There are two primary advantages for using the explosive welding method to produce a heat exchanger. One is that any two dissimilar metals can be used in combination, such as stainless steel on copper. The other is that the pattern of cooling channels that can be configured is versatile almost without limit, meaning that it is possible to produce any pattern of channels inside the heat ecxhangeer body. These channels can be oriented in any direction. The heat exchanger is a solid metal plate, with an internal arrangement of cooling channels designed to maximize heat transfer. The volume of surface area contact to body mass can be designed without limitation of the channeling arrangement.