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The resistance of painting materials and consolidants against wood-destroying insects
1997 - IRG/WP 97-10239
Natural and synthetic adhesives, varnishes, painting materials and consolidants were used in investigations of bioresistance against newly hatched larvae and beetles of Hylotrupes bajulus (L.). Animal glues, casein, drying oils and natural resins such as dammar resin and shellac, were not resistant to attack by these larvae. Similarly, semi- and all-synthetic polymers tested including hydroxypropylcellulose, acrylate and methacrylate compounds, are also subject to attack by newly hatched larvae of the House Longhorn Beetle. In contrast, addition of inorganic pigments provides a significant improvement in bioresistance. This effect is influenced by the thickness and the hardness of the paintlayer. The test with beetles of Hylotrupes bajulus show that the restoration materials which are not resistant against an attack by newly hatched larvae are preferred for the egg depositions by the females.
W Unger, H Fritsche, A Unger


Conservation of wooden cultural property
1994 - IRG/WP 94-30038
A survey of the conservation of wooden archtitectual monuments, art objects and archaeological finds is presented. Each of the three areas has typical conservation problems which reqire the use of selected wood preservatives and consolidation agents. Furthermore specific protection and consolidation methods are necessary. A precise damage diagnosis with non-destructive testing methods is the first step in a careful conservation work.
A Unger, W Unger


Reinfestation of consolidated ancient wood by insects
1998 - IRG/WP 98-10290
Wooden artifacts are often attacked by wood-destroying insects. Therefore conservators have to stabilize numerous objects from such attack. Initially we studied the resistance of painting materials and consolidants on unaffected recent wood against wood-destroying insects (IRG/WP 97-10239). Further, we wanted an answer to the question: Are artifacts, formerly destroyed by wood-borers, reinfested by insects after consolidation. Tests with newly hatched larvae of Hylotrupes bajulus L. showed that there are four different levels of biostability. Only two products - Araldit DY 026 (an epoxy resin) and Lignol AS/AW-K (a polymeth acrylic resin) - provided full protection from reinfestation by wood-destroying insects. Other products such as Paraloid B72 (a copolymer of ethyl methacrylate and methyl acrylate), Plexigum P28 (an iso-polybutyl methacrylate) and shellac (a natural resin with different hydroxycarbon acids) were only partially resistant to reinfestation by insects. The newly hatched larvae penetrated the impregnated layers of wood and reached the resin-free areas. There the insects could survive and develop.
W Unger, A Unger, U Schiessl


On the resistance of consolidated ancient wood against Serpula lacrymans (Wulfen: Fr.) Schroeter
2000 - IRG/WP 00-10348
Structural timbers and other wood objects of cultural value in historical buildings and museums are often attacked by wood-destroying fungi. The aim of conservators is to preserve such damaged timbers and prevent further biodeterioration by impregnation with consolidants. There is little knowledge of the resistance of consolidated timber and art objects to a new attack by wood-destroying fungi. Brown-rotted wood consolidated with acrylic resins, PVA (poly(vinyl acetate)), epoxy resins, shellac, linseed oil, animal glue and a beeswax/paraffin mixture were tested against the brown-rot fungus, Serpula lacrymans. Specimens impregnated with linseed oil and the epoxy resins Araldit BY and Araldit DY did not show noticable mass loss. This was attributed to a high mass gain and even distribution of the consolidants. In contrast, specimens prepared with the acrylic resins Plexigum P-28 and Paraloid B-72 showed approximately 25% mass loss at a mass gain up to 40% because of uneven distribution in the wood. Decreases in mass loss were not proportional to increasing polymer loadings.
W Unger, A Unger, U Schiessl


In-situ experimental treatment and consolidation of degraded timber elements from a XIX century building
2012 - IRG/WP 12-10767
This paper presents the in situ experimental conservation work performed on three timber structural elements from a XIX century building: two floor beams and one roof beam. The palace was built in 1877 in the centre of Lisbon initially with residential purposes. It has four floors, with timber structural horizontal elements, stairs and roof beams (generally of Pinus sylvestris L.). The exterior walls are made of irregular stone masonry bedded on mortar, rendered and painted.
D F Henriques, J de Brito, L Nunes


Cultural heritage – research into innovative solutions and methods for historic wood conservation
2016 - IRG/WP 16-10874
Nowadays, interdisciplinary knowledge, tools and techniques are increasingly used to protect and conserve monuments representing our cultural heritage. This is of great importance especially in case of conservation and restoration of wooden historic artefacts which, as a result of physical, chemical and biological corrosion, have lost their technical, aesthetic and decorative properties. If those processes are not consciously stopped by appropriate conservation works, with the elapse of time they will start to threaten the existence of valuable relics leading to their irreversible destruction. Our generation is responsible for evolving modern, improved techniques and methods ensuring adequate, professional protection for historic artefacts. What is necessary to achieve this goal is close and smooth cooperation between conservators and museum workers, strongly supported by specialised knowledge of scientists representing diverse research disciplines, including biology, microbiology, chemistry, and physics. The aim of the new “Cultural heritage – research into innovative solutions and methods for historic wood conservation” project, supported by the Polish Ministry of Science and Higher Education ( “Dziedzictwo kulturowe – poszukiwanie nowoczesnych środków i metod konserwacji drewna zabytkowego”, No. 2bH 15 0037 83), is to develop new materials and techniques for conservation of wooden artefacts. Many different types of wood are planned to be studied, including dry wood (e.g. sculptures, paintings on wooden panels as well as various wooden constructions: churches, cottages, sheds, etc.) and wet wood (archaeological wood), individually selected for research in accordance to the level of wood degradation. The main idea behind the innovative solutions is based on technology using organosilicon compounds, particularly polysiloxanes and silsesquioxanes, and nanocellulose. Taking into consideration unique opportunities offered by the mentioned substances, it is highly probable that a new method for strength restoration of destroyed wood will be developed, which will therefore enable wooden historic objects to keep their shape and spatial form. Successful realisation of the project’s assumptions will open new horizons in research on conservation and preservation of wooden cultural heritage.
M Broda, B Mazela