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Woodturning The Hollow Burl

 

Woodturning The Hollow Burl – Embracing Nature’s Chaos

Burl wood is one of the most prized and unpredictable materials for woodturners. Its wild grain, swirling eyes, and hidden voids make each piece a unique challenge—especially when hollowing. A hollow burl form can become a stunning organic sculpture, vessel, or lamp base, showcasing the wood’s natural drama.


Step-by-Step Process

1. Selecting the Burl

  • Ideal Species: Maple, black walnut, redwood, or oak burls (known for intense figuring).

  • Check for Defects: Look for cracks, rot, or bark inclusions—these can add character or cause failure.

  • Stabilization Needed? If the burl is punky, consider stabilizing with thin CA glue or resin before turning.

2. Mounting the Burl

  • Secure with a Faceplate: Burls often lack a consistent center, so screw into solid wood (avoid cracks).

  • Use a Heavy Grip: Burls can be unbalanced; slow speeds (300-600 RPM) reduce vibration.

  • Alternative: Embed in a waste block for safer turning if the burl is irregular.

3. Rough Shaping the Exterior

  • Start with a Bowl Gouge or Carbide Tool: Remove bark and establish a general form.

  • Follow the Natural Shape: Let the burl’s irregularities guide the design—organic asymmetry is key.

  • Leave Extra Thickness: Burls can have hidden weak spots; keep walls thicker than usual (15-20mm).

4. Hollowing the Burl

  • Tools for Hollowing:

    • Small Hollowing Rig (for deep reaches).

    • Curved Carbide Tools (for navigating voids).

    • Flexible Shaft Tools (if working around internal defects).

  • Expect the Unexpected:

    • Voids may appear—incorporate them rather than fight them.

    • If the piece becomes too fragile, fill voids with epoxy (clear or tinted).

  • Wall Thickness: Aim for 5-10mm final thickness (depends on stability).

5. Refining the Form

  • Shear Scraping: Smooth tear-out-prone areas with a light touch.

  • Texturing (Optional):

    • Wire brushing enhances grain contrast.

    • Carved grooves mimic natural fissures.

  • Natural Edge Preservation: If keeping bark, stabilize it with CA glue or resin.

6. Drying & Final Adjustments

  • Dry Slowly: Burls crack easily—seal with anchorseal or DNA soak for controlled drying.

  • Re-turn if Needed: After drying, remount and fine-tune shape/surface.

7. Finishing

  • Oil for Depth: Tung oil or Danish oil to pop the grain.

  • Resin Highlights: Fill cracks with colored epoxy for contrast.

  • Wax or Lacquer: For a protective sheen.


Design Ideas for Hollow Burls

  • "Burl Vortex Vessel" – A swirling, asymmetrical hollow form with a natural edge.

  • "Luminous Burl Lamp" – Hollowed with LED lighting to highlight grain and voids.

  • "Floating Burl Bowl" – A thin-walled, irregular-shaped bowl with live edges.