Raku Crackle

Channeling Halloween! A black background generally works when photographing my pottery. On this occasion, while it has produced an interesting image, it might leave the viewer wondering just what it is they are looking at!

I have been thinking of playing with the colours of black and white using a white raku crackle glaze for a while. I had a few attempts while studying at TAFE, but I was never satisfied with the results. Disheartened, it has taken a number of years for me to give it another go. While these results are far from perfect, I am happy with the depth of black achieved in the smoking part of the process, but hope to achieve a more distinct crackle in future work.

Raku pottery has evolved over time with western influence to many different forms. Mostly, I have been experimenting with different forms of naked raku which do not include glazing, rather treating the pots in different ways to produce interesting decorative work on the bare surface of the pot.

However, in this instance, after the pots were bisqued, I coated them with a white crackle glaze then fired them in the gas raku kiln to the temperature 980 degrees celcius. At this point, I donned a welding jacket, mask, and gloves to remove the red hot pots directly from the kiln and place them into bins with saw dust and shredded paper causing the contents of the bin to burst into flames. I put a lid on the bin which extinguishes the flames. The atmosphere around the pot then is devoid of oxygen and very smoky. The thermal shock crackles the glaze where the smoke enters to create the black crackle marks and any clay without glaze turns black.

There is a lot about this process that is serendipitous. Not only can all the elements of the firing be uncertain, outside factors can also come into play. Towards the end of the firing, a breeze sprang up, making it difficult to get the kiln to temperature. However, the most significant uncertainty lies in my inexperience. I have learned a lot this time. I have a number of adjustments I plan to make next time to see what happens.