Group B Lab Data – Week 7

This week, the class completed the first lab in the pottery unit: preparing clay and forming small pinch pots or vessels. Kelly Connole, a Carleton ceramics professor, joined the class over video call to instruct us on both the materials and techniques we would be using. Prior to class, each student received three materials: powdered clay dug from the arboretum, powdered clay from the ceramics studio that is pre-mixed with chemicals to aid in forming and firing, and grog that is used to stop pottery from shattering in the kiln. Finally, each student needed water and a mixing container for hydrating the clay. 

Basic Process

Although there was some individual variation and experimentation in the processes, students followed these general steps to create our pottery: 

1. Hydrate the powdered clay with a few teaspoons of water at a time until a coil can wrap around your finger without cracking. Form the clay into a rough ball. 
2. Place a few teaspoons of grog in the empty container. Roll and coat the outside of the clay ball with grog. Massage the clay to incorporate. Repeat until all grog is combined. 
3. Form the clay into a ball. Press your finger into the center of the ball to form a rough bowl shape with thick walls. Apply water to the rim of the bowl to prevent cracking. 
4. Using your index finger and thumb, pinch and pull the sides of the pot up and out to create your desired shape. Keep the clay steady while turning by resting it in the palm of your other hand. 
5. Optional: add a coil and smooth in against the seam to build height. Set the coil to the inside of the rim to create a neck. 
6. Dry the pots until leather-hard before adding decoration. Dry completely before firing. 

Data Summary

Since all students joined the online lab from our own spaces, every member of my group took their own notes. I’ve categorized the overarching themes into five sections: clay mixing, clay comparisons, pottery forming, decorating, and drying. Each section provides a summary of the group’s experience with that aspect of the lab. The student lab journals can be used for more detailed information into the individual processes of the group members. 

Clay Mixing:

All of the group members had worked with clay before, so we had a rough sense of the texture that would need to be reached when hydrating the powdered clay. At first it was difficult for many of us to eyeball the water content we needed, but after multiple batches of clay it became a little more intuitive. One member recognized the importance of the proper clay to water ratio. Too little water causes the clay to crack and too much water creates a slimy mass that needs to dry before it can be used. 

Clay Comparisons (arboretum versus studio mix): 

The clay from the arboretum was a chocolatey brown color that was reminiscent of freshly dug dirt both in smell and texture. It felt gritty and contained large lumps that had not been sieved out during the pounding process. This made it harder to reach a smooth consistency when hydrated. It was more difficult to form than the studio clay and seemed to crack more. However, this could be due to improper hydration and mixing because the arb clay was the first batch we made. On the other hand, the studio clay was very smooth and workable, reminiscent of what was used in ceramics classes we have taken in the past. One member notes that while the studio clay felt less dry and was easier to mix, the reddish tint made the color less appealing than the arboretum clay.

Pottery Forming:

There were three common takeaways from pottery forming: the difficulty of coiling, inconsistent thickness of walls, and cracking. Coiling was difficult because although clay was being added, it often expanded the pots outwards instead of adding height. This created bowls rather than vessels. Even the group members who had more success with the coils noted that the shape of the pot was not necessarily what they had envisioned. Many of us also found that the walls of the pots became too thin in the process of trying to even out the thickness of the sides. This, along with the cracks that came from the clay being too dry, could potentially cause issues when firing.

Decorating: 

Most of the pots were left undecorated, but there were still a few different techniques used. The first was hand crimping (like on a pie crust) to create a ruffled rim. This was an easy option to do without any tools. Although it created some aesthetic appeal, the design did not add any usefulness to the pot. The second design, geometric shapes carved into the side using a blunt pencil, was more accurate to Early Medieval English pottery, but still only added aesthetic value. 

Drying:

Many of us found that our pots continued to crack as they dried and the moisture evaporated. As they dried, both clays turned lighter colors and smaller imperfections or chunks of clay stuck to the outside flaked off with a bit of pressure. The pots also shrunk slightly, losing about half an inch from the circumference of the base and the rim of the bowls. Interestingly, one group member found that their pots were bone-dry by the end of the day while another found that it took about 24 hours to reach that stage. This could be because of the water content of the clay. Alternatively, because of our lack of experience, they could have had two different standards for what constituted “dry.” 

• 

• 

Major Takeaways

Although there were varying degrees of difficulty, everyone in the group was able to create multiple small pots that could be practically used once fired. The most challenging aspects of the lab were mixing the clay to the proper consistency and controlling the clay during forming (versus the clay controlling us). The group agrees that the arb clay was more difficult to work with than the studio clay, although some found the arb clay to be a nicer color. Firing the pots next week will be a very exciting culmination of the pottery unit. It will be interesting to use this data to try to understand how the pots that survive were mixed or formed and what gave them an advantage in the kiln.