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Silk screening is a popular decorating method. There is no better way to get a quality screen than having an aluminum-framed one made at a shop that specializes in this process (e.g. t-shirt printers). You can buy those hinges from a supplier online. This screen is 16x20 inches and I have multiple designs on it - I made them in Adobe Illustrator, which enables a vector graphic original that gives superior quality. I am about to screen lettering and a logo onto a tile. Although companies like Speedball, Amaco and Mayco make inks for this purpose, I am using an ink I made by mixing a black stain into a ceramic medium and adding enough water to achieve a viscous gel.
Black brushwork needs to go on thick enough in one brushstroke. Commercial products we have don't do that - thus my motivation to work on this. Another issue is that they try to cover too wide a firing range (thus they melt too much at the high end and not enough at the low end). I am experimenting on cone 6 Polar Ice porcelain jiggered bowls using G2926B dipping glaze. The base underglaze recipe here is a 90:10 MNP:nepheline syenite mix (you could use your own porcelain instead of MNP and feldspar instead of nepheline). To that, I add 15% black stain, 1.5% CMC gum and 5% bentonite. With the CMC gum and bentonite, and blender mixing, a brushable consistency that stays put can be achieved at a fairly low water content compared to commercial products (enabling it to go on thicker in a single brush stroke). Assuming application at leather hard state, the drying and firing shrinkage can be matched to the body by varying the plasticity of the porcelain used (e.g. the percentage of bentonite it contains). And the percentage of stain can be tuned for enough color but no bleeding, bubble clouding or crystallization. And we can adjust the degree of maturity by varying the proportions of MNP and Nepheline (commercial underglazes often melt too much by cone 6 and fade and diffuse as a result), this one stays opaque black.
Underglazes suitable for making silk screen transfers are another special case. The ideal one needs to cover well like this one. But it also needs to gel and harden enough to hang onto the paper but not so hard that it does not separate and transfer to the ware. Commercial products for brushing are unlikely to be optimal so it makes sense to mix your own and experiment with different amounts of gum.
Glossary |
Silk screen printing
Silk screen printing is one of the best options for hobbyists and potters to reproduce crisp and detailed decoration. But there are many details to know. |
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