In the use of glue, too much glue will make the macromolecules in the glue crowded together, and there will be no good tension between the macromolecules. At the same time, the water between polymer bodies is not easy to volatilize. This is why "the thicker the adhesive film, the worse the adhesive effect". If the amount of glue is too much, the large amount of glue plays a role of "filling" rather than bonding. The bonding between objects depends not on the adhesive force of the glue, but on the "cohesion" of the glue. If it is not water-soluble, the principle is the same. It is just using other solvents instead of water.