Yes, but to get the panels truly hard, the freezer must maintain a temperature lower than -30°C. Otherwise, the panel will be at the temperature of the freezer (in a liquid state) and just won’t last as long.
FAQ Tag: freezer
Why are the Lab Freezer temperature panels not turning solid?
The PCM inside is NOT below its phase change temperature of -21.5°C/-6.7°F. Make sure that the freezer temperature is always below -30°C/-9.4°F.