Lead Oxidisation

NEW LEADED WINDOWS WHAT TO EXPECT

Like any natural lead product exposed to the environment, lead profile will undergo certain 'atmospheric' transformation. This is perfectly natural and it will eventually settle down to take on the traditional 'weathered lead' appearance that is so admired in old churches and the leaded windows of stately houses.
During this process however, especially in the early stages, some people may become concerned at the changes they see occurring.

WHY DO CHANGES OCCUR?

All RegaLead lead profiles are made from refined, almost pure lead and, although this has been alloyed to improve performance, when it is exposed to the atmosphere for the first time it becomes subject to a process called oxidation.
Chemists define the process of oxidation on lead as: "a chemical reaction instigated by the exposure of lead to the atmosphere in which insoluble lead compounds such as lead sulphate (PbSO), lead sulphide (PbS) or lead oxides are formed on the surface. These major reaction products naturally form a compact, non-porousadherent film on the lead's surface which stilifies further reaction between the metal and the atmosphere." Put in more simple terms it means that when lead profile first comes into contact with the atmosphere, the surface gradually oxidizes to form a natural protective film called a patina, and it is this which eventually produces the familiar grey colour.

WHAT CHANGES ARE SEEN?

During the initial stages of patination the lead can appear to take on various colours such as blue, bronze, gold and green. This effect is purely optical and is usually due to the angle of light. The effect is similar to the colours seen when oil is spilled onto a wet road surface. Gradually, however, these colours will fade away to eventually leave the final protective grey patina. There is another side-effect of oxidation which can occasionally give rise to concern. When lead first comes into contact with moisture (rainwater or condensation) it may result in temporary discolouration, spotting and even the appearance of white powdery deposits (basic lead carbonate) which in wet weather can run onto the glass. Again this is perfectly natural and the temporary blemishes will eventually disappear as the patination process continues. The powder can safely be wiped off from time to time until the natural patination process is fully developed.

The time required to complete this cycle will vary depending on the purity of the lead, the location, time of year, environment, weather conditions and airborne impurities.

TREATMENT

There is no need to treat the lead profile as the patination process will occur naturally.

After installation, lead surfaces should be cleaned with warm soapy water and a soft cloth.

Don’t use any abrasive cloths or cleaners, on coated leads.