Modification Date: 2016-09-09 22:16:32
A silky zinc-fluxed matte used historically across North America
Cone 6 glazes do not melt well using traditional fluxes (e.g. feldspar, calcium carbonate), they need help. In the past it was common to employ zinc, but today almost all medium temperature glazes depend on boron (from frits or Gerstley Borate). Zinc presents a number of issues, especially with color development, but in a white matte it is a viable option.
We have tested this recipe successfully on some occasions and had issues with it on others (stoney rather than silky matte). We are testing different cooling curves and different feldspars to determine the nature of its sensitivity. The mechanism of its matteness appears to depend on the firing. At times it is a silky matte that does not cutlery mark. Others times the zinc does what zinc does: grows crystals. A mesh of surface micro-crystals. These create tiny angular protrusions that abrade metal, leaving a mark (and a surface that stains easily).
Of course, the high feldspar content means that has a higher thermal expansion. This might be OK on stonewares, but on porcelains, where it gives the best surface, it crazes.
In Bound Links
In glazes with this fault, rubbing a metal key, knife or spoon on the surface will leave black marks. In tolerable situations, the mark can be rubbed off easily with your finger. But when the problem is worse, it cannot be completely removed or washed off. This is a common fault in glazes. Even c...
A base MgO matte glaze recipe fires to a hard utilitarian surface and has very good working properties. Blend in the glossy if it is too matte.
2014-03-26 - A cone 6 boron-fluxed MgO matte developed at Plainsman Clays by Tony Hansen (a link below will take you to its page there). This page contains technic...
A glaze that is not glossy. Of course, unmelted glazes will not be glossy, but to be a true matte a glaze must be melted and still not glossy. To be a functional matte it must also resist cultery marking, clean well and not leach into food and drink. Thus it is not easy to make a good matte glaze. I...
<recipes version="1.0" encoding="UTF-8">
<recipe name="LA Matte Cone 6 Matte White" keywords="A silky zinc-fluxed matte used historically across North America" id="120" date="2016-09-09" codenum="G2000">
<recipeline material="Custer Feldspar" amount="51.700" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Silica" amount="5.600" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Calcium Carbonate" amount="18.800" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="Zinc Oxide" amount="8.600" unitabbr="kg" conversion="1.0000" added="0"/>
<recipeline material="EPK" amount="15.400" unitabbr="kg" conversion="1.0000" added="0"/>
<url url="https://digitalfire.com/4sight/recipes/la_matte_cone_6_matte_white_120.html" descrip="Recipe page at digitalfire.com"/>
By Tony Hansen