crystal sculptures

Nordic glassart

Mats Jonasson having done a drawing I make a plaster model. This is an exact replica of the finished piece. At this stage, I decide on the background - what is to surround the piece. It is often more difficult to achieve perfect harmony between the motif and its surroundings and I frequently spend longer working on the surroundings than on the animal itself.

It is the chiselled, crystal-like texture that I want to bring out. An eagle on a cliff works well but an animal moving through out the forest is more difficult. The background to the animal motif must help to create the mood.

The next step is to engrave the body on the plaster model. Then I varnish the model and make a positive cast of it also in plaster. This cast, which is the right way round, is the model for the final iron mould. On the final plaster model, I enhance the fine details of the motif before passing it to the iron foundry. In the foundry, a sand core is produced and then the iron mould is cast. We now have a raw mould. On the raw mould the work continues. I use diamond drills, revolving files and ultrasonic tools to clarify the details of the motif and to polish the parts requiring a glossy finish. When I am satisfied with the mould, it is passed to the glass workshop where the molten crystal is cast in it.

We start by heating the iron mould so that the difference in temperature between it and the molten crystal is not too severe. A "gatherer" takes molten glass from the post using a long iron.

Gathering the melt can leave imperfections in the crystal. Bubbles may develop and these have to be removed. We use a crystal of a special type which the Swedish Glass Research Institute has helped us to develop. This is the most costly crystal but it is especially well suited to casting and pressing. A large piece of this crystal has greater refraction and is smoother and more brilliant. It treats the light in a special way.

After casting, the glass is annealed in a lehr for 15-10 hours. If it is cooled too quickly, it will crack. After annealing there is a first quality inspection. Glass with imperfections is thrown out. It is important to get rid of defective pieces before the laborious post-production work is started. the first stage of this is sandblasting. If I want a particular area to remain glossy - the stripes on a zebra, for example, I mask them with silicon which prevents the sharp sand from getting at them. We work with different grades of cutting sand at various velocities. After sandblasting, the motifs are polished and some are then sandblasted again using coarser sand at a higher velocity to increase the whiteness.

Any unevenness of the background and foot of the pieces is then ground smooth. First the pieces is ground on a coarse diamond wheel and then on a finer wheel before being polished in two stages. The second "putty" polishing uses tin oxide which gives a highly polished surface. The final stage consists of engraving in order to achieve the minutest details of coat, plumage and eye that are so vital to the impression made by the finished piece.

Beside the effects obtained from making use of relief, I also have access to the graphic artist's full range of possibilities. The graphic artist can use every nuance from black to white, while I have a scale from polished gloss to coarse matt. The craft process means that each relief is different. Many hands and eyes have contributed to the finished object". Mats Jonasson