Unit 3: Soldering

The Chemistry of Solder: Understanding the role of flux and the "wetting" process that creates a molecular bond between metals.

Heat Transfer Dynamics: Why we heat the "work" (the wire/pad) rather than the solder itself.

Cold Solder Joints vs. Ideal Joints: How to visually identify a reliable connection (shiny and concave) versus a failure (dull and beaded).

Circuit Continuity: How a break in a solder joint stops the flow of electrons, and how a "bridge" (short circuit) can damage components.

The "Solder Bridge" Practice: Complete a practice PCB or wire-twisting exercise to master steady hands and timing.

Motor Preparation: Tin the leads of the thruster motors and attach them to the tether cable, ensuring a slim profile that can fit inside the waterproofing housings.

Control Box Assembly: Solder the D-PDT (Double Pole, Double Throw) switches onto the control board, managing the "nest" of wires without melting the plastic switch casings.

Safety Protocol: Maintain a clean workspace using "helping hands," sponges, and proper ventilation.

• The Multimeter Audit: Before any power is applied, students must use a digital multimeter to perform a "Continuity Test."

  • Success Criteria: The multimeter must beep for direct connections and remain silent between separate circuits (proving there are no "bridges").

• The "Tug Test": A physical inspection where the instructor applies light tension to the joints to ensure mechanical strength.