A method of producing A vacuum insulated glazing (VIG) unit, including providing a supporting structure and a solid pre-form of port soldering material provided with an opening, the supporting structure resting on the outer surface of the first pane of the VIG unit and extending over the opening of the evacuation hole, evacuating the void through the evacuation hole; and heating the port soldering material to a condition where it flows and merges across the evacuation hole while the supporting structure substantially maintain its position; and subsequently cooling the port soldering material to a solid condition so as to provide a gastight port seal forming a continuous body across the evacuation hole and preventing passage of gas to the void through the evacuation hole, and so that the port seal bonds to the outer surface of the first pane in a pattern that encloses the evacuation hole.