september pots

kiln-open.jpg

this morning I had a glaze firing to unpack. it was a weird firing. the kiln gained heat when I closed the gap on the flue for reduction, and lost heat when I opened it up. the opposite of what it normally does. I discovered a large amount of flame leaking out of the side of the flue, here, just under the top. I can fill this space up with ceramic blanket after I have pushed the side of the flue back out to where it should be, it’s leaning in about half an inch at the top. that’s the red stained section in the middle.

shed-003.jpg

anyway, the firing was fine, up to temperature, with just about perfect reduction. I was very worried as there seemed to be very little reduction between 1000 and 1100 degrees, no soot to speak of, and no back pressure. but there was plenty of green copper staining on the barium glaze over porcelain, and the barium went quite dark gold where it was double dipped as on the centre band of this big bottle.

06-reverse-chalk-beach-bottle-with-scored-porcelain-overlay-54cm-x-24cm.jpg

although I was a little at a loss as to what to do with this pale grey clay body, it’s fine with the porcelain overlay, and works perfectly well with the crawling shino glaze. the copper/tin/dolomite glaze gave some quite garish oranges on top of it, but that’s quite fun for a change.

05-saltmarsh-tubular-vessel-with-scored-porcelain-overlay-39cm-x-12cm.jpg

the first pieces I made with it were the two rectangular dishes, and this is the more exciting of the two. it was tucked quite close under a shelf and I set some cones at each end. the greenish-blackish end got cone 11 (porcelain temperature, 20 degrees higher than stoneware)  lying down flat and cone 12 starting to bend, but it doesn’t seem to have affected it at all. the porcelain overlay is quite thick, so it cracked in the biscuit firing; a nice crackled effect.

02-saltmarsh-dish-with-scored-porcelain-overlay-39cm-x-35cm.jpg

I put the last of the terracotta crank pieces in this firing, somewhat circumspectly in a cool-ish corner,with the barium glaze on it. it certainly had no problems with the temperature it got, which probably was not cone 11, more like 10, but that’s still 120 C higher than it’s supposed to go. I am surprised at how pale the barium glaze is over it.

13-chalk-beach-terracotta-three-spouted-vessel-with-porcelain-inlay-25cm-x-13cm.jpg

the rest of the pots are here.

2 Comments

  1. I would very much like to experiment with this barium glaze. Would you be willing to share the recipe? By the way I bought one of your pots from Beaux Art in Bath

  2. I worked out this glaze from a book – Ian Currie’s Revealing Glazes. It’s adapted from his very dry coloured glazes – there’s a whole page on barium glazes. I don’t think you should just copy the glaze, it might well not work for you. you should buy the book read up about how barium carbonate works, and experiment.
    the first time I fired my kiln to glaze temperature I had 50 – odd glaze tests in it.
    don’t forget barium carbonate is poisonous, so wash everything, wear a dust mask, etc, etc. also Ian Currie says “if you decide to use poisonous materials in a glaze inside a functional pot, it is your responsibility to ensure it is safe.”

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.