Laboratoire de conservation, restauration et recherches de Draguignan

Mechanical treatment
In the family of mechanical tools, we have abrasion and we have percussion where we break, cut and remove corrosion products using a scalpel. Abrasive particles (micro beads mainly made of glass or corundum) are propelled towards the elements we wish to remove using pressurised dry air. This wears down and abrades all the foreign components that are not part of the object. It reveals the fossilised surface of the object, which is a lot more homogenous and conserves all traces of use and decoration, as well as the outline of the object. The micro turbine is a tool that is integral to the range of mechanical treatments. As its name suggests it turns and allows the diamond cutter to wear down the surface that we wish to remove step by step, and it allows us to reach the layer that we are interested in.

Treatment using impact
The micro chisel functions a bit differently in the sense that it causes micro impacts like a very small pneumatic drill. The chisel both strikes and turns on itself so that it removes the veneer of corrosion products or other products, shells for example. In this way it allows us to clear the surface that interests us, which appears almost untouched when pieces are removed bit by bit.

Treatment using a scalpel
This is a tool we call a ‘hand tool’ like the others, but in this case it is specifically the hand that guides it, which gives rhythm to the object, and allows
us to cut the remaining corrosion products.

The laser is a new technology that seems promising, but it is still being tested. The laser was used for treating stone in particular, and it would seem that the new equipment allows us to remove the layers of superficial products by using shockwaves. Sometimes old glue turns yellow; this was thought to be irreversible in the past, i.e. you could not unstick an object that had been glued with this adhesive. The laser seems to provide a means to remove this old glue which now looks clumsy, as well as appearing to be useful when stabilising certain metals which have fallen victim to active corrosion, much quicker than the chemical techniques we use today. It is highly advantageous that it is a contactless technique. This is particularly promising in the case of soft materials, for example lead, which sometimes have vestiges of use, traces of writing or decoration ; therefore we can reveal all of these details without damaging them at all, without intervening at all. This could revolutionise our discipline.