Troubleshooting Slow Warm-Up in Polyimide Heater

https://thermal-elements.quillnesty.com/posts/installing-a-kapton-heater-practical-steps-for-better-heat-transfer

A polyimide heater can solve a simple problem: place useful heat close to a part that needs it. The best result comes from a clear plan. Shape, power, contact, and control all affect the final behavior