The mechanism of sticking and bonding is based on the interaction of two key factors: adhesion and cohesion, which we explain briefly below.
The two forces of glueing
The figure shows a close-up view of the glued joint.
The marked forces are divided into adhesive forces and cohesive forces.
The adhesive force is the force which holds together the atoms or molecules of different bodies (in our example wood and glue).
Cohesive forces are forces which hold together the atoms or molecules of the same body. In our case, this is the cohesion of the glue particles among themselves.
You cannot really influence the cohesive force itself significantly; it depends on the type of glue and how it was made. Of course you should always observe the correct blending and not exceed the use-by date.
What you can influence is the accuracy of fit of the parts to be joined and the resulting distance between the glued surfaces.
If the glued joint is "wider" than 0.2 mm, the forces in the joint are significantly reduced.
For the best result, the wood surfaces should be glued quickly after creating the joint. If you wait too long, the exactly fitting jointing surface may warp slightly due to varying humidity, and in the case of oily woods such as teak, oil may leak, preventing a clean contact surface.
Adhesion you can influence directly, e.g. by:
Making sure the jointing surfaces are clean and free of grease. The glue cannot stick to a surface that is tainted by greasy or oily substances. To avoid this, it is recommended that you wipe the surfaces to be glued with acetone or alcohol.
Another crucial factor is the application of the glue, which must be thin and even. If the glue is not applied evenly, the bonding forces between the wood and the glue are lacking at some points, which reduces the bonding strength of the entire glued joint.
A wide range of special glues
We offer a broad range of products for various application areas from traditional reversible animal glues, e.g. hide glue to polyvinyl acetate glue (common casein glue), e.g. Titebond Original and waterproof foaming polyurethane glue, e.g. Titebond PU glue till two-component glue.
You will find a wide variety of glues in our DICTUM assortment.