DIY Heatsinking PCBs
It is a very simple process that [CNLohr] uses to keep his small RGB LED projects from overheating. It starts by using a readily available silicone thermal sheet as the substrate by applying it to copper foil. He then applies a toner-transfer circuit pattern to the copper by running the pair through a modified laminator a few times. He makes note that you have to apply the plastic backing side of the silicone sheet to the copper foil to prevent the laminator from chewing it up.