Mineral Preservatives in the Wood of Stradivari and Guarneri

Following the futile efforts of generations to reach the high standard of excellence achieved by the luthiers in Cremona, Italy, by variations of design and plate tuning, current interest is being focused on differences in material properties. The long-standing question whether the wood of Stradivari and Guarneri were treated with wood preservative materials could be answered only by the examination of wood specimens from the precious antique instruments. In a recent communication (Nature, 2006), we reported about the degradation of the wood polymers in instruments of Stradivari and Guarneri, which could be explained only by chemical manipulations, possibly by preservatives. The aim of the current work was to identify the minerals from the small samples of the maple wood which were available to us from the antique instruments. The ashes of wood from one violin and one cello by Stradivari, two violins by Guarneri, one viola by H. Jay, one violin by Gand-Bernardel were analyzed and compared with a variety of commercial tone woods. The methods of analysis were the following: back-scattered electron imaging, X-ray fluorescence maps for individual elements, wave-length dispersive spectroscopy, energy dispersive X-ray spectroscopy and quantitative microprobe analysis. All four Cremonese instruments showed the unmistakable signs of chemical treatments in the form of chemicals which are not present in natural woods, such as BaSO4, CaF2, borate, and ZrSiO4. In addition to these, there were also changes in the common wood minerals. Statistical evaluation of 12 minerals by discriminant analysis revealed: a. a difference among all four Cremona instruments, b. the difference of the Cremonese instruments from the French and English antiques, and c. only the Cremonese instruments differed from all commercial woods. These findings may provide the answer why all attempts to recreate the Stradivarius from natural wood have failed. There are many obvious implications with regard to how the green tone wood should be treated, which chould lead to changes in the practice of violin-making. This research should inspire others to analyze more antique violins for their chemical contents

A simulation study of the Japanese bō

A study on various aspects of the Japanese bo including the most effective way to hold a bo to strike an object, the region along the length of the bo to impact an object, and the best method of resisting an impact were studied with the aid of finite element analysis (FEA). The results offer a very interesting scientific insight into the Japanese bo, which is very useful for improving the techniques of using the bo to one’s advantage, and improving the design of the Japanese bo

Physical and mechanical properties and fire, decay, and termite resistance of treated oriented strandboard

This study evaluated the effects of a number of chemicals on the physical and mechanical properties and fire, decay, and termite resistance of oriented strandboard (OSB) panels. Disodium octaborate tetrahydrate (DOT), boric acid (BA), melamine phosphate (NIP), and a BA/DOT mixture were sprayed onto the furnish at varying concentrations. The panels were tested for thickness swell, water absorption, modulus of rupture, modulus of elasticity, and internal bond strength according to the procedures defined by ASTM D 1037. All treated panels, except those treated with BA/DOT, were found to comply with CSA 0437 requirements for mechanical properties at a 2 percent concentration level. However, thickness swell and water absorption values were higher compared to CSA 0437 standard values. Laboratory decay tests showed that treated OSB specimens were well protected from both a brown-rot fungus (Fomitopsis palustris) and a white-rot fungus (Trametes versicolor). Weight losses in MP-treated OSB specimens were higher than those in boron-treated specimens. However, increased NIP content caused a decrease in weight loss. In termite tests, BA and DOT were more effective than NIP against Coptotermes formosanus. Contrary to decay test results, OSB specimens containing higher NIP concentrations showed lower resistance against termite attack. In a limited series of cone calorimeter tests, treatments did not substantially improve the fire performance of OSB. Of the treatments studied, the highest retentions of BA and BA/DOT provided some improvement in fire performance. DOT also provided some improvement but it was not commensurate with the amount of chemical added

Effect of various tire retardants on surface roughness of plywood

In this study the surface roughness of plywood treated with various fire retardants was investigated. Commercially manufactured veneer of Akaba wood (Tetraberlinia bifoliolata) was treated with borax, boric acid, monoammonium phosphate and diammonium phosphate, then experimental plywood panels were made from these veneer sheets. A stylus method was employed to evaluate the surface characteristics of the samples. Three main roughness parameters, mean arithmetic deviation of profile (R-z), mean peak-to-valley height (R-a), and maximum roughness (R-max) obtained from the surface of plywood were used to evaluate the effect of chemical treatments on the surface characteristics of the specimens. Significant difference was determined (p = 0.05) between surface roughness parameters (R-a, R-z, R-max) for four treatments and two retentions of fire retardants. Samples treated with 3% concentration of borax had the smoothest surface with 11.09 mu m R-a while the roughest surface was found for the samples treated with 6% boric acid having R-a value of 12.44 mu m. Results revealed that the surface quality of the panels reduced with increasing chemical concentration. (c) 2005 Elsevier Ltd. All rights reserved

Correlation Of Adhesive Strength With Service Life Of Paint Applied To Weathered Wood

INTRODUCTION In the absence of adhesion failure, paint on wood exposed outdoors gradually erodes. Degradation of paint by erosion may take a decade or more, depending on the degree of exposure to sunlight and moisture and the thickness and type of paint. While a paint system is eroding, it still protects the wood surface from degradation. Until this erosion process proceeds to the point where the primer begins to show, the paint surface can be renewed readily with an additional topcoat. With timely refinishing, painted wood can last for centuries (Feist & Hon 1984). If, however, the paint--wood interphase fails, the paint film will debond within a short time and the paint will blister, crack, and peel. This failure can result in damage to the wood surface and more difficult and costly refinishing. One cause of interphase failure is a degraded wood surface caused by weathering prior to initial priming with paint (Arnold et al. 1992, Boxall 1977, Bravery & Miller 1980, Desai 1967, Evan