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Lead-free solders are more aggressive to steels and can damage internal parts of ovens, particularly if solders containing silver are used. Some, but not all wave soldering machines can be “converted” to operate with lead-free solders and manufacturers should consult their machine vendors to determine if they can be modified to use lead-free solders.

A suitable “lead-free” flux will be required as fluxes designed for tin/lead are usually very poor. Fluxes designed for tin/lead wave soldering function at the temperature at which tin/lead processes are carried out. Lead-free processes are at higher temperatures and so fluxes designed for tin/lead will be consumed and thus much less effective at the higher temperature at which lead-free solder wetting occurs .

As with surface mount, the temperature profile will need to be optimised for each PCB design.

It is advisable to regularly analyse the solder until it is clear that no significant undesirable changes will occur. The use of tin/lead terminated components will contaminate the solder and can quickly increase the lead content to above 0.1%.

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