Monday, 23 August 2010

Derix Glass Studios - Continued

The next step is to mix the glue. They used a two part silicone solution which was mixed together then put into a vacuum for a few minutes to remove the bubbles. This apparently is the secret ingredient to getting a smooth invisible finish to your lamination. It was a very basic bit of equipment that I would never of thought of and it made the liquid bubble free. The glue was then poured over the area to be laminated. The top piece of glass is stood in the glue where it is supposed to go on one edge and very very slowly lowered down into the silicone so no air is trapped. It is then pressed down on and weights are sometimes put on top. If more than one piece is being glued down at once tape is put across them to make sure they stay at the same level and in the same place together.

(Fig. 26 . Oldenberg project ready for removal of glue.)

The glass, once glued, is sat on an electric matt to speed up drying. It usually takes four hours to cure but with the matt it can be set in one hour. A lot of the work I did while in Derix was cleaning up laminated panels. Once dry excess glue has to be removed. First all the tape and the vinyl is pulled off. A scalpel and a sharp blade are

(Fig.27. Excess glue removed from Oldenberg glass.)

used to score around the edges of the glass to make sure no trace of extra silicone is stuck on. This takes a while. The glass is lathered in white spirit and the edges are gone over with wire wool afterwards. Once it is cleaned in this way it is cleaned again with glass cleaner. The blades must be extremely sharp otherwise the cut lines will look ragged and be visible and this would be a disaster.

For the Oldenberg project, after cleaning I masked the edges and top surfaces with foil and tape so that the bottom could be sandblasted. If the glass had not been taped this way it would have been a nightmare to clean out the sand. Altogether for this project there were three layers of glass, and two layers sandwiching them all together. Top layer was the art glass then a layer of silicone glue sticking it down to tempered glass with foil to laminate it to a final layer of tempered glass. The tempered glass, foil, tempered glass combination is outsourced and done by another company. Tempered glass is very fragile but strong. The edges when knocked or dropped will cause the whole glass to shatter into thousands of pieces, but at the same time hold together. This is important because it means if the ceiling light was to be broken it would not fall down onto everyone's heads.

The final piece of work I did in the glazing department was on Markus Lipertz's St. Andreas Cloister in Cologne. These were a series of windows in different sizes and shapes that would fit inside this church. The stone work was very old and original features needed protecting. Instead of putting the new glass back into the stonework it was to be put in front of it and clear protective glazing would go into the stone. I puttied and cleaned some of these windows and on others I added an extra border of lead sheeting to block out the light and hooks to attach the glass inside the church. All this I will now explain in detail.

The first task I did on this project was to putty and clean the windows that had already been leaded. The way we puttied them was slightly different from how I had puttied in the past. The putty itself was different. It was like leaded light cement but without the black colouring. It came in large plastic pots and some of it was a little watery.

(Fig. 28.Putty taken from bucket brushed into Lipertz project then sawdusted.)

The consistency was more like linseed putty, a little grainy. I think it was subtly different from anything I had used before because it was something they made up themselves, but no-one was able to tell me. I brush puttied the panels, but using a much nicer brush than I had used in the past. Whenever I had done this job before it was always done with a cheap rubbishy brush sometimes even with plastic hairs, or the firm long and flat type you use to polish shoes. In Derix I was given a completely new beautiful brush, very like a large English Stippler and it was quite sad getting it so messy. Another thing that was different was that they used sawdust instead of whiting to soak up the oil.

The process was simple: Firstly, apply putty with brush, making sure it goes under all the lead; Secondly, scrape off excess with a flat edged wooden stick and then press down the lead (usually in my experience this would be done with an oyster knife, however I didn't see a single one used the whole time I was in Germany so I think perhaps it's just not part of the tradition there); Thirdly, cover with sawdust and brush with a normal cleaning brush (as described above) to work the sawdust in so it can soak up oil left from the putty, a rag is also used to do this. The brushing is done quite vigorously to really clean the putty residue off the glass; Fourthly, go around the edges of the lead with a nail to remove the harder to reach excess putty then vacuum the glass to lift off all the sawdust, then re-sawdust any areas that are not quite clean.Once the panels were puttied and cleaned I had one final job to do on them. I had to cut to size and solder on sheet lead to go around the edges of the windows. As I mentioned above the glass is not going back into the stone work but sitting in front of it. Because of this there was a concern that light would seep past the outer edge of the glass and be obvious and unsightly from the floor below.

(Fig. 29. Lipertz project. Sheet lead cut long and laid in place over wooden batons to solder.)

The artist Markus Lipertz did not want this. It was therefore decided that extra lead would be cut and attached onto these outer edges, the sheeting will overlap the stone a little and because of this it will block out all unwanted light.

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