5.4: Troubleshooting
- Page ID
- 299297
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Centering: The Foundation of Wheel Throwing
1. Clay Keeps Going Off-Center:
- Cause: Uneven pressure or improper hand positioning.
- Solution: Anchor your elbows to your torso to stabilize your movements. Apply equal pressure from both hands when coning up and down. Ensure the clay is well-wedged to remove air bubbles that can destabilize it. Recenter by starting again with steady, gentle movements.
- Tip: Keep the clay moist to reduce friction between your hands and the surface. Reapply water or slip if it begins to dry out.
2. Wrist Strain:
- Cause: Poor posture or over-reliance on wrist movements rather than using your whole arm.
- Solution: Sit with a straight back and your elbows supported by your thighs or tucked into your sides. Use your entire upper body to press and guide the clay, rather than isolating the movement to your wrists.
- Tip: Stretch and warm up your wrists before a throwing session, and take breaks to avoid fatigue.
Creating Basic Forms: Cylinders, Bowls, Plates
1. Walls Too Thin:
- Cause: Overworking the clay or applying uneven pressure during pulling.
- Solution: Pull with consistent, gentle pressure and avoid over-thinning the walls. Focus on lifting evenly from the bottom to the top in each pull.
- Tip: Check wall thickness regularly with your fingers or a caliper to ensure uniformity.
2. Collapsing Forms:
- Cause: Weak structural support from uneven walls or too much water.
- Solution: Compress the base and walls during every step to strengthen the structure. Avoid over-wetting the clay, which can weaken it.
- Tip: Use a rib tool to gently compress and refine the walls after pulling them up, ensuring they remain even and stable.
Advanced Forms: Lidded Containers, Teapots, Vases
1. Lid Doesn’t Fit:
- Cause: Improper measurement or lack of allowance for shrinkage during drying and firing.
- Solution: Use a caliper to measure the gallery and match the lid’s size exactly. Account for shrinkage by making the lid slightly larger than the opening.
- Tip: Test the fit when the pieces are leather-hard and make adjustments by sanding or trimming as needed.
2. Teapot Spout Drips:
- Cause: Poor spout alignment or a rounded spout lip.
- Solution: Ensure the spout is angled slightly upward and the lip is sharp enough to cleanly cut off the flow of liquid. Test the pour before firing and make adjustments if necessary.
- Tip: Use a small coil of clay to reinforce the base of the spout for added stability.
General Wheel-Throwing Challenges
1. Uneven Drying Leading to Cracks:
- Cause: Uneven wall thickness or improper drying conditions.
- Solution: Ensure consistent wall thickness during throwing. Dry pieces slowly and evenly by covering them loosely with plastic to prevent rapid moisture loss.
- Tip: Place pieces on a porous surface like a plaster bat to help draw out moisture uniformly from the base.
2. Warping During Firing:
- Cause: Uneven compression or tension in the clay body.
- Solution: Compress the base thoroughly and ensure all areas of the piece are evenly supported during drying and firing.
- Tip: Use a flat shelf or kiln props to prevent sagging or deformation during firing.
3. Clay Detaches from the Bat:
- Cause: Inadequate adhesion at the start or excess water during throwing.
- Solution: Firmly press the clay onto the bat and ensure the bottom is sealed to the wheel head. Avoid over-wetting the base while working.
- Tip: Use a sponge to remove excess water from the bat and base if slippage occurs.
4. Trimming Issues:
- Cause: Uneven leather-hard stage or improperly centered trimming.
- Solution: Wait until the piece is evenly leather-hard before trimming. Re-center the piece carefully on the wheel and secure it with clay lumps or a Giffin Grip.
- Tip: Lightly score the surface before trimming to create a guideline for consistent removal.