PROCESS FOR THE REPATINATION OF AREAS RESTORED BY SURFACE PASSIVATION OF OLD BRONZE AND BRASS PIECES

摘要

The invention relates to a process for the repatination of areas restored by surface passivation of old bronze and brass pieces, consisting in using an ethyl alcohol or isopropyl alcohol-based dispersion containing stibium pentasulphide, ammonium sulphide and thio-urea, at the following gravimetric ratio: alcohol/Sb2S5/(NH4)2S/S=C(NH2)2 : 10/8/1/1, said alcoholic dispersion being applied on the cleaned surfaces by brushing or rubbing with a tampon imbibed therewith, at the ambient temperature, for 10...20 min, while covering the whole surface to be chromatically reintegrated by repatination, the surface moistened with the alcoholic dispersion being then left to rest for 8...12 h, further on it is brushed or slightly rubbed again with imbibed tampons for 5...10 min, finally the non-adhering suspension excess being washed with a thin jet of alcohol and the so treated piece is wiped with tampons or wipes and is preserved in exsiccators, ovens with temperature control at 35°C, at the most, or drying chambers.