Tony Jarvis
Photos by the author

If you are new to electronic construction or model railway construction, ‘heat sink’ may be a confusing term. It is a small device that enables heat from a soldering iron to be absorbed or diverted away from sensitive components such as LEDs, chips and semiconductor devices.

In my early days of electronics ,they were not really needed as ‘bottles’ (valves) were the norm, but as design advanced and miniaturization took over, a move into semiconductor devices began. These started as PNP or NPN transistors with three output wires. Now we have gone even further with the move into chips, which plug into holders very much in the way that valves plugged into valve-holders, but capable of performing much more complex tasks. If you are into DCC then this format is very familiar to you. For many years now components have been surface-mounted, i.e. soldered to the surface of the PCB. There is still a wide range of through-mounted components such as LEDs, and these are the kind we generally use. Semiconductors can be damaged by too much heat from soldering, which is where a heat sink is useful.

Are they easily made? The answer is probably, particularly if you have basic soldering skills. They can be made easily from items from the scrap box and, in my case, hair grips. These I acquired by the packet (100) from Amazon and, apart from being used here, I also use ones that resemble large alligator grips as a temporary holder for parts, as I spot solder long joints, solebars etc. They are cheap enough to throw away once they get corroded. If you have a friendly hairdresser that also may be a source. The other parts are some scrap brass to act as dissipating paddles. These can be seen in the second photograph. If you have some copper then so much better as they will dissipate heat far more quickly.

Cut the brass to the size you want and solder them to the clip. To avoid the potentially sharp edges, cut some sleeving to go around each edge of the paddle. The items can be seen protecting a 5mm red LED, whilst making up a small breadboard test circuit. Note that some hair clips sold by suppliers are made from aluminium. These have the advantage that they can't be accidentally soldered to the workpiece but, obviously, are unsuitable here for the same reason.