Most common metals, including mild steel, stainless steel, copper, brass, cast iron, and dissimilar metals, can be joined with silver solder. Because silver is a soft metal, the surface must be hardened before soldering to prevent damage to the article being joined. The easiest way to join these types of materials is to use silver solder. Silver solder has lead removed from it so it will not poison you or your children if it gets into something you eat or drink. It is also non-toxic and won't break down into toxic substances over time. There are two types of silver solder: pure silver and silver-based. Pure silver solder requires melting in a furnace at about 400 degrees F (204 degrees C) for several hours or using a torch to heat it directly. This process is expensive and not very practical for most people. The cheaper alternative is silver-based solder which can be bought in tube form and used like paint. It needs to be heated to about 300 degrees F (149 degrees C) to make it flowable. Then it can be applied to the joint as usual. After cooling, the piece can be cleaned with soap and water.