In this Instructable I fix my multi-meter plug with some thermoforming plastic. You can apply this repair to other items specific to your needs or you can make plastic parts for your projects. The stuff I am using is called ShapeLock but there are other brands out there. It come in little plastic pellets and when heated they become clear, malleable and soft. You can then shape it anyway you want, once it cools is becomes hard and opaque, which then can be sanded, filed and machined.
This stuff is super strong and durable, so the objects you make will last as long as you don't subject to high heats.
Step 1: The Item for Repair
The leads on my multi-meter broke where the plug meets the wire, just from flexing and stress over time. I re-solder the wire to the plug and will use ShapeLock to protect the wire from breaking again near the plug.
Step 2: Working With ShapeLock
I heated some water in a kettle and pour it into a container. Then I added some pellets until they turned clear, using a stick to stir the pellets, they stick together and are ready to be shaped around the plug. When the plastic started to harden I put it back into the hot water until it became clear again, I did this until I finished molding the plastic around the plug.
Once I was happy with the plug that I shaped, I let the plastic cool, I used some cold water to speed up the process.
The end result was very strong and ready for use again!
Step 3: Video
Here is a video I did of the whole process.