No Glue- Other Factors

It is not unknown for the wrong grade of adhesive to be inadvertently used on the production line and if the adhesive container is situated in a pressure pot or similar 

Most adhesives will have a shelf life and invariably if the adhesive is used beyond its nominal life, the viscosity, the cure speed or the final cured properties of that product may well be out of specification. 

Was the adhesive stored correctly or has it been used straight from the fridge and not had time to return to ambient temperature  

The optimum storage conditions for many adhesives is in a refrigerator but if the adhesive is used directly from the fridge at 2 °C to 8 C, not only will the viscosity be higher thus affecting the dispensing characteristics, but also the cure speed also may be prolonged. 

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