Modification of wood surface for the purpose of a better gluing

Prior to gluing with PVA beechwood and spruce surfaces have been modified by means of water solution of ammonium-hydroxide. Preceeding the modification, the joints' surfaces had been sawn and planed. Upon processing and modification of the surfaces, the average height of uneven areas R., has been measured. Wetting on sawn, planed and modified joints' surfaces has been tested. The tests were made on relations between wetting and strength of a glued joint, wetting and penetration of glue, penetration of glue and strength of a glued joint, wetting and evenness of strength along the joint.