Notes on soft soldering - AH00.19-P-1000-07A
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General
Soft-soldering is a process for creating an inseparable join between two or more metal parts using additional metals (e.g. soldering tin). The solder melting temperature lies below the melting temperature of the metals to be joined and is lower than 450 °C.
The connection is created by wetting the joint locations with hot liquid solder, without melting the parts to be joined.
The joining procedure is assisted by using a flux, which releases surface oxides on the parts to be joined, eliminating and preventing surface films (e.g. greases).
Soft soldering materials
The soldering alloy determines its melting point and thus the working temperature during the soft soldering process. Additives modify the properties. Silver components improve, e.g. the surfaces and joining properties. Ensure that lead-free solder is used.
Soft solders are identified according to DIN EN 61190-1-3 or DIN EN 294453/ISO 9453.
Example: EL SOLD soft solder FLOWTIN TC07 Sn99, 7Cu0.7
The alloy consists of 99.7 % tin (SN) and 0.7 % copper (Cu)
The melting range is 227 °C.
In the electrical system/electronic sector for vehicles, fast solders with a melting point range of approx. 180 °C to 227 °C should be used. These solders are available in the form of wires. They have flux from resins dissolved in alcohol (e.g. colophonium) in their hollow center.
Soldering equipment
Soldering equipment with soldering tips that can reach a temperature of 250 °C to 300 °C are suitable for the repairs specified by Daimler. The aim is to use automatic temperature-regulated equipment (e.g. soldering stations).
Preparation, general
- Use suitable work clothing.
- Use safety glasses.
- Use any available soldering fume extractors, aeration.
- Verify clamping devices and work surfaces.
- Clean soldering tips with small wet sponge.
- Protect surrounding working area from heat damage.
Preconditions for soldering
Soldering points must be clean, free of grease and oxides.