MACROMOLECULAR SUBSTANCES USED FOR

CONSERVATION AND RESTORATION OF HORN SCOOP

Expert restorer engineer Ligia Otilia Teodor

Research and Conservation - Restoration of Cultural Heritage Centre Iasi

The piece of work this paper is referred to is a scoop of horn (Nr.Inv. 17 403) discovered

by archaeologist Mrs.Maria Diaconescu from The Botosani County Museum, on Vorniceni

archaeological site, in the point “Ibăneasa Bridge”, campaign 2008, in hole AB.

Vorniceni settlement dated to the Eneolithic Cucuteni type AB is 0.40-0.90 cm shallow

and the Cucuteni layer, rich in archaeological material where the piece has been discovered is a

brown-ash soil [1] .

According to the report presented by the research team responsible for archaeological

excavations at Vorniceni after 2001 campaign [2] , the study of arheozoological material regarding

wild mammals in the area revealed the predominant presence of stag, Cervus elaphus and the

identification of remains belonging to the deer, Capreolus capreolus. This, together with shape

analysis allows us to conclude that the part we refer to is a fragment from the horns base

belonging to one of these two species, namely the contact between the horn and skull. The object

is part of the mechanical processed bone material found on site, its careful polishing indicating

the use for leaking fluids (Figures 1a and 1b). You can only make assumptions on how its use -

for capture of springs, for libations or within religious sacrifices.

The shape particularity required the preservation and restoration of the piece for its

exposure in the museum to illustrate social and spiritual life of the community of Vorniceni

Eneolithic site.

After washing the object in running water to remove the soil deposits from the site it

followed an immersion in distilled water for several hours and then chemical treatment to

remove limescale. This operation was performed in 20% citric acid bath for several minutes also

helped by a mechanical intervention with the scalpel.Then we proceeded to an intensive

neutralization with usual and then distilled water till neutral pH.

After slow drying at room temperature for several days, the piece fragments were

preserved by repeated brushing with PARALOID B72 10% solution in acetone and

polymerization took place at ambient temperature. It was aimed to avoiding the emergence of a

glossy film with oversight of the solution concentration.

PARALOID B72 - an acrylic resin copolymer with 30% methacrylate and 70%

ethylmetacrylat [3] - is one of the most stable thermoplastic resins used in conservation and has

special qualities: it is transparent, reversible, has very good mechanical strength and is stable to

the environment conditions that means resistant to oxidation, light, moderate hydrolysis and heat.

These characteristics derive from its properties [4] :

- glass-transition temperature Tg 40 ° C

- Tukon Hardness 10-11 (KHN)

- SWARDROCKER Hardness 80

- graphite Hardness H

- solubility 9.3

-viscosity (at 25 ° C sol. 40%) - in acetone 200

- in toluene 590

Paraloid B72 moderate hardness makes it suitable for a wide variety of basic materials

conservation and hence for bone and horn objects. There is a direct relationship between

mechanical properties, resistance to pressure, resistance to flow and scratches and molecular

weight or degree of polymerization of a linear polymer. Therefore Paraloid B72 provides

appropriate properties for the successful conservation of the pieces of bone and horn, unlike high

molecular weight resins.

Paraloid B72 solutions are prepared using different solvents: xylene, toluene or acetone.

In our case we preferred solution in acetone 10% due to solvent accessibility, but also because of

its properties previously checked on other objects of archaeological horn.

Experiments using Paraloid B72 in various solvents have shown that acetone offers

solution with quick release of solvent required for successful implementation of an acrylic

consolidator and is also the least toxic of the solvents commonly used. Solvents with slower

evaporation, such as toluene or xylene, give solutions with long action time and slow drying of

the polymer layer, prolonging unjustified the conservation process [5].

Paraloid B72 has achieved widespread recognition as a stable and reliable consolidator

and who is important in any conservation laboratory, its preparing and properly using resolving

all the general requirements for restoration and conservation.

After conservation was follow the assembly stage of bone fragments. This was achieved

with a macromolecular substance well known in restoration laboratories - ARALDITE 2020

epoxy resin. Fragments were fixed with scotch tape applied across joints on one side and then

resin was infiltrated (prepared in 3:1 ratio resin: hardener) in the gap on the opposite side of the

strip. Polymerization was initiated by heating with an infrared lamp.

The next step was filling in missing portions of the object to a level considered normal.

No advanced additions were made as restoration principles require us to stop where the

assumption begins. Total recovery of form after the analogy was not possible because they were

not available.

The additions made to object to highlight the original form were also made with epoxy

resin type ARALDITE 2020 ratio of 1: 1 resin: hardener, with the supplement of plaster moldano

for a higher viscosity and thus a more easy application on curvature. The resin was preheated to

IR lamp for initiating polymerization and increase viscosity and then was applied in missing

areas on a wax support (at large addition) or scotch tape support (at small additions) in stages,

gradually within a few days (Figures 2a and 2b). Polymerized resin with high hardness was

mechanically polished using an electric motor with different grit abrasive stones, matting due to

this operations contributing to the aesthetic integration of fillings (Figures 3a and 3b).

For fragments assembling and for additions we used ARALDITE 2020 resin due to its

superior characteristics: contraction is small, less than 3%, has very good mechanical and

chemical resistance, has high adhesion to any material support, including bone and horn. It is

also colorless and successfully resistant to aging.

Using the two macromolecular substances - Paraloid B72 acrylic resin and ARALDITE

2020 epoxy resin for restoration of the scoop of horn was due to the characteristics of these

polymers that meet the basic principles followed in our work, namely: they are waterproof and

protect well against moisture, are resistant to chemical influences of air pollutants, are stable to

light and does not interact with objects, are resistant to organisms attack and are chemically

stable, are transparent and colorless, non-toxic, are resistant to aging successfully and are

reversible.

These qualities make them superior to other resins and so their use was the best choice to

ensure the proper protection for this horn object over a very long time, to storage and exposure in

environmental conditions set by the rules of conservation. Respecting these rules is necessary

because in other temperature and humidity conditions, the protective action becomes insufficient

and that may damage the piece, knowing that the objects of organic materials are more sensitive

and more difficult to preserved and stored than inorganic materials.

Notes

1. Şadurschi P., Diaconescu M. - Vorniceni, Vorniceni village, Botosani County, Point: Bridge

Ibăneasa, site code: 39845.02, in The Chronicle of Archaeological Researches in Romania,

campaign 2001, pag.336-337

2. Ungureanu A. - Study of arheozoologic material derived from the eneolithic settlement from

Vorniceni - Bridge Ibăneasa in The Chronicle of Archaeological Researches in Romania-

campaign 2001, pag.337

3. Horie CV – Materials for Conservation; Organic consolidants, adhesives and coatings,

Butterworths & Co. Ltd., 1987

4. Feller RL – Thermoplastic polymers currently in use as protective coatings and potential

directions for further research, ICCM Bulletin 10, 1984, 5-18

5. Koob St.P. – The use of Paraloid B72 as an adhesive: its application for archaelogical

ceramics and other materials, Studies in Conservation 31, 1986, 7-14

Illustrations

1a 1b

Fig. 1a and 1b - Horn scoop- before restoration

2a 2b

Fig. 2a and 2b- Horn scoop - during restoration (partial completion)

3a 3b

Fig. 3a and 3b - Horn scoop - after restoration