동배관 용접이 어려운 분들은 이 영상을 한번 보세요(동배관 브레이징 1편)

The following is excerpt from a theoretical book on brazing. I'll leave it here for those who find my explanation insufficient. Brazing is a metal joining method that involves melting and pouring a filler metal (usually silver or copper solder) into the gap between the base metals without melting them. Brazing is typically performed above 450°C (1000°F). (Below 450°C corresponds to soldering.) The characteristic is that the base metals do not melt, only the filler metal melts. The ideal gap is approximately 0.05 to 0.12 mm. If the gap is too narrow, the filler metal will have difficulty penetrating, and if it's too wide, capillary action will weaken, reducing strength. When the base metals are heated to the melting temperature of the filler metal, the filler metal will readily wet the surface and be drawn into the narrow gap through capillary action. After cooling and solidifying, it forms a strong metallic bond.