IvanVoo

Graduation project — 01

Shio 潮

A modular public bench pressed from crushed oyster shell waste and recycled HDPE — asking what a discarded material is still capable of.

The finished Shio bench in three-quarter view, its speckled composite surface catching the light.

Where it started

The idea came from a walk through Amanohashidate, Japan, past mounds of discarded oyster shell — a by-product with almost nowhere to go.

Back in Sydney, Broken Bay Pearl Farm became the source of the same problem at home: crushed shell waste with real structural potential, if it could be bound into something load-bearing.

Stacked oyster racks and shell waste at Broken Bay Pearl Farm.
Broken Bay Pearl Farm — sourcing the waste stream

Form development

Finding a shape the press could actually make.

  • Concept sketches exploring bench forms, leg geometry and shell-composite panel joints.
  • Concept sketches exploring bench forms, leg geometry and shell-composite panel joints.
  • Concept sketches exploring bench forms, leg geometry and shell-composite panel joints.
  • Concept sketches exploring bench forms, leg geometry and shell-composite panel joints.

Developing the composite

The bench is sheet-pressed from a 75/25 blend of recycled HDPE and crushed shell, engineered to a safety factor of 3 and tested well beyond that — to a safety factor of 10, reaching a compressive strength of roughly 2500 psi.

Because HDPE is usually sheet-pressed and CNC-cut, the shell introduced a new manufacturing constraint. With limited time I pivoted to framed final forms and experimented with sheet-pressing curved arcs — something rarely attempted, because they warp. The embedded shell surprised me: it stabilised the material and prevented the distortion.

Modularity meant the bench could be assembled, repaired and reconfigured in public without specialist tools.

The four flat-pack components of the bench laid out, showing the terrazzo-like shell composite.
Flat-pack components — two legs, a stretcher, a seat

Project specs

Composite ratio
75 / 25 HDPE–shell
Compressive strength
~2500 psi
Engineered safety factor
3
Tested safety factor
10
Shell source
Broken Bay Pearl Farm
Form
Modular public bench, 1:2 scale model
Side elevation of the finished bench showing the arc of the seat and the stretcher joint.
Detail of the pressed composite surface, crushed shell visible through the recycled HDPE.

Exhibited at BEGradEX, White Bay Power Station