Wood has ability to pasting, and it distinguishes it from many other types of construction and finishing materials. As a result of pasting the permanent connection turns out and if 50 years ago it was applied as joiner's connection, then today pasting is applied to improve physicomechanical indicators of wood.
Wood is organic material which allows bend, longitudinal expansion, torsion. Even the humidity is capable to change it. Therefore when choosing glue it is necessary to consider that it met all these requirements.
Preparation of glue for wood pasting
Products from tree stick together by means of joiner's (bone or pure skin), all-purpose resin or casein adhesive. At the same time most often use joiner's glue which can be executed in the form of granules, tiles and also in shredded look. Apply it both by production, and at repair of glued products from tree.
For preparation of glue solution the joiner's tiled glue needs to be crushed then to fill in it with water and to leave for 8-12 hours for swelling. It has to cover glue on several centimeters. Then the part of water is drained, and the glue structure boils soft on small fire at constant stirring. To exclude glue burning, it should not be razvarivat directly on fire. Ware with structure can be placed in other capacity in which there is hot water. To define readiness of glue, it is necessary to apply it on board and to check for stickiness.
Technology of pasting of wood
Before repair it is necessary to soften and remove old glue from wooden product. For this purpose put wet rag on it for a short time (about 2 hours) then the softened glue is removed with knife. The glue structure very quickly dries therefore it is necessary to train it in small amount. It is also necessary to remember that it is not necessary to add old glue to new glue structure. Before pasting the product needs to be dried well. Indoor temperature when pasting has to be from 15 to 20 degrees. If it is higher – glue will become too liquid and at compression of parts will be squeezed out from them if below, glue is very dense and will not be able to get into all time of parts. Adherend surfaces have to be plain. In need of their surface it is possible to process plane, file, and then abrasive paper No. 100-140. The appeared dust is removed with brush and wiped with the rag moistened with acetone or water. Glue when drawing on surface has to be warmed up to 50-60 °C. In this case it will better get into time of adherend wood. Thickness of seam of dry glue has to be from 0.1 to 0.15 mm. When pasting the structure is applied on both surfaces at once. If pasting happens along fiber, then the surface is greased with glue of 1 times if end-to-end (faces) – 2 times, at the same time the second adhesive layer is put after partial drying of the first layer (at touch it has to be sticky and be extended in thread). After that the parts prepared for pasting should be connected and clamped in vice, or screw clamp. It is also possible to pull together product with bandage. If glue was used too dense, compression needs to be strengthened. It is necessary for reduction of thickness of adhesive layer. The adherend product has to remain compressed about 3 hours. Plywood is kept by not less than five hours. If further processing is necessary to product, it is maintained within 2 days.