Uncle Bill is correct in asking:
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(Thermoplastic: Soft when hot, hard when cold)
Thermosetting plastic: Permanently hardening or solidifying on being heated.)
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If you want to know if a certain material is thermoplastic or thermosetting, just heat it up again (note: this is a Desctuctive Test, possibly non-reversible, meaning that you may ruin your sample!)
If it softens when you heat it up and sets again in a new position, it is a thermoplastic (like Concealex).
If it melts, it is a thermosetting that only sets once during initial manufacturing.