Saturday, 6 December 2014

Egyptian Paste



The Egyptian Paste course at Hive Shipley finished last week and the final work has been fired with some stunning results. Everyone got to try out  the basic recipe with different additions of oxides or colouring stains, to make beads, cast small pieces from moulds and model pieces by hand. 

 


A few technical notes; the recipe used is:

39 - Nepheline syenite
12 - Soda ash
37 - Flint or fine quartz
12 - Ball clay
  2 - Bentonite

Fired at 990C
  
Colouring oxides:

Purple -1% to 2% Manganese oxide
Blue -1% cobalt carbonate
Turquoise - 3% copper oxide
Yellow/green - 1%  chrome oxide.
Dark brown/black  - 2% nickel oxide
Buff - 2% to 4% rutile




 The black iron oxide was a surprise, it produced pale pinky buff up to about 4%, and when tested at 6% produced a lovely dark olive green! 

We got great results from mixing paste coloured with different oxides together to get a marbled or mottled effect.




The samples painted with Egyptian paste slurry were a disappointment, but did give hints that this technique could work - so more experimentation  beginning with applying the slurry to green ware rather then biscuit.

 
So between now and January I'll have plenty to keep me occupied with more Egyptian Paste tests and preparing for the next ceramics course where students will find out about and experiment with all the glazes and other decorative ceramic materials to discover interesting and exciting finishes for their work.

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