What it is
Bottle caps are mostly HDPE (type 2) or PP (type 5): tough plastics that make poor filament but beautiful sheets. A sheet press warms flakes or caps between two hot plates until they fuse, then cools them flat under pressure. The result is a marbled panel 2–6 mm thick that can be cut, drilled and sanded like timber.
The plan
Start simple: a 38 × 38 cm clamp heat press (the kind used for printing T-shirts) and a cold press made from the same boards and clamps as our cardboard pulp. Same-day results.
If we ever need thick blocks or compression moulds, the upgrade is an open-source heated hydraulic press, designed to run from a standard 10 A New Zealand socket — and published as such.
What it could make
Tare tags for the refill shop, soap dishes, hand-line winders for wharf fishing, signs, and the layers of a relief map of the Peninsula made from local caps.
Rules
- HDPE and PP are always kept apart. They don’t bond well together.
- Nothing unidentified is heated. Caps without a code go past the plastic identifier first.
- Hot plastic means ventilation, so it runs in the garage, never in the 1868 building.
- Temperatures to validate: HDPE around 170–180 °C, PP around 190–200 °C.
Where it stands
Planned for 2027. It was the first thing allowed to slip this year, so it did. Bring us your caps anyway: sorted stock is what makes the press useful on day one.
Les plans sont gratuits — the plans are free.
