A method and a device for bonding at least two sheets, is disclosed. The sheets may be joined by a groove and are connected to each other at least in one contact area in the sheet surface of the first sheet. The sheets may first be shaped whereby the first sheet may be shaped with at least one hook which forms an angle with the sheet surface and the second sheet may be shaped with at least one groove and one leg. The hook may be accommodated by the groove and the leg may be substantially parallel to the contact area of the first sheet. The shaped sheets are then bonded to each other, whereby the hook is inserted in the groove and the leg is bonded to the contact area.