Topic summary
Oxidizing flame
Extracted from the Wikipedia article Oxidizing and reducing flames.
Oxidizing flame
If the flame has more than enough oxygen, an oxidizing flame is produced. When the amount of oxygen increases, the flame shortens due to quicker combustion, its color becomes a more transparent blue, and it hisses or roars. With some exceptions (e.g., platinum soldering in jewelry), the oxidizing flame is usually undesirable for welding and soldering, since, as its name suggests, it oxidizes the metal's surface. The same principle is important in firing pottery.