•Lead–tin alloyed artifacts are protected using a lead dodecanoate coating.•Electrochemical and immersion deposition are used.•SEM–EDS and XRD measurements confirm the formation of a lead dodecanoate layer.•EIS measurements show a clear corrosion inhibition using the immersion technique. In order to understand the corrosive and morphological characteristics of lead dodecanoate protective coatings on real samples, three pipe organ samples were studied using optical microscopy (OM), scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). The corrosion products and elemental composition of the top layer of the different pipe organ samples were investigated. The results indicate that the three pipe organ samples are made of an alloy composed mainly of lead and tin. After immersion and the deposition of the protective coating, only lead and no tin is detected, which indicates the formation of a thick coating containing lead dodecanoate complexes.