Procedures to Find Out Which Glue Is Stronger

Tensile Strength

• The tensile strength of glue refers to how much weight or pressure it can withstand from vertical force before it stops holding. To test it, the bottom portion of the test material needs to be anchored firmly so it won't move. Then, vertical pressure needs to be applied to the top layer of material. The pressure should be applied with a device capable of measuring the pressure exerted, similar to a fish weigh-scale to determine which glue has the most tensile strength.

Shear Strength

• Glue should also be tested for its shear strength. This is the type of strength needed in a single lap joint. This means that one piece of material overlaps another and that the two are held together by glue. To test the shear strength of glue, the top and bottom part of a lapped joint need to be pulled horizontally away from each other. The more force required to separate the joint in this motion, the greater the shear strength of the glue.

Double Cantilever Beam Test

• The double cantilever beam test is used by the professional agencies and researchers that test the strengths of various adhesives. First, two equal pieces of material are bonded together completely. The glue is allowed to dry and cure completely, and then a crack is created along the glue line to allow force to be exerted on the bond. The two pieces of wood, metal, plastic or other material are pulled apart from each other while equipment monitors the reaction of the glue as various stresses are placed on the material.

Woodworking Tests

• Glues used in woodworking are primarily used to create a connection between the different types of joints used in the craft. Almost any type of joint that can be connected using nails or screws might also be created or reinforced using glue. Therefore, tests to find the strongest glue should be performed on wood glues across all the different types of joints used in woodworking. The glue needs to be totally cured, and then measured force is applied to see which glue breaks most easily on each given type of joint.