Priced Per Pound Must purchase in 25 lb increments You can find small sample sizes of this clay by clicking here. Umbria Clay #266 Cone 4-5 This gorgeous dark clay gives a reduction like dark brown color in the electric kiln. Smooth and plastic and works well for throwing and handbuilding. Because it contains very fine grog, it is also great for sgraffito projects. This clay does not like to get too hot; if you fire it at a 'hot' cone 6 or above cone 6, it has a tendency to bloat. We've had some customers comment that this claybody seems to contribute to pinholing with certain opaque glazes, which makes sense -- a clay this dark likely contains an organic fraction that has to burn out at some point, and opaque glazes just seem to be a little more prone to trapping the tiny off-gassing bubbles. However, we've found that if you fire your glazes to cone 5 with a 15 minute hold, that should take care of your pinholing. Aside from that small and specific issue, this is a lovely clay that works very well as an exposed surface. Shrinkage: 11.5% at C/4, 13% at C/6. Absorption: 2.4% at C/4, 1.4% at C/6.
