How To Anneal Copper

The copper should be clean and bright, otherwise oxides will form and become embedded in the surface on heat-up, and should be warmed up with a blow-lamp (a kitchen stove will do this at a push) generally rather than at a specific point, although copper tends to spread heat quickly through the metal.

Once a background heat is produced, when the metal shows different colours radiating away from the heat source, then you are looking for a dark red (plum colour) reaching the part you want annealing – it’s like the colours of the rainbow moving from blue through to bright red as the hottest.

Once this occurs quickly immerse the copper you are annealing into a water bath, and that’s it. Job done.

Patina occurs through oxidation, when oxygen starts a reaction with the chemicals present. It is the same process that produces rust.

When copper is heated a coloured coating is formed. This coating is called "scale", and consists of a thin layer of copper oxide on the surface of the copper. Depending on the thickness of the layer and its temperature, the scale can be some very interesting colours, such as red, blue, brown, and pink, and at higher temperatures, black. The effect is quite noticeable on soldering irons with copper tips.

To solder means to make whole, to unite. Metals can be soldered or united together with the use of the appropriate filler metal, also called solder, and the application of heat.

Soldering, brazing and welding are similar but differ in small ways. Soldering uses a lower melting point filler metal than brazing does. Welding differs from soldering in that in welding the base metals are actually melted and fused together, creating a very strong bond.

Soldering copper for jewellery unites the metals without melding them together. Copper is a really hard metal to solder because of the oxidization that forms on the surface.

The basic steps for soldering copper jewellery using a technique called sweat soldering.

Prepare the metal pieces for soldering by cleaning them. Make sure the pieces lie flat. Lay both pieces onto the perforated soldering board. Cut a bit of solder from the solder sheet and put aside. (Solder is the glue that holds the various pieces of metal together. In order for the solder to flow, the metal must be clean – all of it – including the solder and the flux. The reason for this is that dirt, grease, oxides, etc. will create a barrier between the metal and the solder)

Apply flux to each piece, but apply only to the areas to be soldered together. Use the paintbrush to apply the flux.

Place the small bit of solder onto the flux-painted side of the background piece and then place the foreground piece, flux-painted side down, on top of the background piece.

Begin heating the assembled piece evenly to bring the solder to melting temperature. The solder has melted, and it is time to turn off the torch, when you see the foreground settle into the background and there are no gaps around the edges of the united metals. Special note: the torch does not melt the solder; the torch heats the metal, which in turn causes the solder flow.

Using tweezers, lift the piece and drop it into the dish of water to cool it off. Using copper or wood tongs, lift the piece out of the water and drop it into the warm pickle solution. This cleans the piece and frees it of oxides and excess flux from the heating process.