Cleaning Techniques & Tools
Cleaning precious metal generally falls into one or more of 3 categories; casting marks, tarnish and dirt/grime.
We test a tumbler, an ultrasonic cleaner and an ionic cleaner and let you know which is the right tool for the job.
A tumbler performs two main tasks; the removal of marks left in cast jewellery after it is removed from the mould and polishing and hardening the surface of the metal.
A tumbler is a barrel into which the media (we used stainless steel shot), water, detergent and the jewellery to be worked are placed. The barrel is then placed on a set of motorised rollers for 15 minutes to a couple of hours and the shot and the jewellery collide constantly as the barrel rotates. This burnishes (hardens) the surface layer of the metal and removes non-metal from the surface of the work piece.
A tumbler will remove most dirt and grime due to the water and detergent present but it is primarily used for burnishing and giving a wonderful shine to the surface of a metal. It will not remove tarnish.
These two pictures show the white marks left by casting, especially around the eyes and hairline, very apparent in the first and completely gone in the second photo. 45 minutes in a tumbler was all it took.
The final photo shows the stainless steel shot. It contains pins (~ 11 x 1.3mm), balls (~ 3.4mm) and the odd-shaped saucers (~ 7 x 5mm), this is the media that our jewellery is tumbled in.
Other media types include walnut shells, plastic beads, corn cobs, carbon steel, aluminium oxide and even hardwood. They are chosen to suit the type of material to be worked and the desired finish.
The Ultrasonic Cleaner
The body of the ultrasonic cleaner is filled with water and a few drops of detergent. Jewellery is placed into a basket and lowered into the solution. A timer (normally set to 3 minutes) is started and the cleaner produces ultrasonic sound waves in the solution. These waves cause microscopic bubbles to form and blow apart (cavitation) which lifts dirts and oils away from the surface of the work being cleaned. It will not remove tarnish.
These cleaners are able to get into tiny gaps where cloths, brushes etc. are unable to reach.
The Ionic Cleaner
Ionic cleaners use a combination of detergents and electrolysis to remove dirt, tarnish and oxidisation. Silver takes around 5 to 10 seconds to clean, gold takes around 30 seconds using the same leaning solution. They also work well to clean many gemstones, but care needs to be exercised with pearls, opals and other stones that should not be wetted.
They are great at removing tarnish, so don’t clean ‘antiqued’ jewellery or it will lose the deep colour where the tarnish was deliberately applied. Use a cleaning cloth instead.
A great way to clean the surface of bangles, chains, pendants and charms. A chemical is impregnated into the cloth and will remove light tarnish very easily.
It can be a little difficult to get into tiny cracks and crevices to remove the tarnish there, but this makes them ideal for ‘antiqued’ beads and other jewellery with deliberate tarnishing below the surface (that you want to keep!).
An easy to use home cleaner for removing tarnish and is environmentally friendly. Mix about 2 teaspoons of baking soda and a good pinch of table salt into about a cup of hot water (straight from the kitchen tap).
Make sure it all dissolves and place a small square (5cm x 5cm) of aluminium foil into the bottom of a glass/plastic/ceramic (not metal) bowl.
Pour the solution over the foil and place the silver onto the foil (they must be touching for it to work). Swish it around now and then and in a few minutes your silver should sparkle.
The mixture isn’t critical, nor is the time. If your silver is heavily tarnished, you may need to make up a fresh batch and repeat.
Make sure to rinse thoroughly under running water and dry with a soft towel when finished.
The Right Tool
The three identical chains below were dipped into a solution of ‘liver of sulphur’ which causes sterling silver to tarnish rapidly. The spring ring clasp was NOT dipped, the other end of the chain (bottom in photos) was in a mild solution for 90 seconds.
The chains were then given different treatments. The first was tumbled for 30 minutes, the second placed in an ultrasonic cleaner for 3 minutes and the third passed through an ionic cleaner for 5 seconds.
As you can see, the tumbler and the ultrasonic did not remove any tarnish, but the ionic completely removed everything in only a few seconds.
The chains in the tumbler and ultrasonic were then cleaned again. This first with a polishing cloth which worked well on the surface of the links, but didn’t get into where the links join together. The second was dipped into a solution of baking soda (as described above) for 10 minutes and came up really bright and clean.
|Removes Casting Marks||Yes||No||No|
|Removes Dirt / Grime||Most||Yes||Yes|
|Safe for gemstones?||No||Some||Most|