If two pieces of metal are to be joined by silver brazing and are not in contact, how should each piece be treated?

When two pieces of metal are to be joined by silver brazing and are not in contact, treating each piece by heating them separately is the appropriate approach. This technique allows for an even distribution of heat to each piece, which is vital for achieving the correct melting temperature of the brazing filler metal once they are brought together.

Heating each piece separately ensures that both parts reach the adequate temperature required for brazing, helping to create a strong joint when the filler metal flows into the joint gap. This method is particularly advantageous when dealing with complex geometries or varying thicknesses, ensuring that both pieces can expand and prepare the surfaces for optimal bonding.

Coating with filler does not effectively address the separation of the pieces prior to heating, and heating them together would not work since they are not in contact, potentially leading to improper bonding. Mechanical joining is also not relevant in this scenario, as it does not utilize the brazing process, which relies on melting the filler metal to create a bond. Thus, heating separately is the correct method for achieving a successful silver brazing joint under the specified conditions.