You should not attempt to melt rubber OR plastic. First of all, rubber- unless you purchase it raw (not from inner tubes or tires or something) will not melt… it’ll BURN. This is bacause it goes through a step called vulcanizing (nothing to do with Star Trek) that prevents it from melting or malforming dur to heat.

At what temperature will rubber melt?

Melting points and ignition temperaturesPlasticIgnition TemperatureWool228°-230°Cotton250°Rubber260°-316°

How quickly does rubber burn?

Without going into a lot of detail about the process, it generally takes between 1 – 2.5 hours depending on melter size and volume of rubber to fully melt the blocks from a cold start.