ABSTRACT
Adhesive patched nuts show low installation torque-on values as the compound is soft and mixed during installation. Breakaway torques can be as strong as the breaking point of some soft steels and can be modified to meet customer requirements. Prevailing off-torque of adhesive parts, once the bond is broken, is less than that of plastic patch parts. Some second time hardening occurs, as not all of the encapsulated beads crush and mix the first time, but the values obtainable are happenstance numbers. Reuse of adhesive-coated fastener joints is generally not recommended. Breakaway values, as stated in Tables 9 or 10, could be quite high and in the case of larger sizes (5/s in. M16) make the parts difficult to remove. The time required for adhesive hardening might limit adjustment of the installed fastener. Heat and humidity can cause premature hardening of the adhesive, thereby limiting the shelf life and storage conditions of preapplied adhesive fasteners to inside areas away from furnaces and heaters. Because the adhesive is soft and fills the thread interspaces completely when smeared and mixed by the fasteners, long rundowns are not recommended.
