Plaster cast
The plaster cast is a type of molding of three-dimensional objects, for example body parts.
Mask production
Masks are often made with plaster of paris bandages . The face is protected with a fatty cream. Moist plaster of paris bandages are placed on top of this. Caution: nostrils must remain free. The plaster bandage is immersed in cold water for about 2 seconds. This creates heat. The processing time is a few minutes. After drying, the raw mask is removed. The edges are trimmed, the mouth and eyes are cut out. The mask can then be processed further: apply additional material (plaster of paris, for larger quantities supported with a thin wire mesh), paint, glue (fabric, paper, raffia, wool, wood shavings, etc.). Of course, other body parts can also be molded (see next chapter).
In other processes, the plaster mask serves as a mold, for example for GRP masks or for latex masks.
Plaster mask
Latex mask
Plaster cast of the baby bump
The trend of making plaster casts of the baby bump originally comes from the United States and has been popularized in German-speaking countries since 2001 by the Berlin artist Anja von Behr. The work of the New York artist Kiki Smith, whose work Shield showed the circumference of a pregnant woman in the 8th month, was an important model .
During the production of the blank, a so-called abdominal mask, an impression is made of the baby's belly during pregnancy using plaster bandages (ideally Artex fabric). This is usually done four to six weeks before the calculated delivery date. The upper body should be sufficiently greased with petroleum jelly to avoid injuries. Both the negative (from the outside) can be processed and smoothed, or the positive (inside) can be used. The latter results in an absolutely detailed cast of the pregnant upper body.
Orthopedics
A plaster cast gives the orthopedic shoemaker or bandagist an exact three-dimensional template for the production of a foot insert .
A distinction is made between two options:
- Burdened
- The patient steps into a foam, similar to a floral foam at a florist, these negative impressions of his feet are filled with plaster , a positive model is created.
- Unencumbered
- The feet hang freely, be with plaster bandages wrapped after the plaster has set, the negative model a shoe can be removed from the foot like that. This negative form is then treated with a release agent (e.g. swiveling out with undiluted washing-up liquid) and filled with plaster of paris. The positive model obtained in this way now serves as the basis for creating the deposits.
Dentistry
In 1756, Philipp Pfaff published the first textbook on dentistry in German: “Treatises on the teeth of the human body and their diseases”. There he described, among other things, the molding of the jaw with sealing wax, whereby the impression, which was first cast with plaster, served as a model for the manufacture of dentures. In 1840, the Americans L. Gilbert and WH Dwinelle accelerated the setting of the plaster of paris by adding salts and thus transformed it into a suitable impression material, the impression plaster. As a result, plaster of paris was used for functional plaster casts in toothless patients. The hardened impression is broken out piece by piece in the mouth and then reassembled. The plaster cast is then isolated and the model is made. The plaster cast has been replaced by the development of polyether and silicone materials , but is still used in impressions for a dental prosthesis in a so-called Schlotterkamm that has been created by bone loss .
Animal tracks
Animal tracks ( footsteps ), footprints are taken with a plaster cast. A frame made of a cardboard strip is placed around the impression and poured out with liquid plaster . After drying, the plaster cast can be carefully lifted off.
Tire footprint
Earlier in the were Kriminalistik in forensic tire tracks removed in the soil with a plaster cast.
Another measurement procedure is the blue print .
literature
- Babett Forster (Ed.): Valuable. Objects of art mediation: plaster casts, photographs, postcards, slides. VDG, Weimar 2015, ISBN 978-3-89739-829-0 .
Web links
Individual evidence
- ↑ The FAZ called von Behr "the belly mask pioneer". Katja Gelinsky: Belly of Memory. In: Frankfurter Allgemeine Sonntagszeitung. December 12, 2010, No. 49, p. 16.
- ^ Art on the belly: A Berliner makes prints of pregnant women. In: The world. January 11, 2003.
- ^ O. Hofer, E. Reichenbach, T. Spreter von Kreudenstein, E. Wannenmacher: Textbook of clinical dentistry. Johann Ambrosius Barth Verlag, Leipzig 1952, pp. 538-539.
- ^ Heinrich F. Kappert: Dental materials and their processing. 1. Basics and processing. Georg Thieme Verlag, 2005, ISBN 3-13-127148-5 , p. 276. ( limited preview in Google book search)