Over-molding Wires with Hot Glue and 3D Printed Molds
Water infiltration is a persistent issue, especially when it comes to wire splices in damp environments. Traditional methods like electrical tape often fall short in providing adequate protection. While heat shrink tubing is a popular solution, Print Practical explored a different approach: over-molding with a hot glue gun. This method offers both electrical isolation and mechanical support for wire repairs, making it an attractive alternative for those working in challenging conditions.
The idea came from a video showcasing a commercial tool used in automotive repairs for protecting spliced wires. The tool features a machined aluminum mold and a standard hot glue gun that fills the mold with plastic, sealing the splice. Inspired by this, Print Practical decided to 3D print custom molds at home to achieve the same results. However, the first attempt was less than successful. The hot glue stuck to the PETG mold, making it difficult to separate the two, and the glue remained firmly attached to the mold even after it was pried open.
Undeterred, Print Practical tried again, this time applying a thin layer of vegetable oil as a release agent inside the mold. This adjustment made a significant difference; the mold opened easily, and the over-molded splice proved to be watertight, surviving a saltwater bath without any leaks. Encouraged by the success, Print Practical went on to repair a frayed iPhone cable, reinforcing a weakened section with the hot glue over-molding technique, thereby extending the cable’s lifespan and improving its durability.
This DIY approach to over-molding wire splices demonstrates how simple materials and techniques can provide effective solutions for common problems, especially in environments where moisture and mechanical stress are concerns. With a little ingenuity and experimentation, Print Practical successfully adapted a commercial technique for home use, offering a reliable way to protect and support vulnerable wire splices.
Read more: Over-molding Wires with Hot Glue and 3D Printed Molds
