Műtárgyvédelem, 2002 (Magyar Nemzeti Múzeum)
Összefoglalók
THE FOUNTAIN OF FISHING CHILDREN Bronze sculpture from the turning of the century Gábor Séd Speaking about outdoor metal statues and sculptural ornaments, the first thing that comes to the mind is bronze, which has been considered one of the noblest raw materials of this artistic field since the classical times.Formerly when environmental pollution usually meant carbon dioxide coming from heating, alkaline copper carbonates (“grünspan”, verdigris) coated, as corrosion products, the surfaces of bronzes and other objects made of copper-based materials. If it took many years or decades to develop, the process resulted in the development of a so-called noble-patina on the surface, a kind of a film of semiprecious stone. Its most common forms are similar to the azurite Cu,(CO,)2(OH)2 and the malachite Cu2CO,(OH)2 minerals. Environmental pollution of our days causes corrosion not only in cities but, due to air currents, in the natural environment free of industrialisation and urbanisation. Owing to the increased emission of sulphur dioxide, the salts of sulphuric acid dominate. Fountains are a form of outdoor statues with a special function. The surfaces of fountain statues are usually covered thickly by scale, which lends a stone-like appearance to the metal especially where it is in touch with water and where Ca and Mg salts, which cause the hardness of water, precipitate on the surface. The chlorine content of water contributes to the deterioration of the metal, it starts a chain reaction and, along with the development of hydrochloric acid, damages the metal. The developing, originally white, copper chloride appears in a light green colour in an alkaline form. Acidic rains create alkaline copper sulphate from the material of the artefact, which largely increases the surface outwards. The above processes on the surface of the object, in interaction with its raw material, dissolve the surface, make the material porous and finally perforate it. In result of processes that significantly increase the surface, the waste of constructions carried by wind gets adhered to the surface. The pollutants consisting mainly of lime dust turn into calcium sulphate in the effect of sulphuric acidic rains. This crystallization leads to the appearance of a substantial expansion force in the pores of the material, in the fissures and the details of the ornaments. At fountains, a preventive protection can be carried out, beside modern protective layers in the case of bronze statues, with the establishment of a water purifying and turning equipment. The water purifying equipment, which can be attached to the water supply system of the fountain, filters the running water nearly to the purity of distilled water. This water gets into the fountain and this already purified water is rotated by the equipment. A simple time switch can be installed in the system, which secures water supply in the needed interval ÜVEG, EZÜST, ÓNAMALGÁM Velencei típusú tükrök helyreállítása Kovács Petronella, Mester Éva A tükrök előállításának fejlődése szorosan összefügg a táblaüveggyártás fejlődésével. Míg ennek technológiája az évszázadok során folyamatosan fejlődött, a tükörképző fémborítás anyaga és felhordásának technikája nem sokat változott. A 16. századtól a 20. század elejéig, az ezüstborítású tükör általánossá válásáig, a tükrök ónamalgám bevonattal készültek. Fényvisszaverő rétegük ónban gazdag szilárd-, és higanyban gazdag folyadékfázisból áll, mely az ón/higany amalgám kristályok 176
