We liquefied wood using ethylene glycol and sulphuric(VI) acid. We prepared adhesive mixtures with different proportions of liquefied wood (LW) and urea-formaldehyde (UF) adhesive, and measured the time to start gelling. Using differential scanning calorimetry and rheometer we monitored the process of curing of the selected adhesive mixtures. To confirm the results we passed the test of shear strength of adhesive joints made from previously studied adhesive mixtures. The results show in detail at which temperature gelling starts for each of adhesive mixtures and processes that occur in adhesive mixtures at higher temperatures. The mixtures containing 30 % and 40 % LW, reach the minimum gelling times. The adhesive mixtures start gelling in the temperature range between 95 °C and 135 °C, UF adhesive reacted with the LW components at temperatures between 135 °C and 190 °C. The maximum shear strength reached the adhesive bond made with an adhesive mixture of 10 % LW and 90 % UF adhesive.