7.2.2 ‘No Cure’

Having checked for the presence of adhesive (‘No Glue’), the next step is to check whether the adhesive has fully cured. This should be a relatively straightforward analysis, as uncured adhesive will be in a liquid or gel state, may be tacky to the touch or show signs of discolouration (which, in the case of 2C adhesives, may indicate insufficient mixing). This step should be relatively easy to check when the components are separated.

7.2.3 ‘No adhesion’

The third (and probably the most common) failure mode is when the adhesive does not adhere properly. This may be due to several factors, including surface contamination, oxide layers, incompatible substrates, low surface energy substrates and/or excess moisture. The general cause of this failure is a mismatch of adhesive and substrate or lack of proper surface preparation (see Section 2 for further discussion of the basics of bonding and adhesion and Section 4 for surface preparation).