Modifiche

[[File:Swan-SelfFiller-SF2-Inscr.jpg|left|thumb|Example of discoloration of a [[Swan]] in ebonite]]

[[File:Swan-SelfFiller-SF2-Inscr.jpg|left|thumb|Example of discoloration of a [[Swan]] in ebonite]]

The material, however, suffers from high mechanical fragility, which makes the ebonite pens not very resistant to shocks and falls, in this case the chemical neutrality proves a defect as it makes it almost impossible to glue pieces of ebonite together in a resistant manner.<ref>see [http://forum.fountainpen.it/viewtopic.php?f=12&t=9228#p115300 this discussion].</ref> Furthermore, with exposure to light, humidity and heat, the sulphur present in the material tends to oxidise, and to emerge on the surface, colouring it with a sort of dark brown opaque film that removes the lustre of the original polish. This patina is an indication of the age of a pen, and even if today there are products that can reverse the process and bring the material back to its original shine, the opportunity for such an operation is questioned by those who do not consider it respectful of the state of the pen.<ref>see [http://forum.fountainpen.it/viewtopic.php?f=12&t=2134 this discussion].

The material, however, suffers from high mechanical fragility, which makes the ebonite pens not very resistant to shocks and falls, in this case the chemical neutrality proves a defect as it makes it almost impossible to glue pieces of ebonite together in a resistant manner.<ref>see [http://forum.fountainpen.it/viewtopic.php?f=12&t=9228#p115300 this discussion].</ref> Furthermore, with exposure to light, humidity and heat, the sulphur present in the material tends to oxidise, and to emerge on the surface, colouring it with a sort of dark brown opaque film that removes the lustre of the original polish. This patina is an indication of the age of a pen, and even if today there are products that can reverse the process and bring the material back to its original shine, the opportunity for such an operation is questioned by those who do not consider it respectful of the state of the pen.<ref>see [http://forum.fountainpen.it/viewtopic.php?f=12&t=2134 this discussion].</ref>

In addition to mechanical fragility, the other fundamental defect of ebonite, at least from the point of view of fountain pen manufacturers, is the substantial impossibility of colouring. For this reason, for a long time, the two ways of enriching the aesthetic aspect of pens were chiselling, to which ebonite lends itself with relative ease, and coating with machined metal skeletons. In the first case we have what is called in jargon ''Black Chased Hard Rubber'' ([[BCHR]]), in the second case the countless variations of the [[overlay|coatings]].

In addition to mechanical fragility, the other fundamental defect of ebonite, at least from the point of view of fountain pen manufacturers, is the substantial impossibility of colouring. For this reason, for a long time, the two ways of enriching the aesthetic aspect of pens were chiselling, to which ebonite lends itself with relative ease, and coating with machined metal skeletons. In the first case we have what is called in jargon ''Black Chased Hard Rubber'' ([[BCHR]]), in the second case the countless variations of the [[overlay|coatings]].