Testing black clay in reduction
Having previously got a superb result from firing Valentine's PF680 black clay in reduction I want to see how a similar approach will turn out if I use Potclay's Vulcan (medium) black clay.
Making my initial pot (left) I used a combination of decorating techniques from shellac resist, design liners, masking out areas retain unglazed areas to applying a celadon glaze.
Just as with the first pinch pot my black VUM pots have relief decorations towards the foot of the pots created by water etching. This revealed the first difference as it leaves the grog clearly visible in the recessed areas after water etching. So now I am hoping to have a similar contrast between matt and shiny areas as seen here before the shiny shellac has been burned off during bisque firing.
So, very similar to the first example I have added white, brown and black design liner details and had them bisque fired for a second time to set the design liner details before glazing.
Having applied wax resist to some areas of the decorations to keep these glaze free I have glazed them with two different celadon glazes. Neither of them are the same as the one used on the first pot (unfortunately when viewed with hindsight).
This is the result of firing these two pots in the same gas kiln as the one before at a similar temperature:
They are nothing like what I expected! Well, that is pottery for you and that is why we are doing so many test along the way in order to foresee some kind of predictable outcome. The design liners are barely visible, the glazes only show where they were really thick, the shellac texture lost its definition and all in all the pots remind me of carbonated wood.
Valentine Clays suggest a firing range form 1080°-1260°c. So, firing these to about 1280°c is obviously too hot for this clay. I do quite like the result but it is not what I am currently after. I will have to adapt my plans and do something different with my large sculpture that I've made in VUM and make another in PF680 if I want to replicate these decorating techniques on it.
