Collection of Samples

Several weeks ago I collected my final samples before returning from Barbados. After interviewing several potters it was discovered that two of five do not use local Barbados clay. When asked for a reason, one potter stated that there was too much variation within the local clay. This means that the content of iron and sand within the clay was not uniform throughout the entire clay deposit. Differences in the variation of the clay body can lead to variance in the firing temperatures of the pottery. If too much iron is present in the sample, the ceramic will fire at a lower temperature with the iron melted out of the clay. This would lead to more shrinkage in the ceramic than desired, and in turn to the breaking of the vessel due to the high heat of the kiln. Too much sand presents an entirely different problem, the ceramic fires at too high of a temperature. This leads to seeping of the ceramic, thus ruining any expensive mahogany tables underneath it. The potter explained that he had lost a whole kilns worth of work because of the local clay and changed sources, as well as complaints from clients about mahogany tables being ruined.

This complicates matters in my research as it tightens my sampling size to only three potters. Despite this, Professor Michael Kelley suggested that I run preliminary tests on a few samples from each potter in order to confirm a pattern. If there is a pattern amongst those tested, further tests will be run on the entire group of samples. This research will be continuing on past the summer, I hope to run my first batch of samples in the following month.

Comments

  1. jgcarnazza says:

    As frustrating as I imagine it is that your sample size has tightened as a result of your findings concerning the content of the clay, I think what you have learned, especially the fact that two of the five potters do not use the local clay, is really interesting!

    And you are definitely not alone in having to make some changes to your sample during your project. I was a little frustrated myself when I encountered issues, but I was happy to see from other people’s blogs that problems like these are pretty common.

  2. I learned a little bit about Irish ceramic materials at my field school this summer, so it’s interesting to read how clay can work elsewhere. I was wondering…when you describe your clay samples, how do you define the color? We used a Munsell Color Chart in Ireland to pick the color of our soils, but maybe that’s just a European Archaeology technique?