Stained Glass Restoration & Repair Projects
Most decorative glass can be 'fixed' in the event of an accident, old age or vandalism. Bear in mind a repair is never an invisible mend and a restoration entails picking the old lead away from the glass and releading, as faithfully as possible replacing any damaged or missing glass.
Firstly the decorative glass panel must be assessed in terms of construction, materials and design. Any damage, wear and tear must be considered, for example a single cracked piece of glass in an otherwise sound leaded window can normally be replaced in situ. Where several pieces and/or lead is damaged the panel will need to be removed for repair and the frame temporarily glazed or boarded. With any other major work like soldering or resealing the panel needs to be removed for the work to be completed flat one my workbench.
Components of a Stained Glass Window
There are many types, textures and colours of glass manufactured for the 'flat' glass used in leaded glass windows and panels. Older methods created crown glass, cylinder glass (usually referred to as 'antique' glass), or drawn glass .Modern glass is usually machine drawn with specific textures or clear float glass to name but a few. I can show you many hundreds of different samples at my workshop. This glass can be further decorated with painted detail which requires firing in my kiln to make permanent. It can also be etched or even fused with other glasses or metals for a particular finish.
After the glass has been cut to shape (and there can be many pieces in a panel depending on design) the glass is joined together like a jigsaw using 'H' section lead strips known as cames (old English for lengths). This is then soldered together at the intersections. Finally the completed panel is sealed with an oil based compound that stiffens and weatherproofs the finished piece.
Types of Damage
- Damage to glass
- Damage to lead
- Damage to frames
Although glass is a beautiful non biodegradable substance which in its simplest form is grains of sand melted together, it can also be fragile and dangerous and care must be taken with all types of glass, from simple drinking glasses to window glass. However, accidents and vandalism can occur and cause anything from a minor crack to total destruction. In most cases a stained glass window can be repaired or replaced.
Lead is a soft metal aptly suited to stained glass due to its durability and ease of bending around the various shapes in a stained glass window. It is very resilient to extreme conditions of weather and has been used in stained glass for many centuries. Over a period of time, though, lead will decay and deteriorate, the sealant will dry up and drop out and the soldered joints will eventually split and come apart weakening the window. This deterioration happens over a long period, typically anything between 80 and 200 years depending on the location in a building and the conditions it is exposed to.
Lead can also be prematurely damaged by impact, poor cleaning practises and unsuitable locations. A common form of damage that I see are panels damaged in caustic soda baths by door strippers and the like. If you need to 'dip' a door or any other type of frame containing stained glass it is advisable to remove the glass panel before dipping. The caustic tank will remove the sealant in the leaded panel and pull the joints apart leaving a rattling, fragile panel, liable to collapse at any moment. In most cases lead can be replaced either partially or the whole panel can be unpicked and releaded. Leaded panels can also be partially or totally resealed using the appropriate compound. This cannot normally be done in situ but flat on my work bench.
All types of frames from doors, windows, decorative screens will eventually deteriorate. Wood will dry out and crack or suffer damp and rot, metal will rust and corrode and stonework will crumble. Decorative glass can be removed, repaired if need be, resized or resited.
Techniques of Repair
- Multiple cracks
- Bowed windows
- Safety and security
Replacing a damaged piece of glass in a leaded window is known as a 'stop' (presumably from 'stopping up' a hole). For the odd replacement pieces this can usually be done in situ. This is a repair and not an invisible mend.
Where the repair is more extensive than the odd stop the panel must be removed for adequate repairs. Often the lead borders will have deteriorated and must be replaced. In this scenario the panel can be effectively resoldered and resealed where needed.
Occasionally, due to the design or cleaning habits, a window will bow or bulge. This can happen when a large panel comes adrift from its steel supports. The panel must be removed to remedy this. The bowing can be rectified in one of two ways. Firstly all the solder joints around the bulge can be cut through on both sides of the panel and this usually makes the panel sag into a flat position where it can be resoldered. Sometimes the lead has stretched over a long period around the bulge and in this case must be releaded. To flatten the panel would make it too big for the frame.
Often when frames need to be replaced people wish to upgrade to double glazing for all the benefits it provides. This does not mean the existing decorative glass must be discarded. The original glass can be put inside the double glazed unit, effectively making a triple glazed unit. Many of my new windows are encapsulated and feature in doors, bay windows, decorative staircase windows etc.
Steel bars are frequently used to support large stained glass panels. The bars are fixed into the frame and attached to the window with copper ties soldered into the window. Similarly many panels are supported with a sheet of safety glass on one side, usually the outside, to protect the decorative glass and make the building more secure.
If you have any queries regarding a repair or restoration project please feel free to contact me.