What technique enhances the filleting ability in tin-silver solders?

The technique that enhances the filleting ability in tin-silver solders is the proper cleaning of surfaces. Ensuring that surfaces are free of contaminants, oxidation, and impurities is crucial for achieving a good solder joint. Clean surfaces allow the solder to wet and flow into the joint more effectively, creating a strong bond.

When surfaces are not properly cleaned, contaminants can inhibit the solder's ability to adhere, leading to poor filleting and potential joint failure. By removing dirt, grease, and oxidation, the solder can make better contact with the base materials, ensuring that the joint is filled correctly and has the strength necessary for the intended application. Proper cleaning techniques could involve solvents or mechanical means to achieve a suitable surface for soldering.

While other options such as high temperature application, low viscosity, and the use of multiple alloy types can affect soldering processes, they do not specifically enhance the filleting ability in the same direct manner that proper surface preparation does.