Qilmeg Doudatcz
SMArchS Computation @ MIT

Week 10 — Molding & Casting

This page documents the process of molding and casting leaves with embedded NFC/RFID components. The original intent was to cast in clear resin; due to material issues, the final cast was done in metal.

Process

Final Result

Cast metal leaves with embedded RFID
Cast metal leaves with embedded RFID. NFC could not be read through the metal.
Demo: NFC not readable after metal casting.

Mold Cases & Intent

I designed and 3D-printed two sizes of mold cases to hold silicone. The goal was to create three sizes of clear blocks with NFC tags embedded inside, so that site-collected artifacts (leaves) could be cast with the tags and later used as physical triggers on an RFID reader platform to launch scenes in a headset.

3D printed mold cases
3D-printed mold cases (two sizes).
Finished silicone molds
Finished silicone molds ready for casting.

Silicone Pour

Mixed and poured silicone into the printed cases to make flexible negative molds.

Silicone mold making process
Silicone mixing and pour sequence.

Casting

Due to an expired resin kit (hardened in the package), I proceeded with a metal cast following the lab’s recitation demo. As expected, NFC does not read through metal.

Metal casting process with leaves
Metal casting process with leaves; original plan was a clear resin cast.

Group Project

Group casting example
Group casting exercise example.

Notes & Lessons Learned

  • Always check resin expiration and pot life before mixing. A pre-test pour in a small cup saves time.
  • For readable NFC/RFID, avoid fully enclosing the tag in conductive materials. Prefer clear urethane/resin or silicone.
  • Keep tag orientation consistent and close to the reader surface when designing the mold cavity.
  • Plan cable-free tag placement (thin wires/antennas can shift during pour—use light adhesive or fixtures).