It seems the black underglaze ran???
Process:
I inscribe words with a sgraffitto tool on the pottery in the leather hard stage. Then bisque fire it. Then, paint on underglaze- black underglaze from amaco.
Then I wipe off the excess with a sponge.
Then I glaze the piece.
Oh, and the glaze is a cone 6 celadon glaze.
Here's what I remember doing different with this kiln load:
I wiped the excess underglaze off the pottery on the same day as I glazed the pieces, meaning that the bowls weren't totally dry when I glazed the pieces.
At the end of the glaze firing I let the kiln cool to room temp instead of unloading it at 150 degrees or so as I sometimes do. Didn't even prop open the kiln at 500 or so degrees as it was cooling. Slower cooling...
I left the black underglaze on the bowls for a couple hours or so before wiping the excess underglaze from the pots.
Instead of using brand new underglaze, I used recycled underglaze- the same black underglaze that which was used before and had been taken off the bowls with a sponge but was at the right consistency because the water had evaporated already.
I am bummed because I have a sale tomorrow and well--- I think I'll sell these as seconds. Oh well! Lots of learning in this pottery world, isn't there?
Looking forward to your wisdom- thanks for reading!
5 comments:
I don't think the slow cooling has anything to do with the black underglaze being smeared or not filled in enough. I think the recycled underglaze may be the problem; it may be too diluted.
Also applying the glaze before the pot was dry because you have two different materials working against one another. the green glaze looks a bit splotchy is that the effect you are bummed about?
Sorry about the kiln load mishap, clay seems to know when we want it behave and it behaves like a fickle beast complicating our lives at just the wrong time.
What Linda said sounds right. If you are using water and not letting the pot dry, your glaze will be thinner.
Also, is this a different clay body?
thanks to you both! great to hear from you. I agree--- that I think it's
1. that I used the recycled underglaze---which is a bit diluted and still had some water in the crevices maybe when I put the glaze on it, so it needed somewhere to go?
And,
2. the black underglaze maybe had not completely dried... (didn't think this would matter!)
the green wasn't the problem- that's from multiple dips and I don't mind that--- and part of it is from the bad pic.
more bummed from the black underglaze spreading....
starrwhite cone 6 clay.
same kind of clay body I've been using...
well, this was bound to happen. at least I'm in good company when I read of similar things on other's blogs! :(
I think some testing is in the future for me!
Don't know why recycled underglaze would be a problem unless it got contaminated with another material.
My guess is that if the underglaze was not completely dry when the glaze was applied it may have blended slightly with the glaze.
Second guess is based on the fact that I experience differences in temp in my kiln. Sometimes designs can blur a little it they are in the hotter part.
melissa- hi! thanks- I think your first guess is the solution. Am planning on doing some test glazes about this to help solve it. Interestingly, at the sale today people weren't bothered and while I sold the pottery at a discount, they loved it. one remarked about the mystery of it....us potters can be so particular at times.
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