The unique attraction of the art of stained glass is based on the tension between the material glass and the ever-changing, the colors to life-inspiring light. The technique and the individual steps involved in the manufacture of stained glass have not really changed since the Middle Ages when they began assembling differently colored and painted pieces of glass in lead rods.
Colored glass windows are made up of three components: the glass as a carrier of color and at the same time wall-forming matter; the lead net as the stability granting framework and support of the linear composition, and the painting, which ultimately modulates the light passing through the glass and serves as a means of representation.
- Pause and stenciling
- Colored glass selection
- Cutting the glasses
- Painting, glass coloring with silver yellow and etching
- Lead coating
- Inserting the windows
In the case of artistically designed colored glass panes, which are to be installed as windows in a building, the first work step is that the artist commissioned with the design goes on-site to familiarize himself with the exact dimensions, the orientation, and the light conditions. The latter is of crucial importance, above all, for the design of the windows. The most important dimensions relate to the size and shape of the window in which the load-bearing framework of the ironworks must be installed, the soldiers, and the depth of the window rebates and grooves.
The colored design of a window on a reduced scale (usually 1: 10), must show how the artist intends to design the finished window: in detail figures and decorative elements are shown, the color distribution and the lead network and the ironwork, the later the different window fields will stick together. The design must be sufficiently precise so that it can be enlarged by squaring or photographically.
Cardboard is the name for the artist’s design in the original size of the window but without colored representation. On the cardboard, the exact lead net, which will connect the pieces of glass with each other, is drawn. Also on the box, the exact positions of the storm bars (transverse iron) and wind rods, as well as the details of the contour drawing and their shadow accompaniment, are given, so that the glasses can be painted correctly in the sequence.
Pause and stenciling
Since the paper has become more widely available, the outline drawing is transferred to solid stencil cardboard with pause and carbon paper. The resulting drawing, the Riss, represents a kind of puzzle whose individual parts are numbered. After cutting the stencil carton, these facilitate the assembly of the stencils on the break.
The cutting apart of the crack, or the preparation of the stencils, is done with the so-called. Double scissors, which removes a narrow strip of paper with its three blades, the width of which corresponds to the core of the later together holding the glasses Bleiruten.
Colored glass selection
The choice of colored glasses is made on the basis of the color values indicating design. The wide range of colors available to the glass cutter allows a faithful implementation of the design.
The medieval glass consisted of a mixture of two parts of beech or fern ash (potash) and one part of sand (silicon), which were fused together at about 1500 degrees C. The glass thus obtained was almost colorless. For the production of glasses of different colors, metal oxides were added to the glass mass. The difference in color is also a consequence of certain impurities present in the glass mass from the outset.
Cutting the glasses
Stencils that are to be cut out of one color are placed on the corresponding colored glass so that as little glass waste as possible is formed. From the glass panels, the individual glass pieces are then cut out around the stencils with the diamond or steel wheel glass cutter. The cut glass piece is removed from the glass sheet either by finger pressure or with a pair of pliers. For particularly complicated shapes with distinct spikes, a small hammer is used to extract, tapping on the side of the glass facing away from the diamond cut.
Painting, glass coloring with silver yellow and etching
The paint, the black solder, consists mainly of oxidized iron or copper powder (hammer blow) and a flux, crushed lead glass, which begins to melt at low temperatures so that the liquefied paint can be inextricably linked to the first softened base glass.
Depending on the technique, vinegar or turpentine oil is added to make the oxides and lead glass into a malus substance. A small number of liquid binders, such as gum arabic, improves the adhesive properties of the black solder.fire
The painted and possibly with silver yellow stained glass pieces are reassembled on the break. On a metal plate, a layer of screened and dried gypsum is applied, on which then the glasses are arranged as evenly as possible so that they do not deform during the firing process.
As in the Middle Ages, the individual glass parts are now given on a wooden base, where they are fixed with nails in their position with the lead rod lying around: a rectangular wooden frame fixed to the workbench holds the lead edges of the edge, which form the bottom and left side Form side of the disk. Place the first piece of glass in the corner and press it down with the weighted lead handle of the lead knife. A suitable lead piece is placed around the glass, cut to size, and fastened with a few nails. Now the adjacent pieces of glass are used according to the same scheme and connected with lead rods until the disc is finished.
Inserting the windows
Since a leaded glass window usually consists of a large number of individual window fields, because dead weight and wind pressure limit the extent of a leaded window, these fields must be fastened on traverses, which in turn must be anchored in the walls.