|Monthly Tech-Tip |
Modified: 2023-03-14 17:10:47
A stain-based method to achieve this color using the Ravenscrag base recipe.
|Ravenscrag Slip 1000F Roast||40.00|
|Ferro Frit 3134||20.00|
|Mason 6006 Stain||10.00|
This is an excellent alternative to the GR6-E Raspberry recipe. It is simpler, just a stain addition to the standard transparent. It is more reliable. It is easy to adjust the amount of stain to get the exact shade you want. This base recipe is unusual in that it supports the development of chrome tin stains, these are available in many shades from pink to red, consider trying a different another if this color is not right for you.
Because this is transparent (contains no opacifier), different thicknesses have different intensities of color. Because it employs a stain it will be more consistent than one using chrome and tin. Add an opacifier, like titanium, to create a more pastel color with variegation (e.g. 2-4%).
No special firing curve is needed and the surface fires very clean and defect free (with a normal soak at cone 6, or even better, the C6DHSC schedule).
For mixing instructions please see the master recipe, GR6-A.
This is the Ravenscrag slip cone 6 base (GR6-A which is 80 Ravenscrag, 20 Frit 3134) with 10% Mason 6006 stain (producing our code GR6-L). Notice how the color is white where it thins on contours, this is called "breaking". Thus we say that this glaze "breaks to white". The development of this color needs the right chemistry in the host glaze and it needs depth to work (on the edges the glaze is too thin so there is no color). The breaking phenomenon has many mechanisms, this is just one. Interestingly, the GR6-A transparent base has more entrained micro-bubbles than a frit-based glaze, however these enhance the color effect in this case.
For more transparency (to make it vary more in color with changing thickness) keep the stain percentage at 10% or less.
The body on the left has 10% burnt umber adding (Plainsman M340) and fires chocolate brown (right is standard M340). The manganese (in the umber) is greatly affecting the appearance of the glaze (GR6-L).
The body is Plainsman M340 and these two glazes are based on the GR6-A recipe (Ravenscrag Slip + 20% frit). The GR6-C creamy white glaze adds 10% Zircopax to opacify it. The pink version, our code number GR6-L, adds Mason 6006 stain instead. The GR6-A base is zinc-free and just hits the 10% minimum CaO recommended to get color development with a chrome tin stain. This recipe also couples a low MgO level (MgO can kill the color in chrome tin stains).
The GR6-L (the two on the left) employs raw chrome and tin, the GR6-E uses a stain (Mason 6006). The L does not melt quite as well (because of the 10% whiting in the recipe to make sure it develops the chrome-tin color well). The GR6-E is does not need the whiting. The E is much more flexible because one can choose different stains to get different colors. Of course the intensity of the color can be adjusted by varying the percentage of colorant. And the L could be made to melt better by increasing the percentage of frit.
GR6-A - Ravenscrag Cone 6 Clear Glossy Base
This Plainsman Cone 6 Ravenscrag Slip base is just the pure material with 20% added frit to make it melt to a glossy natural clear.
GR6-E - Ravenscrag Cone 6 Raspberry Glossy
A chrome-tin burgundy glaze using the Ravenscrag cone 6 base recipe.
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|By Tony Hansen|
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