I KNEW I wasn't the only one who plays Minecraft and TPT here! [Insert some random stuff about being realistic and looking cool here] Oh, and +(n>9000)
don't create any extra borders to represent a black body type situation.
Extra borders outside of the actual shape skews measurements, I suggest just lightly changing the metals' color to glowing, and before it becomes liquid make it turn white hot.
Do not make it in fire mode that this glow is like the glow found on neutrons, photons, and Glow, this would be like an added border type thing.