Monday, 27 April 2009

Lead-Free Solder

Most of the advice around lead free solder is to avoid using it. However, lead-free solder is essential for making jewellery (which may have skin contact) or any project that may be in contact with food.

Lead-free solder does require a hotter iron than lead bearing solders, plus it does not flow easily. This is in spite of its relatively low melting point.  It has a pasty state between solid and liquid that is prone to lumps and spikes. If this is not bad enough, it also does not take patina designed for lead bearing solders well.

Those using rheostats with their soldering irons, should get rid of the rheostat (see tips on soldering irons), as they limit the ability of the iron to recover the soldering temperature. The best iron to use with lead free solders is a temperature controlled iron, like the 100 watt Weller, or even a higher powered one like the Weller 200 watt. You can get tips that run at 800F to replace the standard 700F tips. This helps with the higher temperatures needed for the lead free solder. But you should not be vaporizing the solder as that is what could hurt you.

Consider the effects of the flux that you are using. Experimenting with various kinds (see the flux tips) can lead you to one that works better than the others.

As always, good hygiene and good ventilation are required when soldering. Also you should wash your hands well and frequently, and eat in a separate room.