Surface heat flux plays a vital role as an important design parameter in a wide range of engineering systems and subsystems, such as steam/gas turbines, internal combustion engines, and many more. This emphasizes the necessity of fast-response thermal sensors to manage thermal readings that are short-duration, highly unstable, or periodic. Thermal sensors with fast response times are crucial for meeting these demanding requirements. Thin-Film Sensors are commonly used for heat flux measurements and are particularly effective in short-duration test environments. TFSs are preferred because they are simple to fabricate, respond quickly, have good measurement precision, and can be used with test models of different shapes. Depending on certain needs, the substrate’s size and shape may change, but its depth must be sufficient to meet a semi-infinite solid’s presumptions. However, many studies highlight adhesion issues between thin films and substrates. This study presents a robust methodology for fabricating platinum TFS. Platinum TFS is fabricated using Macor as the substrate material, selected for its strong adhesion to platinum. Conductive platinum paste is used to create the sensing thin film, which was meticulously hand-painted with a fine, precision brush, resulting in a film thickness of approximately 10–50 μm. After the film making, annealing is done at 750 °C to relieve thermal stress and stabilize its structure. An oil bath approach is used to calibrate the sensor for determination of their TCR and sensitivity. The sensor annealed at 750 °C exhibited a TCR value of 0.0012/°C.