|Monthly Tech-Tip |
This black engobe, L3954B, is on a cone 6 buff stoneware (at leather hard stage). Because a thin layer works well with this high-opacity engobe it is possible for the slurry to be more fluid, less gelled. An immediate benefit of this is that it dries more quickly (enabling handling of the piece within a few hours). Another benefit is a much more even coverage than would be possible with more a viscous consistency. The thinner layer also means much fewer issues with flaking during drying. However application of the engobe takes patience, waiting for drips to stop and gelling to set in and hold it in place.
This is the L3954B engobe. 15% Mason 6600 black body stain has been added (instead of the normal 10% Zircopax for white). Of course, a cover glaze is needed, but even without it is absolutely coal black (so a lesser stain % is possible). Lots of information is available for L3954B (including mixing and adjustment instructions). Engobes are tricky to use, follow the links below to learn more. L3954B is designed to work on regular Plainsman M340 (this piece), M390 and Coffee Clay, these bodies dry better than porcelains and are much less expensive, coating them with an engobe to get a surface like this makes a lot of sense. This engobe is actually a highly plastic body, but it does not contain enough feldspar to be a porcelain (this is on purpose to match the firing shrinkage of the stonewares). This can be adjusted to fit any stoneware.
Engobes are high-clay slurries that are applied to leather hard or dry ceramics and fire opaque. They are used for functional or decorative purposes.