Vacuum Furnace Outgassing
Vacuum furnace outgassing is the release of adsorbed gases and volatile contaminants from component surfaces before reaching the brazing temperature. It is necessary to minimize pores within the brazed seam.
When outgassing in the vacuum furnace, you draw off the air and volatile impurities from the component surfaces. This is important because otherwise, when brazing in the furnace, bubbles will form in the seam and the joint will become porous and brittle. Before outgassing, the parts must be clean and grease-free, otherwise it's all for nothing. The furnace is evacuated to a proper vacuum and the parts are heated so that the contaminants come off the surface. How long this takes depends on the material and the component geometry. Leave the parts in the furnace until the vacuum is stable and no more gases are released. Then you can heat directly to brazing temperature without breaking the vacuum.