Whilst undertaking my
internship in the Metals Conservation studio at the
National Maritime Museum, Greenwich, part of my duties involve regular visits to the stores. On a routine inspection of one of the sections, the discovery of these interesting objects quickly caught my attention. A pair of weighted brass and leather
diving boots, with brass buckles and copper rivets is not something that one comes across every day.
Manufactured by famous London diving company
Siebe Gorman in the mid-19
th century, these boots would have been used for underwater diving on a soft and loose bottomed sea bed such as sand or silt.
The boots were showing signs of active corrosion products of a bright green soft waxy deposit predominantly around the areas where the copper rivets attach to the leather. This is caused by the reaction between the free fatty acids found in the leather with the copper, which forms a waxy metal salt, most commonly known in conservation as a metal soap. The brass was also covered in a green corrosion product, although this was a harder product, more firmly attached to the metal. The leather was dirty, very waxy and rigid and brittle in areas and due to its weight, the leather had collapsed and ‘set’ itself into a slumped form.
Various methods of treatment were decided on to remove the corrosion products, clean, reshape and support the slumped leather suitable for re-storage. Delicate mechanical removal of the waxy deposits was undertaken, taking care not to damage the brown coloured copper oxide layer beneath. Whilst working under a 20 x microscope mechanical removal using a scalpel was used to remove the harder corrosion products from the brass components. A temporary custom built ‘tent’ was used to house the boots for humidification to soften the leather to enable re-shaping and support.
Conservation work on the diving boots is still underway. I am continuing to stabilise the corrosion and will shortly start constructing inner supports for the leather.
Siebe Gorman Diving Boots before conservation treatment