An interesting view of my most recent round of test glazes. Each Oil Spot variation was dipped in porcelain and red stoneware with the red stoneware tiles shown. The firing was: 10 hr oxidation to Cone 7, 2hr oxidation slow climb to Cone 8, 3 hr slow climb to cone 10, 1 hour oxidation hold @ cone 10. The results were pretty cool, and under magnification they had just the right amount of galactic goodness. The pictures were taken with a USB digital microscope! Magnification is about 30-40x
For the longest time I’ve wanted to try firing oil spot glazes, and after a bit of research it was pretty satisfying to make it happen. I decided to begin by concentrating on black, single glaze variations – the recipes of which came from a number of sources, mainly John Britt’s ebook and Complete Guide to High Fire glazes, a few from Michael Bailey’s Oriental Glazes, and a couple from Hopper’s The Ceramic Spectrum. The next step is to start zeroing in on some of the more spectacular variations and then start changing up the recipes and the firing schedules for maximum effect. Enjoy!
Dolomite 5 Whiting 5 F4 Feldspar 65 Epk 5 Silica 20 Cobalt Carb 5 Red Iron 24 H20 65
Dolomite 5 Whiting 5 Custer 65 EPK 5 Silica 20 Cobalt 5 Red Iron 8
Dolomite 3.6 Whiting 3.7 F4 48 EPK 9.6 Silica 35 Cobalt 5 Red Iron 8
Dolomite 4.7 Whiting 4.7 F4 61 EPK 5.4 Silica 24.1 Cobalt Carb 5 Red Iron 8
Taken in 2007 during my studies in Jingdezhen, China. This thrower uses the traditional gaolin china clay. I drew a picture of a large round vase with a small neck and then he proceeded to make exactly what I drew while also making the clay do some truly remarkable things!
So I wanted to see what all of my locally available commercial clay looked like in our Soda Kiln. I took 12 commercially available clay bodies tested in this base recipe to get an idea which were more likely to flash:
10 Nepheline Syenite, 10 200m Silica, 80 Clay
For good measure I threw in a few Shino glazes, and tried calcined EPK for the hell of it (I actually wanted to see if it deflocculated like the rest of them.. it didn’t really…)
From the 100g test batches, I then tested each slip/shino on Laguna 550 Porcelain, B-Mix, and Miller 510 Stoneware in 2 firings that were unfortunately pretty similar in atmosphere and soda introduction. First firing on top, 2nd on bottom. Tiles were scattered throughout the kiln, so some got blasted, others not so much. Standard body reduction and reduction firing to cone 9/10, heavy reduction during soda intro, and reduction cooling from 2300-1800F. I scanned the sides that were more interesting, or showed more variation. Hope this helps you narrow down what you might be looking for with soda fired clay slips!