The Natural Oxidation of Leaded Glass


Oxidation starting to occur

The Oxidation Of Lead

Please note that Oxidation will always occur with all options of our Lead Strip. Some lead options are coated leads so there will be less oxidation but they may still oxidise around the edges.

Oxidation is a natural process which affects the appearance of lead, when exposed to the different environmental conditions. These conditions – rain, snow, condensation or any weather cycles will determine the degree of severity of the oxidation of the lead and the time scale over which it will occur. Oxidation is far more likely to occur during winter conditions, with the weather attacking the shiny new surface of the lead strip. The natural colour of lead is a matt grey, so it is normal and inevitable that discolouration will occur to the lead over time.

Oxidation is common knowledge to workers in lead but it is not always familiar with the average householder. Questions sometimes arise about oxidation, the most common question being

” How long will it take my lead to oxidise and look like the house next door?”


Lead before cleaning

The answer cannot be given truthfully by anyone and only the weather conditions can determine this. During the oxidation process it is not uncommon for different colours to appear visible on the lead including bronze, blue or even gold. Once this has happened, it is a sign that the lead strip is forming its own protective barrier.

Cleaning of the glass with warm water, washing-up liquid or a mild glass cleaner will ensure that the lead is kept clean and natural oxidation can take place. The time of year will have an affect on how the lead will change but by no means should there be any concern about the appearance as this natural process will always take place. All lead products are susceptible to this weathering process known as oxidation. This is a natural process that forms a patina which effectively protects the lead from the elements.

These two images help show the effects of lead oxidation. The above image shows a leaded glass panel that was installed a year before the photo was taken and this lead was originally pre-aged as our ‘Option 4’ Aged & Soldered. You can clearly see the salty residue and a ‘blotching of the lead. The below picture is the same panel a few minutes later once we had given the lead a quick rub down with a damp cloth and a little bit of mild glass cleaner.


Lead after cleaning

The patina is made up of insoluble lead salts that give the appearance of a traditional grey lead. Look at the image here to see how the lead may look with the effects of oxidation. The patina is made up of normal lead sulphite, normal lead sulphate and normal lead carbonate.

During the initial stages of oxidation the lead can display many and varied colours. The colours that you will see are partly determined by the angle of view but can include white, copper and even green along with powdery deposits. This happens as the lead comes into contact with moisture and is basic lead carbonate.

Customers should be aware that the changing appearance of the lead will settle down and that any action to remove the patina will result in the process starting over again. There is however, no way of saying how long oxidation will take. This basic lead carbonate can run off onto the glass under some circumstances and should be cleaned to avoid the likelihood of any staining.

If you want to reduce the risk of your lead Oxidising, you may want to consider one of our coated leads to reduce the chances of oxidation occurring. It may still oxidise as it is reliant on the environment of the glass and the lead composition.