For about the past year, Steve Chou has been mentoring me on the best ways to get my pottery online and into the world. Steve and his wife have an interesting story, they run a successful online store selling unique wedding linnens online. He now operates a website that helps entrepreneurs start an online business. He asked me to share my experiences with his course in a guest blog posting. Enjoy!
Follow this link to view my handmade ceramic pottery and to see the store that Steve helped me build. Also, be sure to check out my Facebook page where I share info and photos of my pottery processes and influences.
The Nuka glaze originated in Japan centuries ago. Potters traditionally made the glaze by using ashes from burnt rice hulls. These ashes were high in Silica, which is a glass former, so some Nuka glazes could be made with almost entirely ash.
Phil Rogers describes the Nuka glaze in his book “Ash Glazes” along with a huge variety of other glazes. I learned many of my glazing techniques from this book, like creating custom glazes from raw materials which is how I develop all of my glazes.
Check out the awesome Nuka glazed bottle below, made by Japanese folk potter Shoji Hamada. He was renowned for making skillfully crafted pottery inspired by his natural surroundings, and made with natural materials that he harvested locally. This Nuka was made with 50/50 ash and stone, and a black Tenmoku was brushed over.
Press-Moulded Bottle, Shoji Hamada, 1963, from “Ash Glazes” by Phil Rogers, pg. 19
Ash as a Glaze Ingredient
Every other year, I pick up about 200 gallons of wood ash from my friend who heats his family’s home with wood furnace. He harvests most wood from deadfall trees in the St. John’s Arboretum. I like using this ash because it’s a natural material that I can get from a local waste source. It’s also free, but takes a lot processing to get rid of all the charcoal and debris. The image below shows some tools I made to sift the ashes through 12, and then 40 mesh screens.
Developing Glaze Recipes
I’ve spent about three years developing recipes for my Nuka glaze. Technically, it many not be a ‘Nuka’ anymore due to all the materials I’ve added. I still call it a Nuka because I’m inspired by the materials and surfaces used historically, but my glaze has become pretty complex.
Traditionally, Nuka glazes were fired hotter than most glazes. While I was still in school at CSB/SJU, my professor Sam Johnson and I got great results with the Nuka when firing upwards of cone 12, or over 2500 degrees F. Since graduation, I’ve lowered the temperature to cone 10, or just under 2400 degrees F. I did this by using line blend testing. I could write another blog post on line blend glaze testing, so for now I’ll just refer you back to Phil Rogers, “Ash Glazes.”
For all you potter readers, here’s my Glossy Nuka glaze recipe for cone 10. If you dry-sift ashes through a window screen you could probably get similar results. I keep this glaze at about 145 specific gravity to keep it from dripping off the pots:
Glossy Nuka
Parts
Percentage
Wood Ash – dry sifted
33
18.5
Custer Feldspar
50
28.1
Silica (325 mesh Flint)
30
16.9
Frit 3134
15
8.4
Whiting (High Purity)
20
11.2
Bone Ash
10
5.6
Bentonite
10
5.6
Talc
10
5.6
total
178
100.0
Brushing Iron and Cobalt
I accent each pot with iron or cobalt washes on the rim. These naturally drip down each pot during the firing, creating a surface that reminds me of wet paint. I like to think of each pot as a canvas for glaze. The cup on the left was also electric fired at cone 10, while the mug on the right was gas fired. I think that the extreme oxidation of the electric kiln contributes to the crystal growth in the cup, which is highlighted by the iron as yellow specks.
The cups above were gas fired at cone 13, back in 2011. This is one of my favorite versions of the Nuka because of the glossy, milky surface and the color complexity of the iron drips. I’ve spent years adapting my new recipes to reproduce this surface, and I’ve discovered a huge variety of colors and textures within the Nuka color pallet. The lower cone 10 temperature has been a good challenge for this glaze, and I hope to develop a cone 6 Nuka in the near future.
