An often overlooked but vitally important aspect of body jewellery is the surface finish. By surface finish piercers mean how well the jewellery is polished or if there are any coatings. A good surface finish will be smooth, contain no nicks or scratches, have no inclusions and be proven safe. A poor surface finish can irritate the piercing channel and cause a piercing to not heal, grow excess scarring or reject.
The polish of a jewellery is how smooth the surface is. The term “Mirror Polish” is used regularly by piercers and jewellery companies but this is only a marketing term and has no real world value. There are several ways to measure the smoothness of a surface but Ra (Average Roughness) and RMS (Root Mean Square) are the most commonly used. Ra gives a very simple view by measuring the difference in peaks and troughs along the surface and creating a straight line whereas RMS looks creates a broader image by also looking at the width of the peaks and troughs.
Thanks to Rob Hill of Prysm, Des Moines we have data about various jewellery companies surface roughness and when cross referenced with historical data during his piercing career he has put forward that a surface finish of 5-7 μm is required for a piercing to heal with and with minimal scarring. If this all sounds too technical for you then there is always the option of looking closely, as a well polished piece will be obvious to spot.
Nicks and Scratches
It might seem obvious but a lot of people look past a simple scratch as being the cause of their irritated piercing. A nick or scratch can harbour bacteria and cause friction or cuts which can lead to irritated and even infected piercings. A damage free surface will be able to move comfortably through a piercing without causing any irritation.
Inclusions come from the manufacture of the jewellery. If machines and tools are used to work on various different materials then they can embed inclusions. An example of an inclusion would be steel lathe tools leaving traces in a titanium labret. The inclusion might be fine for some people but others can have adverse reactions e.g. Nickel sensitivity or the inclusion could cause the jewellery to be faulty e.g. a steel inclusion causing anodising to fail.
The prevention of inclusions is at the manufacturer stage and our favourite companies all work hard to minimise them but lower quality companies may not. As inclusions aren’t always visible to the naked eye it is recommended to have all Titanium jewellery anodised.
Next weeks blog will continue on surface finish but will look at the world of Coated and Plated Jewellery, both good and bad!