The disclosed embodiments provide a component for a portable electronic device. The component includes a gasket containing a rigid portion disposed around a bottom of a heat pipe, wherein the rigid portion forms a duct between a fan and an exhaust vent of the electronic device. The gasket also includes a first flexible portion bonded to the rigid portion, wherein the first flexible portion comprises a flap that is open during assembly of the heat pipe in the electronic device and closed over the heat pipe and the rigid portion to seal the duct around the heat pipe after the assembly.