Soldering terminology

In soldering with cored solder, the temperature of the solder brings the flux inside the solder to boil, making it splash apart as soon as the surrounding solder shell melts away, and solder bumps form as a result. To prevent this, a V-shaped incision is made along the axis of the cored solder, allowing the flux to evaporate when the cored solder melts, without triggering explosive solder splashes. However, the incised cored solders cannot be stored for long because the flux oxidizes. Therefore, the incision is usually carried out just before soldering. See also Splashing.