| Description |
This material is not typical of any other glaze material currently out there. Its claim-to-fame is mainly two fold:
-It is possible to use it 100% to create a silky to glossy glaze at cone 10 because it contains all the feldspar, silica and clay needed and these are supplied in majority from the natural clay.
-It imparts beautiful working properties to the glaze slurry: it suspends it and improves evenness of application, drying speed, reduces shrinkage and enables multi-layering (many of the most beautiful art glaze effects can be achieved by layering one glaze over another).
You can visit www.ravenscrag.com to learn more. The site shows a lot of very interesting glaze formulation work and recipes and comments are recorded on the site. In addition to some of the nice multi-layer effects, you will find one glaze in particular, a blue cone 6, to be quite stunning (it is a worthy successor to floating blue because it lacks its persnickety nature). If you want to dabble in developing your own glazes, Ravenscrag Slip is a great place to start.
One exciting thing that has emerged is that Ravenscrag is at home in high, medium and low fire glazes. At high temperature it can be used as-is with additions of color, opacifier, etc to create glossy and matte glazes. At middle temperature, 20-30% frit seems to work well. At low temperature 50-60% is needed. Frit 3195 at low fire produces a very attractive silky matte surface having a nature that is much more lively than the typical toilet-bowl type low fire glaze we are used to. Ravenscrag also has potential as a tile glaze since it applies well on dry ware.
Plainsman Clays made a change in the Ravenscrag recipe starting with mix number 4288 from May 2002. It now has 10% added calcium carbonate to make it melt better. If you have a material with a code number whose first four digits are lower than this, add 10% whiting to get the same results as on the web site. |