Evaluation of Glues and Glued Products

The author discusses the probable causes of deterioration of glue joints. Types of external mechanical stresses are discussed and types of internal mechanical stresses are also described. These latter stresses are largely the result of moisture pickup by the wood. The author indicates how internal mechanical stresses may be reduced by proper joint construction. The author also discusses the effect of microorganisms and heat and cold on the glueline. Certain types of glues exhibit thermoplastic characteristics when heated. Chemical degradation of the glueline is also discussed. This type of degradation is accelerated with temperature in service. Data on actual temperatures in service are limited. The author points out the difficulty in developing new accelerated tests for the durability of glue joints. There are several factors which must be considered in durability tests. The first is type of specimen. The type and size of construction and the species in the test specimen will, to a considerable degree, determine the type of test condition to be used, particularly in cyclic exposures. The preparation of test specimens is another factor to be considered in durability tests.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member