Metal Working Techniques Part 6: Soldering

A lot of traditional craft jewelry is made with a technique called soldering. Most Southwestern Native American jewelry is soldered. But what exactly is soldering?

Soldering is a technique for joining two or more pieces of metal together using a melted metal alloy, called solder. The solder must melt at a lower temperature than the two pieces of metal that are being joined together. There are many different types of solder. Every type of metal has recommended types of solder. The goal is usually to match the color of the solder to the color of the metal, so that it doesn’t show when the piece is finished. It is also important to realize that some types of solder can damage specific metals – for instance solder with lead may be silver colored, but it will actually corrode Sterling Silver.

Once you have the appropriate solder for your metal you need to sort your solders by the temperature that they melt at. Solder comes in different temperature ranges for a very important reason. A lot of times when a piece is being assembled it needs to be soldered several times. The soldering process needs to be planed so that you start with the highest temperature solder and progress to the lowest temperature solder. That way you will not accidentally melt the previously soldered joints.

The other major ingredient that is necessary for soldering is flux. Flux keeps the metal clean while it is being heated and can also be used to help direct the flow of the solder.

The basic soldering process goes like this. Clean the pieces of metal that are going to be joined. Make sure that the surfaces that you want to join are smooth and meet up very closely, with no light showing between them. Put flux between the two pieces of metal and place tiny pieces of solder tightly up against the edge of the piece that is being soldered on.

This graphic shows the basic set-up for soldering a piece.

soldering graphic







So we have discussed solder and flux, but we have ignored a VERY critical part of the soldering process – heat. In order to solder we need a source of heat to melt the solder. The most commonly used sources of heat are an oven or a torch.

The type of oven that can be used for soldering is called a kiln. Whether it is gas or electric, the most important thing is that the temperature control on the kiln be accurate. You want to be able to solder without melting the piece.

The most commonly used type of torch used for jewelry work is probably the oxy- propane torch. This torch uses a tank of oxygen and a tank of propane, hooked together with a special pressure regulator. The pressure that you use and the size of the tip on the torch control the temperature of the torch. It is then up to the operator to make visual judgments about the progress of the soldering process and know when to move the torch, or remove the heat completely.

Soldering definitely takes some practice, but it is one of the most commonly used techniques in jewelry manufacture and it is very important to at least understand how the process works.

Next Time: Granulation