The answer as I understand it that the aluminum section is first prepared by plating copper onto its surface with the help of a chemical bath and electric current. Next, a layer of nickel is used to cover the copper coating on the aluminum, and a similar procedure is also done with the copper base plate.
j'offre 38? main propre un midi porte de champeret ou clichy pour le rad seul sans le ventillo 80mm (que tu n'aura aucune difficulter à refourguer pour les 7? de difference )