Alternative Ceramic Supply


Materials
  1. Brick Rubble
  2. Granite Offcuts
  3. Dolerite Offcuts
  4. Broken Bisque
  5. Concrete Rubble
  6. Glass Sludge
  7. Wood Ash
  8. Bone Ash
  9. Marble Offcuts
  10. Oyster Shells


Bulk Buy
Ground Works


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      10.  Oyster Shells



      Test tiles using oyster shells glaze blends, fired to midfire (cone 6, left) and stoneware (cone 9, right). Materials were not added to clay bodies due to fluxing or invisibility. Glaze tests (top to bottom): oyster shells glaze alone, +10% brick, +10% concrete, +10% brick & concrete, +30% more oyster shell.



      FIRST LIFE  

                  ORIGINOysters from NSW, SA, and Tasmania

                 MEASUREMENTSVarious sizes and types
      Bottom shell approx. 70mm long
      Top shell approx. 50mm long

                 COLOURInside - pearly white
      Outside - pinky-brown 
      Some have green
                 TEXTUREInside - smooth
      Outside - layered and rough

                FINISH / FEATURESSharp jagged fringe/edge


      SECOND LIFE 

                 COLLECTION LOCATION -37.77429475433713, 144.99811785500683
      -37.76792626698954, 145.0024019882431
      -37.810785036577315, 144.97073600767806
      -37.83207036311241, 144.95581035540098

                  DATE OF COLLECTION
      September 2023

                  SUBURBNorthcote (2 Locations), Melbourne City, South Melbourne

                  COUNTRYWurundjeri Woi Wurrung, Boonwurrung 

                  LOCAL COUNCILDarebin, Melbourne


      MATERIAL INFORMATION

                 COMPOSITION Oyster shells mainly consist of calcium carbonate (CaCO3; ∼95%) in addition to a small proportion of organic matrix proteins (∼0.1–5%) 

      POTENTIAL APPLICATIONS

                 SUBSITUTE FOR
      Calcium Carbonate
      Calcite
      Whiting
                 IN CLAY BODY
      Coarse mesh recommended for sculptural applications, not tableware as unmelted calcium carbonate may convert to calcium hydroxide: the material will likely swell and becomes powdery (popping through the clay body). Minimum 120# may be used in clay bodies as a flux.

                 IN GLAZE      Test as 1:1 substitute for ingredients listed above in a glaze recipe.

      PREPARATION

                 CALCINATION
      550C recommended
                 CUSTOM PREPARATION
      Wash and rinse with water multiple times to remove salt. If fired in an electric kiln with salt present, salt will stick to elements, interior and frame and corrode metal at a rapid rate. Sodium chloride fumes are hazardous.
      Ideally, remove bits of oyster inside.
      It's possible to fire without removing but it may cause smoke and smell in kiln
                 MINIUMUM REQURIED EQUIPMENT
      Mortar and pestle, or hammer

                 RATING
      (Scale of 1 to 5, with 5 being hardest)
      1
                 NOTESOnce calcined, the shells will easily crush/crumble with mortar and pestle. Blitz in a blender/thermomix to a fine powder.

      SAFETY &
      HANDLING

                 HAZARDS
      Caustic
                 SUGGESTED PPE
      Respirator
      Gloves

      SOURCING

                 SEARCHING FOR SUPPLY
      Contact oyster bars, seafood markets, and restaurants/bars with oysters on their current menu.
      Take a labelled bucket into restaurant and ask staff in person to collect oyster shells that are about to go in the bin. On the label have your name, number and 'please collect oyster shells'. Offer to collect or swap over the bucket every 1-2 days to ensure no vermin in their kitchen. 
      If a large quantity is available (ie, oyster bar at market) - ask to see their bins in back-of-house area. If the shell they're served in is not accessible, ask what they do with the top shucked part.

                 WHAT TO BRING WITH YOU
      Take buckets, plastic bags and long gloves.  

                 QUESTIONS TO ASK
      Do any other people collect the shell waste?

                 RECYCLABILITY AS-IS
      Environmental
      • Use in habitat restoration programs. 

      Landscaping/Gardening
      • Use as mulch or addition to soil for balancing ph

                 COLLECTION RECOMMENDATIONS
      Shells will smell - keep the time frame between pick up and washing and calcining to a minimum.
      Be considerate and avoid collection during busy restaurant service times.
      Collection will be best after warm, sunny weather and on weekends.