Metalsmithing for beginner jewelry makers: soldering methods

What is soldering? How do you solder two pieces of metal together?

When metal is heated, its crystalline structure expands making molecular spaces between the expanded crystals.

Soldering is introducing an alloy that is fluid before the melting point of the metal being soldered and therefore flows into the spaces of the expanded metal bonding the crystals together. That’s why you can bond precious metals together by means of soldering them.

Solder is an alloy (containing a proportion of the precious metal) that melts below the melting point of the precious metal.

There are different kinds of solder: soft, medium and hard. Soft solder melts at a lower temperature than hard solder.

Tips for soldering

• All the surfaces must make a thight fit and touch “snuggly” against each other.
• The surfaces must be clean and oil-free, file or sand them before soldering them.
• Solder has to be cleaned too before using, sand it a bit until the tarnish is removed before cutting paillons.
• Use flux to protect the metal from oxidation and to aid flowing.
• The joints or surfaces being soldered must be heated evenly and reach simultaneously soldering temperature.
• Heat should be directed to the surfaces being joined and not exclusively on the solder, solder flows when the nearby metals start reaching its melting point.
• Solder will flow towards heat, so you can draw the solder through a joint by moving your torch.
• Use just enough solder to join pieces of metal together, practice until you know beforehand how much solder is enough.
• To see solder flow, its best to do it in a dimly lit area.

Soldering methods

The most frequently used soldering method. You can put the chips between the joint, in the slot, or just sitting on top of it. It will depend on the shape of what you are soldering.

Put flux on the chips and light your torch. To start, heat the surrounding area of the jewelry being soldered. If you strike the piece with your torch just after putting the drop of flux, flux will react quickly bubbling and fizzling away and that can make your chips move out of position.

After the bubbling has started, direct the torch toward the metal and move it to heat the whole piece evenly. As the metal starts changing color, put the flame on the smaller area subject of soldering moving it to heat the two surfaces being joined until solder flows.

You can direct solder towards any segment that is being left unsoldered by pointing your torch to that area. Quench in water and pickle.

2. Sweat soldering

This method is used for joining two pieces of sheet metal, for example when doing overlay.

Place the two metals in their position and put chips of solder between the two surfaces.

Chips should be placed evenly along or around the metal so that all chips flow and solder is drawn everywhere, without leaving any gaps between metals. Again you can direct the flow of solder by moving your torch.

Start by heating the surrounding areas around your charcoal and after flux bubbles, apply your torch on the metal. Move the torch around the metal surface particularly the one at the bottom. As soon as solder flows, move your charcoal to check that there are no gaps between metals.

Otherwise, after solder flows take a look and see if there are gaps in between metals. Add a tiny bit of flux on the gaps and heat again until solder flows and joins all the surfaces.

3. Probe or pick soldering

Cut a medium-sized chip of solder and dip it completely in flux. Put the chip on your charcoal and light your torch.

Place the flame right on top of the chip and see it start “curling” itself to a nice round probe (ball).

Place the probe on the joint you want to solder and proceed as explained in soldering with chips. You can make bigger or smaller probes by cutting bigger or smaller solder chips, depending on the size of the joint; or you can place several probes on surfaces being joined.

While in my jewelry lessons, I used to make lots of soldering exercises to practice the different methods; but more importantly, I wanted to learn how to determine the right amount of solder needed to do the job.

Knowing how to work out the correct amount of solder to make neat joints is a key step in quality jewelry making.

Happy soldering!

Next is a fun part: forming metal to make a ring. Look at two methods for shaping metal to make your first two rings, click here.

< Back to annealing metal.

References: McCreight (2004)

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