When thinking of casting, it's widely believed that many items will be exactly the same. True, but also a cast item can be completely individual! To produce more than one item to be exactly the same a mould is made - for instance from, silicone or vulcanised rubber.
Vulcanised Rubber moulds can last 20 years or more but shrink around 5% hence going one size smaller. You have to use a master that will stand 150 degrees centigrade and high pressure for an hour. So in practice your master must be made of metal or similar material. Rubber moulds take a couple of hours to make and are ready to use right away.
Silicone moulds do not shrink and do not need heat so you can mould directly from fragile materials such a leaf or a wax master. But they are hydroscopic and deteriorate in sunlight, are liable to tear if abused and have a life of about 2 years. Silicone moulds take about 2 hours to make and need 24 hour set properly before they can be used.
One-off casts can be produced by sand casting , lost wax casting, cuttlefish casting - these moulds can only be used once. Another form of casting is with PMC. This is a relatively new process and doesn't need excessively expensive tools or equipment, but does allow the maker to produce a 3 dimensional object from silver without the expertise which would be required from a traditional silversmith. The PMC (precious metal clay) is silver mixed with clay and can be formed into a shape and then fired to remove the clay. The item which is left, is silver (either 925 sterling or 999 fine).PMC does shrink by about 10% and the finished item, in my opinion is more brittle than silver wire or sheet - I certainly wouldn't use it to make a ring! - the use that a ring gets over the years, I believe could mean the ring cracking later on it's life. PMC hasn't been around long enough perhaps for this theory to be tested yet.
If I needed to make a starfish as a traditional silversmith, I would cut out 2 starfish shapes, dome them gently and set them back to front. They would then be hollow. Take a look at the starfish earrings that I have made from PMC - they're solid 925 silver and because they didn't take me hours to make (which they could have done if I'd used traditional silversmithing methods), this makes them more cost effective for the purchaser. A lot of PMC artisans create the hole by creating it during the PMC shaping process - I prefer to drill a hole afterwards and natuarlly I solder the jump ring through. PMC workers don't even need to know how to solder but it is most certainly an artform in it's own right.
Having discussed Acid Baths previously - one piece of vital equipment for the sulphuric acid bath is a pair of copper tongs. The heated item of silver needs to be put in / removed from the acid bath. If another metal is used, then any item of silver in the acid bath turns pink! - the acid needs to be thrown away and the 'damaged' pieces require a lot of emery paper to get rid of the pink.
Plastic tongs are also ok to use in the acid bath, but it's best to buy copper in the first place because it you want to pick up a hot item from the soldering block - then quite clearly the plastic tongs won't be any use
- Selling your products / How to sell your handmade silver jewellery / how to sell your jewellery
So, you've designed the most amazing piece of jewellery - but how do you stop someone copying it?
Copyright protects 2 dimensional work - so photographs of your work can be copyrighted.
ACID is a member based organisation raising awareness of Intellectual Property Rights - (IP).
So how do you protect 3 dimensional work such as jewellery design?
You do not have to apply for intelectual property rights, but ensure you keep very good records of when the design was first recorded in material form and when products made to the design were first made available for sale or hire.
This information may be useful if someone challenges your rights in the design or if you believe someone is infringing your rights and you wish to take the alleged infringer to court.
The hallmark is an excellent proof of the year of manufacture - I always keep the first item made!
For items which don't require a hallmark, when I upload the jewellery onto my website I print the page which alwasy prints the 'online' date and the proof is immediately available as to when it was first available for sale. Alongside this, I keep accurate records of how I made the jewellery.