A heatsink is a piece of aluminum that conducts heat very well with many fins so it has high surface area. Steel washers do not perform like a heatsink because steel is a poor conductor of heat and the surface area is low.
We use a thin layer of "thermal compound" that conducts heat well (not super glue) beteen the regulator and the heatsink to fill in the microscopic dents in the surfaces for good heat conduction. Then they are bolted together.
A 7805 has a metal tab that is bolted to a heatsink. A 78L05 is small without a metal tab. Gluing it to a piece of metal does not help cool it much.
We use a thin layer of "thermal compound" that conducts heat well (not super glue) beteen the regulator and the heatsink to fill in the microscopic dents in the surfaces for good heat conduction. Then they are bolted together.
A 7805 has a metal tab that is bolted to a heatsink. A 78L05 is small without a metal tab. Gluing it to a piece of metal does not help cool it much.