The process below is a guide to how Scottish Jewellery is made, this guide covers the basic production process. Please remember that Scottish made jewellery may have extra processes involved like enamelling which adds to the costs of manufacturing. Scottish made jewellery is expensive compared to imports because of the high levels of manual labour needed to manufacture it. When you purchase a piece of Scottish made jewellery you are paying for Scottish craft peoples’ labour and skills as well as the material.
The origins of the lost wax process have strayed in ancient times, but it has been used for thousands of years to produce objects in metal; which could not be produced any other way. It permits anything that can be modelled in wax to be converted into metal.
It is believed that the ancient Egyptians used the lost wax method to make their jewellery. They used bee’s wax to make a model, surrounded it with clay leaving a hole to allow the wax to be escape once fired, this would have left behind a clay mould ready to be filled with fine gold.
While wax patterns were originally modelled by hand, and this can still be done, it is now possible to cast wax into moulds as well, so that multiple copies may be made even though the wax pattern is lost in the process. Modern synthetic rubbers have been developed which capture very fine detail.
After the wax model has set and dried the model is attached to a stick of wax via the wax models sprue. Once this process of attaching the wax models to the stick is done it is called a wax tree.
There could be as many as 50 + wax moulds attached to one stick of wax, so around 50 pieces of jewellery can be cast at once.
Once the wax tree is complete it is surrounded with a material that will cover and surround it when wet and withstand high temperatures when baked in a kiln. This method is called "investment" casting.
The dry ingredients of the investment powder are mixed with water and poured into a container or "flask" surrounding the wax tree model, which is attached to a rubber device which holds the wax stick part of the wax tree pattern.
Jewellery flasks are generally placed in a vacuum chamber while this mixture is still fluid, where they are boiled at room temperature to remove air-bubbles clinging to the models. It is helpful to de-air the investment mixture before pouring it over the wax models, in order to reduce boiling-over when vacuuming.
Once the plaster mixture has set hard, the flasks are placed in a kiln, slowly heated to between 1000 and 1250 degrees F, and held at that temperature until all wax residues have disappeared. The place where the wax was in is now a void- hence the "lost wax" designation for this process.
The metal is then melted and the flask mould is filled with liquid silver or gold. The flask is then allowed to cool, then the plaster mould is broken away, revealing the metal part, which faithfully reproduces every detail of the original wax tree.
The raw castings are now removed from the tree and now must be hand prepared. The jewellery is now sawn to remove the sprues, shaped, sized, filed and sanded.
If the piece is to be a Cufflink then it must be soldered to attach the cufflink T-bar (the part that goes through the shirt)
After soldering the piece is dipped in acid for 30mins to remove the oxidation, this leaves the piece very dull and white looking so yet another process is employed.
Here the use of enclosed barrels filled with small cones, soap and water are used to remove most of the file marks from the early stages of production as well as giving the piece a smooth surface. This process still leaves the jewellery dull and grey in colour. To compensate steel shot, soap and water are used to give the jewellery a deep silver shine.
The next process is hand polishing. Here the jewellery receives a brilliant shine by the use of hand polishing. We use mops which rotate on a spindle at 3000 revolutions per minute.
A cutting compound is then added to the mop which has the effect of removing the surface layer of metal from the jewellery. With the use of a second softer mop and a Rouge compound, the jewellery receives a brilliant shine.
To remove the polishing compounds used in the polishing process we use an ultra-sonic cleaning tank.
Here with the use of hot water, soap and vibrations from the tank the polishing compound is removed to leave the pieces sparkling.
After this stage the jewellery is left to dry and is then inspected and boxed ready to be shipped to the customer.