Rebuild a Stripped Screw Hole in Plastic With Copper Wire and Heat
The Problem
Screws that thread directly into plastic — appliance housings, vacuum parts, power-tool casings, toys — strip easily. One over-tightening and the plastic threads shear, the screw spins in place, and the part hangs loose. A plastic boss can't be re-tapped the way metal can, and the usual outcome is replacing a part that's otherwise fine.
The Technique
- Cut a short length of thin bare copper wire — a single strand pulled from scrap electrical cord works.
- Wrap it around the screw a few turns, seating the wire down into the thread grooves so it follows the spiral.
- Grip the screw with pliers and warm it briefly with a lighter. A few seconds is enough — you want it warm, not glowing.
- Drive the screw back into the stripped hole while it's still warm. The heat softens the plastic immediately around the hole, and the copper-wrapped threads press a new, slightly larger thread pattern into it.
- Let it cool completely before putting any load on the part. The plastic hardens around the copper and the screw holds firm.
What You'll Need
Thin bare copper wire (a strand from lamp cord or any scrap wire), a lighter or other small flame, a screwdriver, and pliers to hold the screw while heating it.
Pro tip: This is a light-duty fix — right for a cover panel or a housing screw, not for anything structural or under repeated stress. For a hole that has to keep working hard, a properly sized threaded insert or the next screw size up is the durable repair.
Safety note: Hold the screw with pliers, never fingers — it heats fast. Keep the flame off the plastic itself and work in a ventilated spot; overheated plastic releases unpleasant fumes and a scorched boss is weaker than a stripped one.