Monthly Tech-Tip | No tracking! No ads! |
This is G3948A (similar to the popular Ancient Copper product). To get this stunning result it needs to be applied thickly. Therefore it runs a lot. But the catcher glaze on the bottom cm of these mugs has stopped the flow. The catcher is a glossy black glaze and is hardly noticeable. I use G3914A as the catcher but Amaco Obsidian would also likely work. The inside glaze, G2926B, is one I have tested and developed to fit our clay bodies really well.
These porcelain mugs are sold at many tourist shops on the Alaskan cruize circuit. Made in China of course. But their quality is astounding. And they teach multiple lessons to potters - great skill in the use of decals (even inside), meeting different glazes at the rims, evenness of application, layering, the use of wax resist, etc. They likely have a glossy and matte base glaze and add stains (to get the black, blue, red, white, green). Notice they have an iron red (lower right) that is stable enough not to run and host an even more fluid melt second layer. They also have a stoney yet functional matte white (bottom left). You can make dipping glaze versions of all of these:
Black glossy: G3914A and G2926BL
Black matte: G2934BL
Iron Red: G3948A
White stoney matte: G2934Y2
Glossy colors: Add stains to G2926B
Matte colors: Add stains to G2934
Yes. Ancient Copper, as of Nov 2023, it is no longer available. Right is G3948A, our iron red (a publicly available recipe). Both of these have been fired using the C6DHSC slow cool firing schedule. As you can see the PC-56 crystallizes more, matting the surface in the process. But if cooled normally (e.g. using the PLC6DS schedule) it does fire similar to G3948A. Likewise, G3948A can be made to crystallize more if the iron oxide percentage is increased in the recipe (we use black iron, it is a little less concentrated than red but does not gel the slurry). The recipe offers excellent slurry properties when mixed as a dipping glaze. Our version uses Spodumene (which has 7% Li2O). Of course, lithium materials are very expensive these days, but that is what is needed for this effect. If you make a brushing glaze of it using our instructions only about 70g of spodumene is needed to make a 500ml jar. At current material costs, we could make 3 jars for $10 worth of powdered materials!
Glossary |
Catch Glaze
A catch glaze of the lower section of a piece of ceramic or pottery is often needed to arrest the flow of reactive runny glazes (so they do not run down on to the kiln shelf). |
---|
Buy me a coffee and we can talk