Transient liquid phase bonding (TLPB) is a joining process that can be implemented for a variety of material systems. It is of particular interest to the aerospace industry for both production and reparation of complex components which have strict requirements for mechanical properties and undergo high service temperatures. The use of TLPB has been successfully demonstrated and is used widely. Researchers have sought to develop models of the isothermal solidification (IS) kinetics, which are a critical component of TLPB, with some success in binary and simplified systems. To date, however, there has not been a robust analytical model which can estimate the TLPB process. Here, differential scanning calorimetry (DSC) is used to quantitatively study the IS kinetics of the Ti64-Cu system with a brazing temperature of 1050 °C (above the Ti64 ß-transus temperature of 980 °C). A half braze joint was subjected to a cyclical heat profile (1050–850 °C) where the liquid fraction of filler metal remaining was determined after each isothermal hold at the brazing temperature by measuring the enthalpy of transformation on each cooling segment. These measurements were subsequently used to estimate the required time at temperature to achieve complete isothermal solidification in a braze joint with a specified gap width. The predictions from the DSC results were validated using optical microscopy and SEM/EDS analysis. Successful full bond joints (FBJ) were produced using TLPB to examine the effects of varying foil thickness on the joint.