High temperature plate fin heat exchanger

A plate for a heat exchanger, the plate comprising:

• a first end portion spaced apart from a second end portion;
• a cavity defining a first flow path between the first end portion and the second end portion;
• and
• an outer surface portion defining a second flow path, wherein the plate comprises a single unitary part without a joint between any two portions.

A method of building a heat exchanger comprising:

• creating a core defining internal features including an inner cavity of a completed plate;
• inserting the core within a mold cavity that defines outer surfaces of a completed plate;
• molding the plate to include the outer surfaces defined by the mold cavity an inner surfaces defined by the core, wherein the completed plate defines a first flow path through the inner cavity and an outer surface defining a second flow path;
• and
• assembling at least one completed plate to a first end cap at a first end portion of a completed plate and a second end cap to a second end portion of the completed plate.