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Short Summary
Main recommendation: Solder electrical wires with rosin core electrical solder (60/40 lead solder preferred), using rosin paste flux, a soldering gun or iron with a clean tinned tip, and heat shrink tubing with silicone dielectric grease for a waterproof, permanent connection. The video walks through the five-step process of stripping, adding heat shrink, splicing, soldering, and sealing the joint.
Key Points
- Use electrical solder, not metalworking silver solder, which has an acid core that can eat through wire insulation and cause a short.
- Lead solder flows into wire strands more easily and melts at a lower temperature than lead-free solder, so it is the speaker's preference, with lead-free being more environmentally responsible but harder to work with.
- Rosin paste flux (non-acidic, made from tree sap) protects the copper from oxidation, which otherwise makes soldering difficult and can create a bad connection.
- A soldering gun suits thicker wires and car work, while a soldering iron with a narrow tip suits small gauge wires and circuit boards.
- Good joints show wick-through of solder, visible strand outlines, no bare copper, and no large globs; a cold solder is the most common mistake.
Details Worth Noting
- Concrete instructions: Wear safety glasses; keep the iron away from flammables and place non-flammable material under the work so dripping solder does not start a fire; work in a ventilated area or use a fan; clean the workstation and wash hands afterward, especially before handling food, since solder contains lead.
- Concrete instructions: Strip wires with old-fashioned strippers set to the matching gauge notch (e.g., 12 gauge), stripping roughly equal lengths on each wire; if any strands break, cut and re-strip rather than leave strands missing.
- Concrete instructions: Choose the thinnest heat shrink that fits over the wire and slide it onto one wire before splicing, moving it away from the solder area so heat does not shrink it early.
- Concrete instructions: Splice either by intermeshing unraveled strands and twisting, or with a Western Union (alignment) splice: make an X, then spin each wire around the other tightly, tucking copper ends flush so they cannot pierce the tubing.
- Concrete instructions: Rub rosin flux onto the wire, heat the gun while wiping the tip on a damp sponge, tin the tip with a little solder and wipe to a thin layer, then place the tip under the wire, feed solder at the top so it wicks through the strands, and remove heat once coated; let the joint cool fully before moving it.
- Concrete instructions: Apply silicone paste or dielectric grease over the joint, slide heat shrink over it, and heat from the middle outward with a heat gun or lighter to push excess grease out and seal the connection.
- The speaker's homemade tip method: one dollar of seven-strand non-insulated wire yields about 14 tips versus about five dollars each for store-bought tips.
- Portable butane torches with solder-melting adapters are an option where electricity is unavailable.
Bottom Line
Reliable wire soldering comes down to correct solder, flux, a clean tinned tip, heating the wire rather than the solder, and sealing the joint, all done safely.
