Wednesday, January 5, 2011

Technical Topics

I am delighted to be the new technical advisor for PMC Connection. I will be making regular posts to CornerStone on the techniques, technology, and technicalities of metal clays and related materials and issues. If you have a particular issue you want covered or a question you want answered, let me know and I will tackle the topic for you. I will begin with the first installment in an ongoing series on health and safety. I hope you find this series as informative and enlightening as it has been to research and write about.
Mary Ellin D'Agostino


Lora Hart said...

I'd like to know if you think there's a difference between firing in carbon in a square box or a round one. Why would a round container help the sintering process?

Earl Roberts said...

There are a number of possible advantages to firing in a round container v a square container
1.Round fiber container is not prone to cracking like a square one as the expansion is fairly uniform around its circumference.
2. The round container "sees" more of the elements in a kiln where not all walls have elements (i.e. front loading kilns). I suspect this helps uniformity as reported by various users who find they can fire anywhere in the round fiber box whereas they could not in a square pan. This might be a function of the material as well as the shape of the container.

Lora Hart said...

Interesting. Thanks Earl.

Mary Ellin D'Agostino said...

The main advantage I could think of for a square or rectangular container would be to maximize the firing space in a square or rectangular kiln. This is at least partially negated by the potential need to place all items to be fired near the sides and back of the container as Hadar Jacobson recommends for front loading kilns.

Personally, I usually fill all the space in my old rectangular steel firing chamber, but I always heat slowly and fire for a long time to make sure that even the center of the chamber is hot enough for a long enough period of time.

I find it interesting that some of the same people who insist on firing their silver clay pieces for the full 2 hours to get the maximum sintering are often looking for ways to shorten their base metal clay firings. I suspect that after a while more of us will be calling for those longer firings again to get the maximum sintering for the base metal clays as well.