This study investigated the effects of heat treatment, following
optional treatment with synthetic, water-based, and alkyd varnishes, on
the pull-off strength of wooden materials sampled from oriental beech
(Fagus orientalis L.), oak (Quercus petraea Liebl.), black poplar
(Populus nigra L.), pine (Pinus sylvestris L.), and fir (Abies
bornmulleriana M.). The test samples were subjected to heat treatment at
temperatures of 165 degrees C and 175 degrees C for periods of 2 and 4 h
with a total of 4 variations. With respect to the wood type, the samples
of beech wood yielded the highest results for pull-off strength, while
fir wood yielded the lowest. With respect to the varnish types, the
highest pull-off strength was found in the samples of synthetic
varnished beech (5,452 with a 37.2\% improvement) at 175 degrees C heat
treatment for 4 h, while the lowest results were obtained in the samples
of fir (0.991 with a 48.5\% decrease) at 175 degrees C heat treatment
for 4 h. In conclusion, heat treatment significantly decreased the
pull-off strength of the woods