Solder can be made up of metals such as lead, tin, cadmium, bismuth or silver. The type of solder used depends on the task at hand.
There are two basic types of soldering: hard and soft. Hard soldering typically uses a silver mixture and is good for projects such as jewelry making because it provides a strong joint.
Soft soldering uses other types of metals and costs less to perform. It can be used on items like radios and televisions and provides a suitable bond that is strong enough to withstand normal wear and temperatures that are not too extreme. However, this type of soldering still uses lead on a regular basis and is posing a threat to local water supplies.