Bruk av kalk och sand ur ett hantverkligt perspektiv

Sammanfattning: Sweden has a thousand-year history of burning (calcinating) and slaking (hydrating) limestone to produce a binder for mortar and stucco. We can assume that the conditions for manufacturing such binders have varied from one part of the country to another. The reason for such an assumption is that limestone is a collective term for a variety of stone types that consist primarily of the mineral calcite but whose properties and composition vary from place to place. In some places, the local limestone has been affected by heat and pressure to produce crystalline limestone. Lime must be burned and slaked in different ways depending on its composition and attributes. From a historical perspective, it is likely that knowledge of the techniques for manufacturing lime binders developed through successive experimentation as kiln types and slaking methods were adapted to the local limestone. Other factors that may have influenced the development of lime binder manufacturing are the availability of fuel and the demand for binder product. For the purposes of this research project, we examine the production of lime binder from the geological layers of limestone in Kinnekulle and the nearby communities, where we may assume the limestone found in buildings has been quarried locally. These include Gillstad Church, Väla Church, and Källstorp Manor Chapel. So far the project has included: - Survey of Kinnekulle limestone usage - Development of lime kilns for burning of lime - Development of methods and tools for slaking lime Besides providing data for study and analysis, Gillstad Church, Väla Church, and Källstorp Manor Chapel have been used as case studies in the use of locally manufactured lime. Additional studies are planned for other areas with locally occurring limestone resources. At the request of the National Property Board, and as part of the research project, we have burnt and slaked lime for the restoration of stucco work at Läckö Castle. This commission has benefited the project by increasing the volume of burned and slaked lime, which has illuminated some of the choices that may have traditionally influenced the choice of limestone, kiln type, kiln temperature, and slaking method.