Dennis
22-11-2010, 07:55 AM
Silver is prized for its beautiful white colour, but when exposed to pollutants in the air it will gradually darken due to the formation of silver sulphide. This process can be retarded in a closed box, or polythene bag by the use of commercial Anti-Tarnish Strips, which absorb sulphur compounds, or be reversed by the use of Silver Dip. Tarnish can also be removed electrolytically if placed in contact with a clean piece of aluminium, or some kitchen foil in a hot solution of baking soda, or soda crystals. Some add a drop of washing up liquid and a pinch of table salt. The optimum time for immersion is about four minutes, after which the dark colour will have been transferred to the aluminium. Any longer and the silver will gradually turn grey again. Set gemstones are generally safe except for those which are porous or have been enhanced with oil, for example opals , pearls, coral, turquoise and lapis, but a mistake can be costly.
Silver will darken in bleach and strong detergents too, due to the formation of silver oxide. This is best removed by re-polishing, or by gently heating and pickling. By the way, don’t ever wear a silver necklace while floating in the Dead Sea.
As with many things in life, while some people work hard to keep their silver bright, others prefer just the opposite, which takes us to the subject of patination…
Patination can be brought about by sulphur containing compounds such as liver of sulphur, ammonium sulphide and even hot egg yolk or anti-dandruff shampoo. These used in various ways will bring up beautiful intermediate colours . The progress to dark grey can be arrested with cold water and preserved for a while with wax, but this is not permanent. There are also proprietary solutions such as Platinol, which is less smelly, but will only achieve the final dark grey colour.
It is worth noting that solder joints and traces of solder which might have been picked up from a soldering block, will develop a slightly different colour, so getting an even effect is a challenge. Once darkened the shine can be restored with a wet and bushy glass brush and the high spots can be brightened with a cloth to create an antiqued look. The final appearance can be enhanced by waxing. Renaissance, a microcrystalline wax is preferred by jewellers, but failing this any posh furniture polish with natural waxes will do the trick.
Below are some leaf brooches made for friends from sheet and wire in ’98. They were coloured by suspending them over ammonium sulphide in a closed box, but they will be looking rather sad by now.
Your comments and add-ons welcome, Dennis
Silver will darken in bleach and strong detergents too, due to the formation of silver oxide. This is best removed by re-polishing, or by gently heating and pickling. By the way, don’t ever wear a silver necklace while floating in the Dead Sea.
As with many things in life, while some people work hard to keep their silver bright, others prefer just the opposite, which takes us to the subject of patination…
Patination can be brought about by sulphur containing compounds such as liver of sulphur, ammonium sulphide and even hot egg yolk or anti-dandruff shampoo. These used in various ways will bring up beautiful intermediate colours . The progress to dark grey can be arrested with cold water and preserved for a while with wax, but this is not permanent. There are also proprietary solutions such as Platinol, which is less smelly, but will only achieve the final dark grey colour.
It is worth noting that solder joints and traces of solder which might have been picked up from a soldering block, will develop a slightly different colour, so getting an even effect is a challenge. Once darkened the shine can be restored with a wet and bushy glass brush and the high spots can be brightened with a cloth to create an antiqued look. The final appearance can be enhanced by waxing. Renaissance, a microcrystalline wax is preferred by jewellers, but failing this any posh furniture polish with natural waxes will do the trick.
Below are some leaf brooches made for friends from sheet and wire in ’98. They were coloured by suspending them over ammonium sulphide in a closed box, but they will be looking rather sad by now.
Your comments and add-ons welcome, Dennis