I will be exhibiting my latest pots at the Bonsai Week Bonsai Pots exhibition at the Australian Bonsai and Penjing Collection in Canberra. I will be manning the exhibition Friday 23rd 9am – 12pm and Saturday 24th 1pm -4pm so come and say Hello! I am also bringing some pots for sale.
Here is a preview of my latest pots fresh out of the kiln.
triple glaze 18 x 18 x 14cm
Unglazed BRT 18 x 18 x 14cm
Oval- KRM magnesia 20x16x6cm
Oval double glaze 21x17x5cm
OX Glaze 17×4.5 cm
double glaze 17.5 x 3.5 cm
Distressed 17 x 6 cm
BRT distressed 20x18x6cm
BRT Oval 20 x 18 x 6 cm
Tomato red 30 x 26 x 6cm
Carved 17 x 4.5 cm
distressed multiple slip
Oval, double glaze 21 x 19.5 x 6 cm
Copper Red Glazes
Copper Red Glazes are one of my favourite glazes. The earliest known copper-red glaze occurs on wares made in Shanxi during the Tang dynasty (AD 618 to AD 907). The secret of to how to make these lovely reds was then lost for several hundred years and there is a story about a royal potter taking the secret with him to the grave leaving a disgruntled Emperor.
Pot by Denise Allen 9 x 9 x 4 cm
Copper is one of the oxides that provide colour to glazes. Copper provides a green to turquoise colour to glazes in an electric kiln but can turn a wonderful red in a reducing atmosphere found in a gas or a woodfired kiln. This wonderful red is not guaranteed as copper is quite volatile and the red colour develops as it is cooling, after the pot has reached Cone 10 (approx. 1300 C). If the timing of creating the reduction atmosphere in the kiln is too late then you can end up with cream or pale grey coloured pot with perhaps a smudge of red.
The other complication is that the atmosphere in the kiln is uneven and some areas will have better reduction than others and some areas will be hotter because the air flows around and over the shelves. The best temperature to start reductions seems to be around 800 C. Copper red glazes nearly always “break” on a rim or texture and become cream or pale grey. There are several types of Copper Red Glazes, Ox-Blood or “Sang de Boef”, Flambe and Peach Bloom. Even the names are evocative.
Below are two tiles with identical glazes, the left one fired in a reduction atmosphere in a gas kiln and the right in an electric kiln.
from Greg Daly – Developing Glazes, Bloomsbury, 2013
Electric kilns usually have a programme that controls the firing (the rate of the rise of temperature in the firing eg rise from 800 to 1200 degrees Celcius at a rate of 100 degrees an hour) so they are switched on and then you can walk away and come back to find the firing cycle completed. A gas kilns like I use, needs constant monitoring of the temperature over the 10 – 12 hour firing cycle and the gas is increased or decreased manually as required along with the opening or closing of the damper and adjusting air vents to control the atmosphere in the kiln.
So what is reduction firing? In an oxidising atmosphere (ie. electric kiln) there is plenty of oxygen across the firing cycle but in a reduction firing the unburnt gas is starved of oxygen ( by closing down the damper and the air intake valves) so it seeks to take oxygen from materials in the glaze thus altering their composition. It is quite fun to open the spy hole in the kiln door and seem the characteristic flame associated with reduction, shooting out the spy hole. There is also a particular smell and flame noise to alert you that the kiln is in reduction.
This pot shows just a blush of copper red indicating that I did not get the reduction atmosphere right for greater colour. However, I like this effect.
Experimenting with multiple glazes on one pot can be rewarding and also disasterous. However that is the nature of pottery. Opening the kiln after a firing is like opening Christmas presents…you will get some you love and some that are disappointing.
140mm (h) 120mm
Round pot 150mm(w) 60mm( h)
100mm(w)80mm( h) and 140X80
2 glazes – 150mm(w) 60 (h) round pot
3 glaze combination
3 glaze 280mm(w) 75(h)
I have been invited to sell pots at the Bonsai Society of Sydney Annual Bonsai Exhibition on the 27th and 28th August at the Forestville RSL Club. I have been inspired to push some boundaries on glazes and pot shapes getting ready for this event but also very busy month repotting last deciduous bonsai!
Oxide wash carved 180 x 50
Dry glaze 200×35
Still enjoying experimenting and learning about glazes and clays and pot forms.
Pretty pleased with some recent pots.
Soft Cornered square pot-110mmx55mm
Oval Pot 225 X 65mm
Round Pot 180mmX70mm
Six sided cascade – back probably a bit a of fuming from another glaze on neighbouring pot in kiln
Six sided cascade – front
I have been busy experimenting with new glazes and doing some single firing of pots ie not doing a bisque firing but one slow fire through to a glaze finish. A bit tricky because you need a glaze that can fit the shrink rate of the clay. A pot shrinks about 10% in the bisque firing so a single fire glaze needs to accomodate this shrink. And yes I have had some disasters.
Opening the kiln is a bit like Christmas…you get some presents you love and then there is Aunt Jane who always gives you a shocker of a present!
I have also sold some pots to Ray Nesci Nursery at Dural and Bonsai World at Jilliby so I have been busy doing what I love.