Two-part adhesive composition that undergoes a visual change when cured

The present disclosure provides a method for bonding parts, comprising the following steps (a) Providing a two-component adhesive composition precursor, comprising a first part (A) comprising at least one epoxy curing agent and preferably at least one first dye; a second part (B) comprising at least one second dye different from the at least one first dye and at least one epoxy resin; (b) Mixing part (A) and part (B) of the two-component adhesive composition precursor so as to obtain an adhesive composition; (c) Applying the adhesive composition onto a first part; (d) Applying a second part onto the adhesive composition applied to the first part; and then performing a first curing step at a first temperature, wherein the adhesive composition undergoes a first colour change; or (e) Performing a first curing step at a first temperature, wherein the adhesive composition undergoes a first colour change, and then applying a second part onto the adhesive composition applied to the first part; (f) Perform a second curing step at a second temperature higher than the first temperature, thereby fully curing the adhesive composition so as to obtain a structural adhesive bond between the first and second parts, wherein the adhesive composition undergoes a second colour change.