This new placement had two purposes : improving my skills in the conservation and restoration of copper allied
archaeological objects (mechanical cleaning, stabilisation, protection) and a first contact with osseous industry (improving old restorations, appearance for study and exhibition, gluing and
filling of frags). In both cases, making of an appropriate storage was needed.
If I am feeling more confident in the way to approach the startigraphy of the corrosion products and so the
treatment of metallic objects, it was very interesting to work on a material I had not experienced before : a bâton percé (Pierced rod) and two small engraved pieces. Everything went well and I
was very pleased to use the knowledge and drawing skills learned during the courses of Ms Christensen.
I am now looking for my next placement but before important things will happen !
Bâton percé from a famous French site during restoration.
Par aliptina
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It's been three weeks that I arrived at the Archäologischer Dienst des
Kantons Bern for a two-month placement in the Conservation of waterlogged organic
archaeological materials. This kind of materials are difficult to conserve as they are very fragile and subjected to the development of micro-organisms. A way to treat them is freeze-drying. if
they are very degraded, the use of PEG-consolidation will help to support their inner structure.
I started working on atmopsheric
freeze-drying which is a kind of freeze-drying ("lyophilisation") without vacuum. The Conservation Lab has a simple household freezer in which
frozen objects are put in plastic air-tight boxes. Each box contains a fan and a sorbent (Silica gel) which purpose is to adsorb the humidity. The water content of the frozen object
sublimes from ice to vapour indeed. As a result, the objects dry slowly ; I weighted them weakly to follow the process. It is important to avoid the presence of liquid water as it is the
liquid water which is the most responsible in the degradation of the objects.
Having still no information on who invented the apparatus used
in Berne, I also have trouble finding information and articles (after the 1980s) dealing with this particular subject... Luckily, several persons I contacted are helping me, provinding
information and articles I could not get.
I am treating six archaeological waterlogged piece of wood this way and even the freeze-drying is not finished yet, it
seems to give good results. I will also treat that way a small fragment of rope when its cleaning will be finished. These objects are 2 500 BCE years old and they were found in the lake
of the Sutz-Lattrigen site. To help me to identify the direction in which the rope was twisted ("S" or "Z" ?), I tried an X-ray of this frag, all alone ..a good day's work !
the rope during cleaning.
Par aliptina
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