Stained Glass - Cleaning & Some History

Window cleaners at some point in their career will be asked to clean stained glass windows.

Clone Trooper Stained Glass Window is One of a Kind: For those of you who are building your very own Star Wars cathedral, you will want to check out this Clone Trooper stained glass window for inspiration. I’m sure that all of the churches and cathedrals throughout the Empire have stained glass like this, portraying troopers, Vader and the Emperor. Maybe a Hoth attack scene. How else are you going to keep the rabble in their place? That would be a pretty amazing sight. I would worship there for sure. Aiden T' also made a sweet Star Trek emblem stained glass window. They are both some amazingly awesome work. I hang my head now to pray for more amazing and geeky stained glass.

Spring cleaning for 16,000 glass mosaics in Berlin's historic church hit by WWII air-raids: Industrial climbers clean window elements of the Kaiser Wilhelm Memorial Church in Berlin. To restore the original luminance of the windows of the Kaiser Wilhelm Memorial Church in Berlin, more than 16,000 glass mosaics are being washed with hot water high-pressure cleaners. Click pictures to enlarge.

It’s like a jigsaw puzzle. People either love them or hate them, I loved jigsaws as a kid which is probably why I ended up in stained glass windows.

Jonathon Hunt: A stained glass jigsaw obsession - Coloured glass has been used and created by humans since ancient times, predominantly used in glass vessels, jewellery and decorative works reaching as far back as the Egyptian and Roman empires. However, the most recognised use of stained glass throughout the ages has been in the production of stained glass windows, commonly found in churches, cathedrals and places of worship throughout the modern world.

Evidence of stained glass windows can be found as early as the 7th century in England, the earliest of which dates from 675 AD when Benedict Biscop imported French labour to glaze the windows of a monastery he was building in Monkwearmouth. Much of the technical and artistic development behind the stained glass window movement in North Western Europe arose during the Middle-Ages, with the desire to glorify Gods, Saints and Generals in lavishly decorated cathedrals to educate a largely illiterate populace on religious teachings and glorious victories. Not to mention the need to keep congregations sheltered from the elements.

Shelter was and is a key design consideration for stained glass window makers. They must be able to withstand the wind and rain but also, especially in larger works, must support their own considerable weight of glass and lead. Today the use of coloured glass can be found almost everywhere, in contemporary design, architecture, wine glasses and lampshades. Stained glass has a number of aliases and production techniques, functioning as an umbrella term for a myriad of glass practices, depending on the place and time of manufacturing. Glass panels can be painted with enamels or reactively stained using metal salts and minerals and then fired in a kiln to preserve the coloured translucent effect.

Stained glass is a generic term. Leaded lights and stained glass comes under the same banner, but staining itself is a particular yellow stain which you use. It is not like enamel – which is how you paint on glass – but staining. The yellow stain actually reacts with the glass and literally stains it. Enamels and paints will need to be touched up and replaced but the staining will remain. Again, that is just one type but purists will say that is the genuine form of stained glass. The processes of making and restoring a stained glass window: essentially you take the window out of the frame, either a wooden frame or, with churches and stone buildings, the windows are set and glazed within the stone, so you would have to chip away the mortar. Once the window is removed we can then board or temporarily glaze the window space and we take the window back to the workshop to take a rubbing.

Once the rubbing is done I remove the glass and recycle the old lead. From the rubbing, which is your basic template, just like a jigsaw puzzle, you place the panes of glass in the right order and map the trace lines of the heart, which will be your template for putting the window back together again. Before piecing the work back together you obviously have to clean and replace any dirty or damaged glass, which is a usual occurrence when it comes to restoration, along with wear and tear on the leads and the cement. Stained glass needs to be carefully cleaned using ionized water and a shammy leather. There is a difference between leaded lights and stained glass. Stained glass is where the colours are actually painted on and then fired in the oven, which is a very delicate process. When cleaning you need to keep as many of the original painted features as possible.

Once the glass is cleaned it is placed in a jig, with a border lead which is generally 12mm thick. Then you place and attach the glass onto your template with a lead ‘came’ which is what holds the lead together, along with soldering joins on the glass and lead. The soldering flux then needs to be washed off, which can stain the lead. Some people use tallow which is a mixture of rendered animal fat and resin. Personally I use a plumber’s flux which is non toxic and doesn’t stain. Next comes the mucky part: the cementing of the piece which, depending on the complications of the pattern takes a long time. The cement itself is based on the dust of old cement, black vegetable die, linseed oil and white spirit. Whiting (calcium carbonate powder) is then used to dry the cement, which is left for a day and then you have a finished panel which you refit.

Alot of people say “Oh, stained glass that’s really arty etc” but then I say stained glass is really like a jigsaw puzzle and then they get it. People either love them or hate them, I loved jigsaws as a kid which is probably why I ended up in stained glass windows. This work has been going on for a thousand years if not longer. The old methods and techniques really haven’t changed. It is just like a craft such as carpentry or stone masonry. Obviously now there are machines like sand blasters that can speed processes up such as shaping glass which would have taken months or years of forming with pliers before such technology.