luckilly I work in a studio with molten metal and glass. For both glass and metal, when they reach their melting points you garb to two ends and pull them for as long as needed, This causes a "shock" in the metal or glass, basically when you shock it that when it is extremely hot and it is exposed to something much colder like the air we breath, It causes an instant cooling of the materials and the metal or glass becomes instantly a solid and room temperature or colder. The reason the metal doesn't break is because the shock also makes the material very strong and the tensil strength of metal is naturally very strong.
