(Fig.8. Glass tray taped together for glue to set.)
had not run properly so the whole tray was completely secure. After drying the tray was very strong. The tray had tiny glass balls poured into it, these acted like sand would, holding the shape of an object that was put in it (like a bottle) in place without letting it roll, but unlike sand they did not scratch the glass. The walls prevented any balls rolling away and meant that gluing glass inside could be easily transported around the studio without coming apart.
As well as gluing I also did some conservation work while in Erfurt. I worked on my own conservation project of a small panel from Benburg and participated in the early stages of conserving church windows from Dondorf. The Dondorf windows are a working title we gave to glass from a Protestant parish church in the village of Dondorf. It was designed and constructed by Wilhelm Franke in 1912, which is the name given to a designer, maker and company. There were eight large windows in extremely poor condition, only later found out that one light was missing. Their condition was so poor because the church has had new windows fitted and these were simply taken out and left on the floor where they were stood on. Some of the students were trying to piece it back together like a giant version of my earlier jigsaw work. I spent some time helping them with this job in the basement. It was a truly awesome and thankless task because not only was it in a billion little fragments with an unknown amount missing they did not even know what the original was supposed to look like. Parts of the window looked as though
(Fig.9. One of the reassembled Dondorf windows.)
they had once been quite beautiful and it was sad to see it in such disrepair. The university does restoration work on hopeless causes like this for free to teach its students, but I was told by some that this makes it very hard once graduated for freelance conservators to set up any kind of business that charges.
I was also permitted to do a bit of conservation myself. This was on a small section of a window from Martinskirche in Benburg. The panel was 23.5cm wide by 38.5cm high. It was painted with a geometric floral design and was 19th century Victorian. It had no bars, knots or bowing. The internal lead was 6mm flat and the border was 8mm flat. The lead is the original and is as old as the glass. Several of the joins were fractured, there was double leading in one corner and it was in poor condition with an unusual corrosion or fungal condition on the back. The glass used varied from mouth blown red and blue flash, to yellow pot
(Fig.10. Benburg Panel pre-conservation)
metal and a pinky brown tint. The glass was of varying thickness, from 2mm to 3mm. A lot of pieces were missing and there was a lot of breakage. This may be due to wear and tear, perhaps from being badly stored. There were dirt and dust deposits on the front and cement mortar deposits on the back. There was no corrosion to the glass and the paint, which was black trace with a wash, was in good condition without any surface decoration erosion. Previous temporary restoration had taken place and this could be seen in several new solder joints, barely enough to hold it together, and the resining of cracked glass.
The biggest problem I had with this conservation was the cement mortar. Cement mortar is very different from lime mortar which is what you now have to use to put in windows. Slate lime mixed with sand and stone dust creates water permeable lime mortar. It takes a while for it to achieve strength and sealing properties. It can be premixed, and if kept out of contact with air, it doesn't set. Lime is easier to chisel out when repairing old windows and it moves with the building, expanding and contracting.
Cement mortar on the other hand sets under all conditions, even under water. It does damage to old buildings because it is rock hard and water cannot permeate it. It damages the original stone, which contains moisture, by forcing it to become water logged as the moisture has nowhere to travel. It is a very unforgiving material and although the Victorians often used it to put in their windows it should never be used now. In previous studios when we came across glass that had cement mortar attached we had to chisel it off, although this could be hard work and was sometimes to the detriment of the glass. Because of this Strobl insisted that I slowly scratch and chip at the mortar until it turns to powder and using this method to remove all of it, so it would not damage the paint. It took me three days to remove only 10cm by 3.5cm of cement using this method, and although it worked it was extremely labour intensive and not the best use of my very short time there.
Once all the cement was removed I spent time cleaning it with cotton wool and ethanol, scratching at the dirt with a blade. I could not take it apart to clean it as I was to preserve the lead, so even after cleaning it still looked quite dirty, but that might have just been because I was looking at it in the context of the old lead. I took a rubbing on paper using just a pencil, which was tricky, and then taped this down to the table. On top of it I placed a sheet of tracing paper and tried to gauge the sizes of the missing pieces. On closer inspection we noticed that because of the way the glass was shaped at the to the border, it was in fact the bottom right hand corner of a larger design. This we had easily missed the first time because so little of the glass remained. It was decided that instead of creating a full finished window, it should be made obvious that the panel is incomplete and that sections are replaced. I made the design continue a little at the top to give the impression of the continuing pattern.
I was also to paint the replacements in a way that made them obvious. Of the 16 new pieces I cut using stock sheets they had, all must be painted in the usual manner, but
(Fig.11. First layer of paint on glass cut for Benburg panel.)
then diagonal lines were to be drawn across them in stripes. This was a technique they pioneered at Canterbury. The idea is that on close inspection in years to come it will be obvious what pieces are previous restorations. However from the ground as they are such fine lines they shall not be seen. I start by using a very light pinky wash on the back called K-F6371. Once fired I paint in the different designs using black tracing paint where applicable, trying to mirror the original where possible. The one remaining border piece was very stained and grubby looking. Instead of replacing it I tried to paint the rest of the border to match. I was extremely happy
(Fig.12. Completed replacements painted on Benburg Panel.)
with the results which turned out just as I had hoped. Unfortunately I was not in Erfurt long enough to lead the panel back together, something I would very much like to have tried as I have never reused old lead in this fashion. Time constraints sadly meant this was not to be.
On a final note I would like to say that I very much enjoyed my time in Erfurt. I couldn't have wished for more friendly or welcoming colleagues and the city was incredibly beautiful. Professor Strobl was an excellent mentor and took the time to really talk to me and answer my questions, which I always have an excess of, teaching me so much in a very short space of time. It was a wonderful start to my first leg in Germany and I am extremely grateful for the hospitality and warmth shown to me, much needed in a distant land, and which I will remember fondly.