What material retains heat the best? Answered
I thought of something I could make for an Instructable. To keep the idea until I publish, I'll exclude the actual idea. I need a material for this project that will retain heat from a microwave for ≥20 to ≥30 minutes. It will be about 8x8x1 inches. What can I use for this?
Here are some things I found to be helpful: