Bronze

Patina should not be understood as damaging the material. It is rather a sign of credible aging and profiting from change. Bronze is not a material which is not used up, it is just used.

For our fittings, we use a copper-tin alloy with 92% copper and 8% tin, which is called CuSn8, or material no. 2.1030. This composition is characterised by outstanding resistance to corrosion, high strength and it is very hard. Its resistance to wear makes it suitable for heavily stressed products which are used every day.

The bronze fittings in the 7615 finish are first polished and then pretreated using a process especially developed by FSB.

Immersion in a bath for metals containing copper imitates the material’s natural aging process. With this pre-aging, we create a typical bronze patina, which is just as good as that produced naturally. The final waxing in the factory, protects it from external influences which would lead to discolouration of untreated surfaces. On request, pre-aging with a dark patination is possible as version 7615.

Protection from corrosion

If you require the patina appearance to the bronze from the initial receipt of the product, we can varnish our bronze door handles. As this treatment falsifies the material’s typical character, we would like to advise against it. Varnished bronze fittings also lose their gloss finish as soon as the varnish is damaged and the intercrystalline corrosion starts – please see the corresponding notes about brass.

Surface hygiene

Owing to the increasing occurrence or antibiotic-resistant germs, FSB’s bronze takes on a new significance owing to its bactericide effect. Critical studies in the USA and in Great Britain show that bacteria on copper alloy surfaces are 99.9% killed off after two hours at the latest. This group of bacteria includes the Methicillin-resistant Staphylococcus aureus (MRSA), one of the most virulent and dangerous germs known. When the prescribed hygienic measures are carried out at the same time, it was confirmed that contamination was prevented by more than 99%. Owing to this fact this characteristic of the copper alloy used by FSB, called CuSn8 (UNS designation C52100) has been officially taken up by the EPA (Environmental Protection Agency) into US building regulations, US registration number 82012-2. FSB bronze fittings also carry the European copper quality seal “Cu+ Antimicrobial Copper” (for more information, see www.antimicrobialcopper.com)