harpoons and flensing knifes
the collection Smeerenburg: iron tools, semi manufactured and
untreated material from the smithy of a 17th century whaling station at
Smeerenburg, Spitsbergen, Norway
origin: Spitsbergen (Norway)
date: 17th century AD
[each set of two attached figures gives an impression of the
iron artefacts before and after treatment]
During the 17th century the Republiek der Zeven Verenigde ProvinciŽn
(the Republic of Seven United Provinces) (about
1580-1795) occupied a prominent position within the network of international
ecomomic relations. Whaling activities in the area of the archipelago Spitsbergen
comprised an important factor. In the late 16th century the northern arctic
region was explored. By among others Willem Barentsz expeditions were executed
to obtain a more accessable northeastern passage. Dutch whalers have explored
parts of the archipelago for decades to maintain more or less permanent storage
edifices, accomodations and working areas.
In the 1970's and 1980's a few intensive archaeological
expeditions were executed on Amsterdameiland nearby Smeerenburg.
The remains of a settlement were detected and an inventory was made. The
settlement had been in use as a whaling station and was explored from 1614-1660
regularly to prepare the whales caught.
[click on the photo to enlarge the map of the site]
To the settlement belonged houses,
storage buildings and horseshoe shaped try-houses. In two of three occupation
periods remains of forges were encountered. The excavated basic materials,
semimanufactures, completed and repaired tools offer a detailed insight in the
technical skills of a 17th century smith who had to work under spartanly
circumstances. The figures show some examples of objects found on the site:
before and after treatment.
Active and passive conservation
condition before treatment:
The excavated iron objects from Smeerenburg have been stored for
several years under disputable conditions. This stimulated corrosion. The
primary corrosion products of all the Smeerenburg iron contained
chlorides. Chlorides katalyse the corrosion process. Iron chloride is unstable
and in presence of oxigen and water vapour corroded iron will form complexes on
the border of primary corrosion and metal iron visible as brown rust. Besides
rust strong yellow coloured druplets of a solution of iron ions and chlorides
will form. Newly formed corrosion products will disrupt chemically stable
corrosion. Fissures appear and the object starts to desintegrate. As a result of
this proces the original surface and eventually the original form will
disappear. As long as there is a metal core the proces will continue.
Brown coloured rust and dried in yellow droplets were present on virtually
all objects. On some objects the original surface was damaged due to a loss of
To stop the current corrosion proces two measurements are essential: the first
is a form of active conservation and consists of desalination of the iron.
Desalination means removal of the chlorides. Secondly passive conservation is
essential; that is to create good, dry circumstances for storage. After
treatment the iron must be kept at an atmospheric humidity of less 20%.
Before treatment all objects have been photograghed in their
"original" state. Moreover X-ray photo's were made to gain information
when the "original" surface was obscure.
After excavation the objects had been treated with linseed oil to reduce
corrosion This oil now hampers the desalination and must be removed first.
The iron is desalinated by means of immersion. The "bath" consisted of
a solution of sodium hydroxide and sodium sulphite in destilled water. The
solution promotes removal of chlorides from the iron, the iron ions form a
After desalination the objects were allowed to dry and cleaned mechanically
by means of cutting- and grinding equipment. The original surface (as far as
present) is exposed. The X-ray photo's were extremely helpful in this proces.
Fragmented objects have been reconstructed and/or completed. The restoration
adhesive Paraloid B72, and epoxy adhesives as Araldite 2012 were applied.
Finally the iron is impregnated with microcrystalline wax.
Objects that directly or indirectly will be exposed to air (for instance in an
exhibition) have been treated with tannine, before the application of wax.
Tannine will form the stable iron tannate on the iron core. This provides extra
protection against corrosion.
After active treatment the objects are wrapped in acid free paper.
Together with silicagel and atmospheric humidity indicators they are stored in
air tight containers. The containers are placed in a room with climate contol.
Besides conservation research was done on the objects to obtain information
on composition and forging techniques of the iron. By means of metallographic
analysis insight is gained on the technical skills of a 17th century