Speaking of Nuka

Speaking of Nuka. I got some great information from my friend Lance​ who is continually learning things about the beauty of the world and he creates videos to educate on his findings. He talks about “the living fossil” : Equisetum, which was around in the days of the dinosaurs. It is edible and has medicinal properties but what struck me was that it is very high in silica.

Since rice husk ash is used to create the beautiful nuka glaze. Its color is not easily describable but it has shades and hues of blue, green, white and grey. Every nuka glazed pot is different. I think that the somewhat random nature of the glaze is one of its greatest characteristics.

Look at this beautiful square bottle by Shoji Hamada Sensei using nuka over black glaze. Exquisite!

H39-B_images
Image from Pucker Gallery

 

I have a theory about my own work: that it needs to have an element of control (shaping the clay) and an element of relinquishment (letting the fire do its thing). And since my shapes are so simple, the two need a perfect balance.

Miranda Forrest published a book called Natural Glazes: Collecting and Making in which she describes the glaze using horsetail:

“The first test with horsetail ash alone produced a melted, creamy, greenish glaze with an optical blue in the centre, perhaps the most interesting single land-vegetation result to date. It also mixes well with other ashes and rock dusts. One of the other interesting effects associated with horsetail is carbon trapping during the firing, which gives a dark smoky colour to the glaze in places.”

Very very interesting! I’m all about local materials and making work that is harmonious with nature. After all, nature gives us what we need to live, to thrive and to create. Working with clay is a very primal type of creation for me.

I read somewhere that Shoji Hamada Sensia made nuka using the following

1/3 rice husk ash
1/3 wood ash
1/3 terayama stone ( a high silica bearing feldspathoid)

The highly respected Michael Coffee uses the following:

Custer Feldspar    36.00
Quartz   30.00
Whiting   22.00
OM-4   6.00
Wood Ash (unwashed)   3.00
Talc   2.00
Bone Ash   2.00

Another potter, Steve Mill uses

Silica  40
Rice Straw Ash  50
Feldspar  60

I plan to start somewhere along the lines of the simpler one and work from there. Now… Horseail grows in very wet conditions. It favors clay (how appropriate!) It’s summer. It should be around somewhere. I just have to find it 🙂 (then burn it, then wash it, then test it, etc…)

A long day getting ready

First thing to test is the kiln. If it is over firing or some other malfunction is going on its of no use to be even attempting to make a base glaze. Sarah from Olympic Kilns gave me a few cones to test with. I’ll place on each shelf so we can see if we are getting even heating from top to bottom. One thing I noticed in the last firing was that the click to turn on the elements stayed on longer than I heard it before. Almost a full 60 seconds. I don’t know if that has anything to do with it, but we’ll see.

I keep notes of glaze tests that I’ve done in the past but got a great tip from Jason and Megan at Stone Mountain Clay and Glaze – Keep a firing log and record the times that it takes to reach temperature and I suppose its good protocol to record the cooling times to room temperature as well. This will tell you if your elements are going bad or a thermocouple or something like that. Or maybe in my case if it runs very short and over-firing we’ll know by the time it is supposed to take to reach temperature. I’m trying to eliminate as many variables as possible as is standard in just about every type of troubleshooting.

Also on order and will be here shortly:

Amaco Hydrometer – for measuring and keeping a consistent glaze density

The range for dipping or pouring glazes is 0.9 to 1.00.

The range for spraying glazes is 1.5 to 1.7.

The range for brushing glazes is 2.2-2.5.

Kemper DTA Glaze Dipping Tongs – Because I’m tired of brushing on glaze and getting inconsistent applications.

Aftosa Wax Resist – For creating a more precise glaze line on the feet of my pots.

Stainless 8 Inch Caliper – I really really want to get into making lidded vessels.

Ozeri Pronto Digital Scale – Need precise measurements for each ingredient (duh!)


 

For those interested in the base glaze recipe that I intend to match to my white clay body

Recipe – Plainsman Cone 6 M370 Transparent Liner Base

Material Amount Units +/- *Stat
Nepheline Syenite 18.30 kg
Ferro Frit 3134 25.40 kg
EPK 19.60 kg
Wollastonite 6.90 kg
Silica 37.60 kg
Talc 2.30 kg
110.10

 

Witness Cones 5, 6 &7 to see where it ends up at and where in the kiln.
Respirator, because I like to breathe and want to continue to breath even after mixing dusty chemicals.

 

Christmas part 2! 5 lbs each of a bunch of chemicals.
Broken scale – new one on the way from Amazon!