Cone 6 Ravenscrag Slip Glazes

Ravenscrag has excellent application properties and it is easy to layer various glaze recipes (some of the best results have been achieved by this method).

Care should be taken not to fire them too fast or at too low of a temperature. Witness cones are recommended to assure you have reached cone 6. These glazes have worked in our studio at Plainsman Clays but we recommend testing them in your circumstances and on your clay bodies for fit.

Test for leaching by placing your glaze sample in vinegar over night (or for a few days) to see if the color or surface has changed at all (if it leaches it may not be food safe depending on what materials are in the recipe). Also test for crazing by heating glaze samples to around 350F and then submerging them into room temperature water (do this 2 to 3 times).

Ravenscrag Recipe A: Clear Glossy Plainsman Cone 6 Ravenscrag Slip Glaze
Ravenscrag clear on M340	Recipe Ravenscrag Slip 80.00 Frit 3134 20.00 100.00	Notes -This recipe is a clear even glossy glaze with a smooth surface. Passes the hot/cold crazing test on M340. Suggested additions: - 5% titanium , 1% cobalt, 1% copper and 0.5% iron oxide for a light glossy blue glaze with some lighter variegations, breaks to a green over the edges. -3% Cobalt Carb., 3% Rutile, 3% Titanium for a variegated light medium blue glaze that breaks greenish over edges. -2% copper and 2.5% titanium (survives vinegar test without leaching). Produces a celadon green with some crystal growth on the bottom of the bowls where it pools if thick or if cooled slowly. -12% zircopax for a white Majolica type glaze -12% iron oxide red, 1.5% cobalt for a dark black with a tinge of blue. - 2% Chrome Oxide, 2% Cobalt oxide for a dark teal.

Ravenscrag Recipe B: Variegated Light Glossy Blue Plainsman Cone 6 Ravenscrag Slip Glaze
Ravenscrag light blue on M340 Small porcelain vase	Recipe Ravenscrag Slip 80.00 Frit 3134 20.00 Cobalt Oxide 3.00 Rutile Ceramic 3.00 Titanium Dioxide 3.00 109.00	Notes This produces a variegated light medium blue glaze that breaks greenish over edges. This glaze is very consistent and has very good working properties. Variations 5% titanium, 1% cobalt, 1% copper and 0.5% iron oxide: A light glossy blue glaze with some lighter variegations, breaks to a green over the edges. 3% Cobalt Carb, 3% Rutile, 3% Titanium: A variegated light medium blue glaze that breaks greenish over edges. 2% copper and 2.5% titanium: Does not leach on vinegar test. Produces a celadon green with some crystals growing on the bottom of the bowl where it pools. Normal application

Ravenscrag Recipe C: White Glossy Plainsman Cone 6 Ravenscrag Slip Glaze
Ravenscrag white on M340	Recipe Ravenscrag Slip 80.00 Frit 3134 20.00 Zircopax 12.00 112.00	Notes A white base glaze with all the advantages of Ravenscrag Slip based glazes (not highly fritted, you can do multi-layering, it is not drab look like a porcelain sink or toilet).

Ravenscrag Recipe D: Black Glossy Plainsman Cone 6 Ravenscrag Slip Glaze
Ravenscrag Black on M340	Recipe Ravenscrag Slip 80.00 Frit 3134 20.00 Iron Oxide Red 13.00 Cobalt Oxide 0.50 Chrome Oxide 0.50 114.00	Notes Every potter wants a good reliable glossy black glaze that has a minimum of toxic metals and fires to an even color without pinholes and blisters. Ravenscrag slip has the unusual ability to host a black color from a high iron content (only a tiny amount of cobalt and chrome are needed).

Ravenscrag Recipe E: Raspberry Glossy Plainsman Cone 6 Ravenscrag Slip Glaze
Cone 6 Ravenscrag Raspberry Ravenscrag Raspberry on M340	Recipe Ravenscrag Slip 70.00 Frit 3134 20.00 Whiting 10.00 Tin Oxide 7.50 Chrome Oxide 0.50 108.00	Notes This type of glaze is very difficult to achieve at cone 6 since the chrome and tin require high calcium, zero zinc and low boron. Bases that work fine with other colors will often produce grey with chrome-tin pink or maroon stains or oxide combinations. Glazes that do work in this system are normally highly fritted so the chemistry is sympathetic to the color development, however such glazes are often difficult to work with. This base is the opposite, it has beautiful working properties, you can do multiple layers and it has all the other benefits imparted by a high Ravenscrag Slip content. Medium to medium thick application is best. Breaks clear around edges to highlight irregularities in the surface.

