All oven-hardening modelling materials are distinguished by the similar chemical reactions that take place during the „burning“ process. The hardening of oven-hardening modelling materials is based on a gelling process and is therefore completely different from the hardening of water based modelling materials: the plasticizer, because of the high temperatures during the hardening process, penetrates into the plastic particles of the moulding material and itself crosslinks into a gel that, after cooling, holds the particles together. Because the plasticizer has a boiling point of about 300 °C, it does not evaporate during the hardening process. An everyday example of a gel process is the binding of a sauce with starch. In this case, the starch takes over the function that the plasticizer has in those modelling materials.