Available in oval profile: 3mm, 3.5mm, 4.5mm, 6mm, 9mm, 12mm, 18mm, 22mm
Natural Oxidisation of Lead
Decra Led self-adhesive lead strip is designed for applying on interior or exterior flat glass surfaces to create a leaded window effect without cutting glass or soldering joints.
Decra Led self-adhesive lead strip is ideally suitable for use in insulated glass manufacture, complying with EN 1279, the manufacture of furniture panels or for in-situ application to existing windows.
Decra Led is manufactured from refined lead ingots, in such a manner that the metallic composition of product is guaranteed a minimum of 99% lead content. However, as with all lead products i.e. lead sheet, pipes, flashings, etc., it is subject to an oxidation (weathering) process and will form a naturally protective patina when exposed to the atmosphere.
This patina briefly is a layer of highly insoluble lead salts, which gradually form on the lead surface to eventually give the familiar (or traditional) grey lead appearance. Good examples are church windows and the old leaded lights where the lead has oxidised and formed its natural patina.
During the initial stages of the oxidation process, lead can display various colours including blue, bronze and even green. This effect is perhaps best described as optical, as these colours are mainly determined by the angle of the light and will fade away.
When lead comes into contact with moisture: rain-water, condensation etc., at an early stage, discolouration, spotting and white powdery deposits (usually basic lead carbonate) can form and may ‘run-off’. The degree to which all these effects occur is governed by the environmental conditions, but with longer term weathering, the lead will take on its familiar appearance. Investigations have shown that the patina formation follows the route: lead, lead oxide, basic lead carbonate, normal lead sulphite, and normal lead sulphate.
The ‘run off’ stage occurs when non-adherent basic lead carbonate is formed, usually through contact with moisture. Each of the other stages in patina formation is adherent, highly insoluble lead salt and in practice, as these salts develop with weathering, they stifle the basic lead carbonate release. The final patina being approximately 30% normal lead sulphite, 60% normal lead sulphate and 10% normal lead carbonate.
However, this can vary dependent upon location, time and airborne impurities.
We recommend that any lead carbonate deposits are wiped off immediately using a soft cloth and warm water; the longer lead carbonate is left untouched the more difficult it will become to be removed.