Research in adhesion performance of permanent elastic joints of galvanized sheets and veneers in course of time

Regulations and practice in designing residential and hotel buildings prescribe the use of steel fire resistant doors, partitions, parapets etc. The improving and decorating of these large galvanized surfaces have been performed by using reactive and finishing lacquers and the technology of veneering by solid epoxide glues has been developed. However, there is a problem as wood and thin galvanized thermounstable sheets achieve opposite behavior in the same conditions: in cold and humid microclimate veneer expands while sheet contracts. The so far researches and unsystematic efforts have been based on high resistant solid glues (epoxide, polyamide etc) and the results were deformations of planes, pre-tension, cracking of veneer and losing of adhesion. This research, however, tries to verify certain hypotheses concerning performance of a new model with high elastic permanent joint and to prove a favourable time development of the joint adhesion during 90 daily treatments. It has been concluded that by this the problem concerning veneering of fire resistant elements of galvanized sheets has been solved in a very simple way. The second stage of research should examine the influence of veneer and permanently elastic thiobondings on inflammability, speed of flame spreading, flame development in test-ovens and increasement of caloric value of the doors treated in this way.