Are you just getting to grips with base metals and how to use them in your jewellery making projects? You may want to learn a little more about the physical properties of base metals, and which ones should be used for certain projects before you go ahead and design your next piece.
What is base metal?
Base metal refers to a type of metal that easily oxidises or corrodes, reacting with hydrochloric acid to form hydrogen (apart from copper). What is the difference between base metals and precious metals? Well, base metal prices are generally less than that of precious metals, simply due to the fact they are more easily found and extracted than precious metals.
Non-ferrous base metals (those that are more resistant to corrosion) have recently seen a growth in popularity amongst jewellers. This is due to their increased reactivity, useful working properties, and lower prices when compared to precious metals. The most commonly used are copper and brass, however jewellery makers also turn to bronze, zinc and gilding metal for practice.
Tips on using base metals in jewellery making
- When it comes to soldering base metals, copper, brass and bronze can all be soldered using silver solder and borax. Copper is more difficult to solder because of its tendency to oxidise.
- Their reactivity allows for a wide range of colouring techniques to be used.
- Their surface is usually quick to tarnish in air.
- Base metals cannot be hallmarked or used in pieces that will be hallmarked.
What are the properties of copper?
Copper has a warm orange colour when polished. However, due to its increased affinity with other metals, its colour changes easily from brown to purple, blue or even black effects. One of the disadvantages of wearing copper jewellery is that it can leave skin green. When exposed to certain atmospheres copper turns to a shade of green or blue. It is often used to strengthen gold and silver. To protect it from corrosion, jewellers oxidise and seal it securely. Use anti-tarnish tabs and bags to keep your copper, brass and other non-ferrous and ferrous metals secure.
What are the properties of brass?
Brass contains 60% copper and 30% zinc and has a higher melting point than both its constituents – 921ͦC – 960ͦC. Brass requires frequent annealing and air cooling to avoid cracking. If the copper quantity is increased, its colour becomes more golden and the metal more malleable. It represents a good choice when working wire structures due to its rigidity after it has been hardened. It is also suitable for designing tools such as punches and pierced templates.
What is gilding metal?
Gilding metal has a warm yellow colour (given by its composition of 95% copper and 5% zinc) and similar malleability and working properties to silver, with a melting point between 899ͦC – 941ͦC. As with the other metals, it is often used to test run pieces to keep the material costs to a minimum.
What are the properties of bronze?
Bronze has a yellow brown colour and is mostly used for casting due to its increase hardness and ability to retain details.
Note: Nickel also belongs to the base metals category but it should not be used in jewellery making as the chances of an allergic reaction are high.
What other metals do you turn to and what have you learnt from using them? Let us know on Twitter and Facebook. Alternatively, stock up on all the bullion supplies you need to create your latest designs.