Abstract: In an electroforming method for making metal products having a pattern of openings separated by dykes using a mandrel in an electroplating bath, metal from the bath is deposited on at least two electrically mutually insulated regions. Said regions comprise at least one main pattern for product dykes to be formed, which main pattern is electrically insulated from at least one ancillary pattern for a reinforcement to be formed. In the method according to the invention, first the ancillary pattern is connected to a current source in order to form reinforcement thereon and in order to effect an electrical connection between the ancillary pattern and the main pattern by means of the growing metal. During the continuation of the method, reinforcement is thickened and the product dykes are formed. A strong product having different thicknesses is therefore obtained in one step. A mandrel suitable for use in the method is also described.