Corrosive Soft Solder Flux
Corrosive soft solder flux is an acid-based auxiliary substance formulated with zinc chloride for rapid cleaning of metal surfaces before soldering. It removes dirt and oxide but leaves aggressive residues that must be thoroughly washed off.
Physical-Chemical Mechanism of Action
Corrosive soft solder flux contains acids such as zinc chloride. These acids react with the metal surfaces, removing dirt and oxide, and preparing the surface for soldering. The aggressive acid can bring metal ions into solution.
Metallurgical Relevance & Welding Risks
The aggressive nature of corrosive soft solder flux can lead to chemical corrosion if not washed off thoroughly. This can damage the surface and make soldering difficult or impossible. Additionally, incompletely removed acid compounds on the metal sheet can cause further problems like cracks or zinc contamination.
Workshop Practice & Action Points
Use corrosive soft solder flux only when necessary for cleaning. Dissolve the material in a closed container and apply it with a soft cloth to the metal surfaces. After soldering, you must wash the surface thoroughly with water and a mild cleaning agent to remove acid compounds. Make sure no acid residues remain.