Transparent Cone 6 Stoneware Glaze
For Stonewares like M340, M325. Plainsman lab code G2916F.
This is an industrial tableware glaze recommended by tech support at Fusion Frits. It not only fires hard and crystal clear but has outstanding suspension and application properties. In addition, it works well with most stains.
The magic for the way this glaze fires and its hardness and durability lie in the variety of fluxes in contains and the very low boron content coupled with high SiO2 and Al2O3. The fluxes most likely to create micro-bubbles at this temperature are sourced in a frit. It has the traditional CaO and KNaO, but the talc adds MgO and the frit adds SrO plus a tiny bit of BaO. This mixed-oxide effect produces a very well melting glaze yet having excellent body (considering it has only 18% of a low-boron frit).
G2916F stoneware clear glaze sample board with added Mason stains. Sample are porcelain.
Button melted samples of various stains in cone 6 stoneware clear glaze.
To prepare the transparent glaze for use mix equal weights of water and powder to produce a specific gravity of 1.45 (1 kg powder produces about 1.3 liters of glaze). If you have already mixed it or are topping up a previous mix, measure the specific gravity and adjust as needed. Screen through 80 mesh (there are tiny agglomerates that will not break down without screening). Add a flocculant (like vinegar or Epsom salts) to gel the glaze until it has a viscosity such that the motion of the slurry stops in about two seconds, after stopping vigorous stirring, and then bounces back slightly (that bounce back is called the thixotropy). At this gelled consistency you should be able to evenly glaze bisque or dry ware with a 1-2 second dip, it will hang on in an even layer without dripping. This will work whether bisque has been fired to cone 06, 04 or 02 (hotter bisques will dry slower of course).
Screening: We have not ball milled this product, thus it may contain some oversize particles from the constituent materials. We advise sieving the glaze slurry to at least 80 mesh.
The recipe of this glaze is not proprietary. We developed it and sell it premixed but if you want to batch it yourself, please feel free to do so. For more detailed information at the Digitalfire Reference Library (e.g. the recipe, mixing your own, more pictures) click here. The mechanism of the recipe is explained, this may empower you to adjust it to you needs.
Adding the Stains and Opacifiers: Simply multiply the weight of the amount of powder you want to use and divide by 100. For example, if you have 2000 grams of glaze powder and want to add 6% stain: 2000*6/100=120 grams of stain. Or, 10% zircopax: 2000*10/100=200 grams of zircopax. The percentages of stain shown are suggestions. For some colors you may need to use more, others less (your fired results will demonstrate if the glaze is too dark or too light for your liking). If you are glazing a dark-burning body, consider applying a white engobe to areas where you want bright colors. For functional surfaces that you want to be white, consider applying a white engobe to the inside of the ware (at the leather hard stage) and using a transparent, this will give a much cleaner and more homogeneous surface than (white glazes do not cover well over a dark bodyies). If you are new to the use of engobes and fire cone 6, consider starting with this one.
For darker firing bodies like M390, we recommend using the GA6A base Alberta Slip glaze.
Safety Data SheetClick here for web view.
|Plainsman Clays Ltd.|
702 Wood Street, Medicine Hat, Alberta T1A 1E9
Phone: 403-527-8535 FAX:403-527-7508