i made a duct with Aluminium Foil Adhesive and glue to hot temps

i was doing some tests and i think the problem that the heat dont go to the heatsink and stays in the board.
A copper heatsink will solve the problem, may a copper pad with a large surface area do something.
i   will fit some heatsinks in the back off the board.

Great machine main is at 425mhz plus 1380gh