To begin, it is probably best to outline the traditional way of making an item of jewellery.
There are hundreds of designers around and hundreds more very skilled artisans whose workmanship is so good that it would take you and I many years to acquire their knowledge and techniques.
They use precision tools and laboriously work the metal to create their masterpieces. You can do that too, using sheet metal and wire. Many local communities run jewellery courses where you can learn all the basics.
You would learn to cut sheet, use needle files to refine the surface and edges, planish surfaces with a hammer, solder components together and a variety of other techniques. In essence, you would become a silversmith or goldsmith over a period of time.
Many of these items would be one-offs but others would become MASTER patterns from which subsequent reproductions would be cast.
In order to make replicas one first needs to make a mould of the master. This is normally a two part rubber sandwich, which is vulcanised around the master.
Wax is then injected into the rubber mould to create wax replicas of the master. The purpose, of course, is that you can make as many reproductions of your original piece as you want.
The waxes are then mounted onto a wax core using a miniature soldering iron. This forms a “tree”. The tree is then placed inside a metal flask and sealed, apart from the top. Investment slurry poured into the flask and allowed to “set”. The rubber base that sealed the bottom of the flask is removed and it is put into an oven where the wax is melted out.
Over a period of around 12 hours the flask heated to about 1400 degrees centigrade, cooled a little, and then transferred from the oven to the casting machine. The gold or silver is then melted and cast into the flask. This is often done under a vacuum to ensure complete filling of the mould cavities.
After cooling for a few minutes the flask is then “quenched” in water and most of the investment around the cast metal items falls away, leaving a tree of metal that was once the wax tree. This investment mould can only be used once, hence the derived term “lost wax process”.
The metal items on the tree are then snipped off, fettled to remove surplus metal and polished to produce a beautiful piece of jewellery.
BUT, there is another way to make one-off pieces of your own.
It still involves using the lost wax process above but, instead of making a metal master and then a mould, you would create your masterpiece in WAX.
The great thing about this is that jewellers wax is flexible, malleable, carvable and easy to work with. If you make a mistake you can fill it or you can carve away more wax. The possibilities are endless.
Having made your wax model all you now need to do is get someone to cast it for you. That is unless you want to invest many thousands of pounds or dollars in casting equipment.
There are many firms that will do casting for you in most metals. You will have to pay a casting charge and the value of the metal used. This would provide you with a “raw” casting that would still look pretty ugly in its unfinished state. So you would then decide if you wanted to fettle and polish the item or get the caster to do it for you at extra cost.
Whatever you do there is a good chance that your unique piece of jewellery will have cost you a bit less than you might have paid in the high street.
Jeremy Gilbert
http://www.stjustin.co.uk
http://www.stjustin.co.uk/cornish-handmade-jewellery/shopdisplaycategories.asp?id=2&cat=Silver+Jewellery
polished parts investment casting 
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