Friday, 17 August 2012

Testing, testing.

Just a quick post to show some of what came out of yesterday's firing. I fired a few test pieces with the fen slip as a glaze and took them to cone nine. The result was a rather horrible dull, blacky brown, but in oxidation I wasn't really expecting much from it. More exciting was this white ash glaze I mixed up last week..I placed this over a normal off-white stoneware (left) and over a 50/50 mix of the fen clay and raku.

Sample on left has black and iron underglaze decoration

Above sample on right, close up

The glaze on the right has turned a kind of granite-like pink-grey and the black underglaze a dark bluey green..quite remarkable! There are also yellow-brown spots coming through from the clay body...I like this finish very much.

Here are a few of the pots:

Carved sake cup with ash glaze

Carved sake cup (no glaze but soaked in soda ash solution) with fen slip inside

Sake cup (no glaze) with fen slip inside

Sake cup detail

Sake cup. Ash glaze over iron decoration

Oribe cup, or yunomi
Oribe cup, or yunomi

I was getting tired of finding the odd burst bubble in the oribe glaze, so I added a tablespoon of frit to the mix, hoping to make it less viscous. It does seem to have helped with bubble and crater formation, but perhaps it also made this last yunomi's glaze crawl. It was on the top shelf whereas the non-crawled glaze was on the bottom where it may well be cooler. Also the carving pattern on the crawled pot is less vertical, so the glaze may have pooled more. (Actually, I think it's crawled in a way which adds interest, rather than making it really ugly as crawling sometimes does) So I'm not sure whether adding frit was a great idea or not..I think I need to find a new oribe glaze.


  1. Hello Mark--I left a comment, but I think I did something wrong? So I will try again. I so love the ash glaze! When I was a lab tech and helped in running the kilns, we did cone 10 reduction. The oribe glaze we used would cause some problems--mainly pin-holing. We bisque-fired to 04 so we knew that wasn't the problem. We sprayed on a thin rutile/colemanite (Gerstley or Frit) wash which helped. It's an old trick and an extra step. Which was hard to get students (always in a hurry, naturally) to spray just one little pot after the dip in the glaze bucket. Oh, but when they did and saw the resulting pooling green and was love.

    1. Hi Charlene, only your last comment was received, so something must have gone awry..perhaps the security code wasn't accepted? That has happened to me a few times.

      Thanks for telling me about your experience with oribe, I've never heard of applying washes in that way..maybe it's something I'll try in the future, but I don't have proper spraying equipment at the moment. I find my cone 9/10 oribe glaze rather's hard to know where the problem lies when one firing is perfect and the next less so. Not significant faults, but I would prefer a flawless finish. I think I would like to find a more reliable, lower firing oribe, perhaps cone 7.

  2. The right test looks like stone with a petroglyph drawing on it very intersting. The black sake cup is wonderful.

    1. Thank you, Linda, I'm not sure if I'll be able to repeat this petroglyph effect..I've got a feeling it will depend alot on glaze thickness.