A method of determining bonding agent coverage in a joint between a first substrate (10) and a second substrate (12), including: dispersing a marker material (18) throughout a bonding agent (16); melting the bonding agent (16) but not the marker material; solidifying the melted bonding agent (16) to form an actual bond (24) in a joint between the first substrate (10) and the second substrate (12); detecting the marker material (18) in the joint through at least one of the substrates to ascertain an actual bond (24); and comparing the actual bond (24) to an expected bond (28) for the joint to determine the bonding agent coverage.