Ravenscrag Recipe F: Slip High Alumina Matte Plainsman Cone 6 Ravenscrag Slip Glaze
Ravenscrag glaze on M340	Recipe Ravenscrag Slip 60.00 Frit 3134 20.00 Dolomite 10.00 Calcined Alumina 10.00 Cobalt Oxide 2.00 Rutile Ceramic 5.00 107.00	Notes This is a high alumina matte glaze and is a favorite. It is not temperature sensitive and produces good results at cone 5, 6 and 7 (medium blue surface breaking an olive type green where thin). Most base glazes do not host alumina well and fire with pitting and uneven surface (alumina is very difficult to melt and dissolve). Be sure to use a smallest particle sized alumina you can find (it is avaible in very fine grades, much finer that the average ceramic material).

Ravenscrag Recipe G: High Calcium Matte Blue Plainsman Cone 6 Ravenscrag Slip Glaze
Ravenscrag high calcium blue on M340	Recipe Ravenscrag Slip 55.00 Whiting 10.00 Dolomite 15.00 Frit 3134 10.00 Silica 10.00 Cobalt Carbonate 2.00 Rutile Ceramic 5.00 107.00	Notes This glaze is temperature sensitive. It requires a slow cool down to allow crystals to grow. If the kiln cools too quickly you will get a glossy glaze. Has a nice soft smooth surface, with a varigated light blue color. This base will also work well with other coloring oxides/stains. It is temperature sensitive and should be fired to cone 6.

Ravenscrag Recipe H: Oatmeal Matte Plainsman Cone 6 Ravenscrag Slip Glaze
Ravenscrag oatmeal on M340	Recipe Ravenscrag Slip 60.00 Calcined Alumina 10.00 Dolomite 10.00 Frit 3134 20.00 Manganese Dioxide 4.00 Rutile Ceramic 5.00 Illmenite Granular 0.30 109.30	Notes Good oatmeal glazes can be difficult to achieve at cone 6 oxidation. Application should be thin to medium.

Ravenscrag Recipe I: Floating Blue Plainsman Cone 6 Ravenscrag Slip Glaze
Ravenscrag floating blue on M340	Recipe Ravenscrag Slip 70.00 Magnesium Carbonate 2.00 Dolomite 13.00 Frit 3134 15.00 Rutile Ceramic 5.00 Cobalt Oxide 2.00 Copper Oxide Black 1.00 108.00	Notes David Shaners cone 6 floating blue has been used for many years by thousands of potters. However it contains gerstley borate which is no longer available (see GerstleyBorate.com for information in this classic recipe and the material). In addition it is a tempermental recipe and is prone to blistering. This version is much more reliable and has all the other benefits afforded by a high Ravenscrag content. Application should be thin to medium and a fast cool down is required to prevent crystallization. It can be fired to cone 5 or 6.

Ravenscrag Recipe J: Dark Green Crystal Plainsman Cone 6 Ravenscrag Slip Glaze
On M340 at cone 6	Recipe Ravenscrag Slip 70.00 Dolomite 15.00 Frit 3134 15.00 Copper Oxide Black 2.00 Cobalt Carbonate 0.50 Rutile Ceramic 5.00 107.50	Notes This recipe turns out a glossy clear that ran slightly. This sample is on Plainsman M340 clay.

Ravenscrag Recipe K: Glossy Light Blue Plainsman Cone 6 Ravenscrag Slip Glaze
By itself on the left, over another glaze on the right.	Recipe Ravenscrag Slip 68.00 Zinc Oxide 10.00 Custer Feldspar 20.00 Lithium Carbonate 2.00 Titanium Dioxide 3.00 Rutile Ceramic 5.00 108.00	Notes This glaze is quite fluid, it can produce nice effects when used over other glazes. Has a nice surface, and good application properties. Water in glaze slurry turns a coca cola brown when it has been sitting for a while. Would need to be screened occasionally since Lithium crystals form. Variation: 2.5% titanium, 2% copper (instead of Titanium an Rutile) for a light lime green glaze, with some crystals where glaze is thicker, has a beautiful surface to touch.

Ravenscrag Recipe L: Magnesium Matte Glaze Plainsman Cone 6 Ravenscrag Slip Glaze
Cone 5 on porcelain Cone 6 on porcelain Cone 7 on porcelain	Recipe Ravenscrag Slip 60.00 Cornwall Stone 20.00 Dolomite 20.00 Cobalt Carbonate 2.00 Rutile Ceramic 5.00 107.00	Notes This recipe sources magnesia from dolomite to create a silky matte surface. It is temperature sensitive and needs to be fired to cone 6 to develop the best matte surface. Note that high magnesium glazes can tend to cutlery mark. This cobalt, rutile variation produces a light mossy green/blue color breaking light blue over edges (at cone 6). The samples shown are made with Plainsman M370.