CCE Selection & Application of Materials & Equipment for Ceramics 4 — Questions and Answers
Question 1: What is the purpose of a bisque firing before applying glaze?
- To vitrify the clay body completely
- To burn off organics, increase porosity for glaze absorption, and add handling strength (Correct answer)
- To melt the glaze onto the surface
- To shrink the piece to its final dimensions
Correct answer: To burn off organics, increase porosity for glaze absorption, and add handling strength
Bisque firing burns off organic matter, creates a porous but strong structure that absorbs glaze evenly, and makes the piece easier to handle during glazing.
Question 2: Which sieve mesh size would be used to produce the finest glaze slop with minimal coarse particles?
- 40 mesh
- 80 mesh
- 120 mesh
- 200 mesh (Correct answer)
Correct answer: 200 mesh
A 200-mesh sieve has the smallest openings, removing the finest coarse particles and producing the most uniform glaze particle suspension.
Question 3: Which clay body characteristic makes porcelain more difficult to throw on the wheel compared to stoneware?
- Higher shrinkage rate only
- Low plasticity due to fine particle size and minimal iron content (Correct answer)
- Higher grog content
- Coarser particle structure
Correct answer: Low plasticity due to fine particle size and minimal iron content
Porcelain's fine kaolin particles have low plasticity, making it less responsive to the potter's hands and more prone to collapsing during throwing.
Question 4: When using a ball mill to prepare glaze materials, what is the primary benefit over hand-mixing?
- It adds flux to the glaze automatically
- It reduces particle size uniformly and blends materials more thoroughly (Correct answer)
- It adjusts the specific gravity
- It removes colorants from the glaze
Correct answer: It reduces particle size uniformly and blends materials more thoroughly
Ball milling grinds materials to smaller, more uniform particle sizes and ensures thorough mixing, resulting in smoother melt and more consistent glaze surfaces.
Question 5: What does the Orton cone number indicate in ceramic firing?
- The exact temperature in Fahrenheit only
- The heat-work (combination of time and temperature) experienced by the ware (Correct answer)
- The speed of the firing ramp
- The clay body's iron content
Correct answer: The heat-work (combination of time and temperature) experienced by the ware
Orton cones measure heat-work — the cumulative effect of both temperature and time — which is more relevant to ceramic maturation than temperature alone.
Question 6: A ceramist wants a matte glaze surface. Which oxide addition is most effective for matting a glaze?
- Potassium oxide (K₂O)
- Barium carbonate or titanium dioxide (Correct answer)
- Sodium oxide (Na₂O)
- Lithium carbonate
Correct answer: Barium carbonate or titanium dioxide
Barium carbonate and titanium dioxide promote micro-crystallization or surface devitrification during cooling, scattering light and producing a matte surface.
Question 7: Which type of kiln furniture is specifically designed to support plates and flat ware while minimizing glaze contact marks?
- Kiln posts
- Plate setters (flat setters with prong-type stilts) (Correct answer)
- Kiln shelves
- Bead racks
Correct answer: Plate setters (flat setters with prong-type stilts)
Plate setters with pronged stilts support the rim of flatware at minimal contact points, reducing the glaze contact area and leaving only tiny marks on the foot.
CCE Selection & Application of Materials & Equipment for Ceramics 4
What is the purpose of a bisque firing before applying glaze?