The disclosure is directed to a method for co-molding. A first element (1060, 1260, 560, 760) has a top surface (1041, 1061, 741, 761), an edge (1043, 1062, 1162, 1243, 1262, 1362, 143, 743, 762, 862), and a protuberance (1035, 1235, 735) with a base (1037, 737) extending down from the top surface (1041, 1061, 741, 761). A second element (1065, 765) has an edge (1043, 1062, 1162, 1243, 1262, 1362, 143, 743, 762, 862), an upper surface (1041, 741), and a lower surface (1064, 764).The mold (1100, 1300, 300, 600, 700) includes a first mold portion (1010, 1110, 1310, 310, 610, 710) defining a co-molding upper surface (1041, 741), and a second mold portion (1020, 1120, 1320, 320, 620, 720) defining a co-molding mold (1100, 1300, 300, 600, 700) cavity. The first element (1060, 1260, 560, 760) is placed into the second mold portion (1020, 1120, 1320, 320, 620, 720) with the protuberance (1035, 1235, 735) base (1037, 737) in contact with the second mold portion (1020, 1120, 1320, 320, 620, 720). The second element (1065, 765) is placed on top (210) of the first element (1060, 1260, 560, 760). The mold (1100, 1300, 300, 600, 700) is closed, thereby producing the second element (1065, 765) as a chamber. Fluid under pressure introduced into the chamber forces the second element (1065, 765) to conform to the shape (1150, 750) of the mold (1100, 1300, 300, 600, 700), thereby to affix the first element (1060, 1260, 560, 760) to the second element (1065, 765). Energy is applied to the mold (1100, 1300, 300, 600, 700) to co-mold (1100, 1300, 300, 600, 700) the elements together.