Professional Jewellery Cleaning, Polishing & Refinishing
The item of jewellery is first emeried. Emery sticks and small abrasive wheels on a flexible drive are used. All scratches are removed and an even surface finished is achieved. This is an aggressive process involving the removal of a few microns of metal from the surface. It is important to obtain an even surface, as this influences the quality of the final polished surface. Badly damaged jewellery sometimes even needs to be filed to remove deep dings and scratches.
Embossed, filigree, hollow and engraved jewellery often can’t be either emeried or filed. These types of jewellery require special care and are often given an initial polish using brass brushes.
If the piece of jewellery has been previously Rhodium plated, all the old Rhodium plating must also be removed. This is also the case for Hard Gold plated jewellery.
Once the surface has been returned to an even finish, the actual polishing process can begin. This is normally achieved with a polishing machine, using bristle brushes, cotton mops and felt mandrels. The machine spins the brushes and mops at speed and the jewellery is pushed against the spinning mop.
Not all jewellery is refinished to a polish. Professional jewellers can also reinstate other types of surface finishes. These include; hammer finish, brushed finish, sandblasted finish, Florentine finish and textured finishes.
The brushes, mops and mandrels are charged with different polishing compounds.
The initial polishing is often done using Tripoli. Tripoli is an aggressive polishing compound composed of abrasive and a binder.
After being polished with Tripoli, a finer grit compound is used, such as White Dialux. The same process as the Tripoli is repeated with the finer polish.
Finally a very fine grit polishing compound is used, such as Rouge. The traditional red polishing compound gives the metal a deep shine. All the small scratches should have now been removed and the piece of jewellery is now ready to be cleaned.
In a modern jewellery workshop the cleaning process is normally carried out with an ultrasonic cleaner. Using ultrasonic sound waves, heat and a cleaning solution, all of the built up dirt, grime and polishing compounds are removed.
Other cleaning processes entail the use of steam, wash-out brushes and if the item is to be plated, electrolytic salts which remove even the smallest traces of organic matter. Different workshops use different combinations of these techniques. This is largely a result of acquired traditions.
The piece of jewellery is then thoroughly dried. First with compressed air. Hollow pieces may be left in an absorbent material such as saw dust or absorbent tissue to suck out the remaining moisture.
Rhodium, Gold & Silver Plating
If the piece of jewellery requires plating this is done after the final clean. In fact another round of cleaning is undertaken to remove the last remnants of organic matter before the plating can commence. This involves electro-cleaning, acid baths and rinsing in neutralized water.
Finally the jewellery is inspected. Gem stones are examined to ensure they are secure after the cleaning process. The plating is checked and missed scratches are looked for.
The jewellery is then bagged in zip-lock plastic bags and is ready for collection by the customer.