I’m also exploring more ways the Nuka relates to my other 2 glaze choices: Copper Red and Tenmoku:
*Added November, 2016:
To view the most recent evolution of my Nuka Glazed “Standard Ware” pots, including “Nuka Cobalt” and “Nuka Iron” color pallets, view our online store: store.cherricopottery.com/standard-ware
Here’s the list of events Wednesday – Saturday of next week where you can check out my pottery around St. Cloud, MN. I’ll be performing throwing demonstrations and showing my newest pots, so stop by and hopefully you’ll find the perfect Christmas gift:
– Wednesday December 5th, from 10am – 6pm
@ the Atwood Memorial Center, St. Cloud State Campus, St. Cloud, MN
– Thursday, December 6th from 10am – 6pm
@ the Gorecki Fireside Lounge, College of St. Benedict, St. Joseph, MN
– Friday, December 7th from 10am – 5pm
@ Bodiddley’s Pub and Deli in St. Cloud, MN
– Saturday, December 8th from 10am – 1pm
@ Sartell Winter Farmers Market, Sartell City Hall, Sartell, MN
Check out the posters for these events below. Hope to see ya there! If you can’t make these shows be sure to check out my online store: store.cherricopottery.com
My most recent gas firing produced some amazing color variations. The kiln was filled top to bottom with pots only glazed in my Copper Red glaze. About half of the pottery had great red colors, ¼ had great red but with color variation, and the remaining ¼ were mostly green, pink or gray. The natural gas flame paints the glaze surface, and potters are blind to this process.
Thanks to my intern Samantha Thury for shooting these images. I many never know exactly how to produce the reddest of reds, but here are some of my guesses:
Bright red/red-orange: consistent reduction and temperature throughout the firing, slower flame path, less oxygen entering the kiln.
Burgundy: heavier reduction. Often gradates to violet, black and then clear. Seen in areas of the kiln where uneven reduction causes flame to become trapped, and then simultaneously over-reduce and oxidize different areas of the same pot.
Gray-Pink: somewhat of a mystery…consistently seen on the left side of this kiln, and in certain other areas of the kiln. The flame could be slower, causing more reduction. Perhaps there is heavier reduction during a certain point in the firing. This color is often seen next to bright red, but rarely seen next to clear. This could mean that reduction is achieved before cone 5, but perhaps too much reduction is achieved.
Gray: transition color mostly seen from bright red/burgundy to clear, but seen here on a more red/pink to clear transition.
Clear: oxidized. The bottom shelf of most kilns usually results in clear, sometimes with hints of red or violet. Achieving medium reduction before cone 5 and through cone 10 could eliminate clear. I also see clear closest to the burner ports and target bricks, where the flame path is faster and more turbulent.
For all you potters interested in producing your own Copper Red glazes, check my previous blog post for my glaze recipes and firing techniques:
Back when I first made pottery for the Local Blend in 2010, I couldn’t make enough to replace their plastic water cups. I wasn’t worried, because I thought the majority of customers would use mugs and dinnerware. They serve food, soup, pastries and a huge variety of coffee drinks, so I wasn’t worried about a few plastic cups here and there. Boy was I wrong…
Plastic water cups made up almost half of the serving vessels used by customers. The images below show how these cups were really an eyesore; they totally distracted from the pottery.
During the spring of 2011, I made a goal of getting all of the plastic vessels out of the Local Blend. The idea was tough because the restaurant broke too many water cups years ago when they used glass, so they switched to plastic. I had to come up with stable, durable forms.
I also had to fit at least 20 cups within a 14” x 14” space, which was no problem for the stackable plastic cups. I quickly decided my pottery simply wouldn’t stack well, so I designed a custom shelf to fit this space. The shelf was about 13” x 13” which allowed for 4 cups to fit in each row, as long as they were no wider than 3” at the rim or foot. With 3 tiers, it can easily hold 24 cups.
I used a Japanese “dragonfly” measuring tool to ensure that each cup was roughly the same size. This tool is crucial when making mugs for a restaurant, because each mug must shrink to the correct 12oz, 16oz, or 20oz. size. Otherwise that medium iced frappe latte mocha just won’t taste right.
Stop in the Local Blend sometime and you can eat and drink from my artwork! For more info check out the “Pottery at the Local Blend” section of my website.
