working in the space.

That means a whole ton of things though! I'll break it down into daily procedures, ongoing procedures, and projects.

Daily Procedures

There's a lot of things I check when I first come in each day I work. Are all the tools put away in the correct bins? Have people cleaned the wedging table? Are the buckets of glaze closed and put away under the bench? This is all just basic tidying up type stuff. For the most part, students are good about cleaning up after themselves, but some people don't. I know what it's like coming in to work on some school work only to have to spend a bunch of time before hand cleaning someone else's mess, so I try to make sure things are cleaned up. It's about keeping everything organized so other students find the tools and equipment they need when they need it.

Next, I check kilns. Do any of them need emptying? Is there a sufficient amount of greenware to put on a bisc? Should I put together a gloss firing? Biscs are the most frequent firing going on, and sometimes the most time-consuming to load, surprisingly! Although pieces can and should be touching to conserve space, handling the more delicate greenware takes a bit more consideration.

In addition to these clockwork tasks that happen all the time, as I work I help students on an individual level as necessary. I show them how to use a piece of equipment, explain glazes to them, etc. I did this kind of stuff when I was "just" a student as well because I just like helping people. It's nice to have it be part of a paid job though! Another key part of this is making sure everyone is keeping to health and safety standards for our studio. Clay dust and various glaze materials are extremely hazardous to our health, so making sure people are cleaning up after themselves properly and utilizing the necessary safety equipment is very important for everyone.

Another unseen aspect of my daily job rituals includes financial work. I make sure our department is keeping within our budget and order anything that we need. Glaze materials, clay, replacement parts for equipment, tools, and on and on. There's a lot of price comparisons and discussions between me and Rob on what we consider 'urgent' buys and what we can wait on. Some of these things can just be ordered in, but sometimes I have to go into town to buy things from hardware shops or specialty manufacturers. I've certainly learned a lot more about mechanical equipment in this job!

Ongoing Procedures

For the past year, a lot of the stuff I had "ongoing" was related to our move out of the old building and into the new building. There were bits of our old studio scattered around the art school and it was a big task getting it all back together. Even now there is still organizational work going on, like finding homes for all our hardware and tools in the workshop.

Also in this category is helping the studio stay organized and running smoothly. This means stuff like putting up signs to remind people to clean a specific area or not bring food into the glaze room. It means before the start of the year, labeling shelves so that students can start the year off knowing where their space is. I'm always assessing and talking with students about problem areas in the studio that could use some quality of life upgrades.

There's also the more typical ongoing work, like topping up materials in the glaze room, grinding and re-washing kiln shelves, fixing wheels, doing upkeep on kilns by using fire cement to apply new ceramic fiber, recycling clay through the pugmill, etc. These aren't necessarily a daily task, but something I need to keep an eye on so that things don't wind up empty or severely broken.

Projects

This is my favorite, to be honest. I get to work on new projects to help make the whole experience of working and learning in the studio better for everyone. As students in studios, I think we all think about ways we could improve the 'flow' of the studio. Now I get to act on those ideas and work with other students to improve them!

One of the first things I was tasked with was setting up an online schedule for booking our kilns. DSA has seen a huge increase in the number of in-person students over the past two years, meaning lots more people needing to fire their work. To keep things organized and streamlined I worked with Rob to set up a Google Sheets document where people can check what kilns are booked and book a firing for themselves. It's not perfect - some people continuously forget to book their kilns (and sometimes I do too!). But it's something I'm always looking for ways to improve.

My favorite project was getting to re-do all of our communal glazes we have available to our students. Our glaze buckets were a bit of a mess - lots of buckets full of glazes we no longer had recipes for, glazes that were extremely hard-panned, and of course, lots and lots of shades of brown glazes.

Glazing and testing glazes is possibly my favorite part of ceramics, so I was so excited when Rob told me this was something he wanted me to work on. I've kept some of our old glazes, but overall I've done a huge reboot. New tiles, new glazes, new bucket labeling system. It's been a ton of work and it's still not 100% finished (looking at you, raku glazes!) but it's one of the things I'm most proud of. I know the glazes are mainly intended for night class students, but I know that having interesting, usable, and well-documented glazes available is extremely useful for the diploma students as well.

Currently, I'm in a MIG welding night class at the Polytech as part of my professional development for the technician role. Knowing how to weld means I can be even more helpful in the department! I'll be able to weld parts of kilns as we build them and repair our existing kilns in ways I couldn't before.

Overall, as a technician, I wear a ton of different hats. But I have learned SO MUCH that I would not have otherwise and I really enjoy helping make the studio a more useful and fun place for the other students.