7 CONCLUSIONS

BUTVAR GAVE MORE IMPROVEMENT IN strength and stiffness than Acryloid B72. This agrees with the results of Schniewind and Kronkright (1984). There is some evidence that Butvar B98 gives better improvement in strength than Butvar B90. Solvent retention in films of Acryloid B72 suggests that it has limited potential as a consolidant, but it has the advantage of producing solutions of lower viscosity than Butvar.

The data suggest that polar solvents may be better than non-polar ones. However, if penetration is a problem, non-polar solvents that produce lower viscosity (and may have other advantages since wood is more permeable to non-polar than to polar solvents) would be indicated.

Concentration should be as high as possible, consistent with achieving adequate penetration. Lowering the concentration in difficult cases would increase penetration, but of course the retention per unit of volume so treated would then be lower.

Using very slow drying led to lower strength values of specimens treated with Butvar but had no statistically significant effect on those treated with Acryloid.