A mold for casting and retaining electrophoresis gel strips, the mold comprising: an array of elongated lane cavities, each having a length greater than a width, each lane cavity having a top end, a bottom end, and two or more sides disposed along the length of the lane cavities, the lane cavities oriented parallel to each other; a first solid material and a second solid material disposed along the sides of the lane cavities, the first solid material separating the lane cavities from each other and the second solid material separating the lane cavities from the space outside the mold, wherein the second solid material comprises two window plates (120,130); and a plurality of windows (122, 132) formed in the two window plates (120, 130), wherein two windows (122, 132) are associated with each lane cavity and are disposed on opposite sides of the lane cavity orthogonal to the length of the lane cavities, each window (122, 132) running lengthwise along the lane cavity and penetrating the window plates (120, 130), wherein the windows (122, 132) are aligned to, but are not as wide as, the lane cavities and the windows (122, 132) do not run the entire length of the lane cavities, thereby forming a passage from the lane cavity through the window plates (120, 130) to an adjacent lane cavity or the space outside the mold, wherein (i) the first solid material comprises a comb, the comb comprising a plurality of teeth (111, 112), and the lane cavities comprise the spaces between the teeth (111, 112), and (ii) the window plates (120, 130) are bonded to opposite sides of the comb, each window plate (120, 130) comprising at least one of the plurality of windows (122, 132). an array of elongated lane cavities, each having a length greater than a width, each lane cavity having a top end, a bottom end, and two or more sides disposed along the length of the lane cavities, the lane cavities oriented parallel to each other; a first solid material and a second solid material disposed along the sides of the lane cavities, the first solid material separating the lane cavities from each other and the second solid material separating the lane cavities from the space outside the mold, wherein the second solid material comprises two window plates (120,130); and a plurality of windows (122, 132) formed in the two window plates (120, 130), wherein two windows (122, 132) are associated with each lane cavity and are disposed on opposite sides of the lane cavity orthogonal to the length of the lane cavities, each window (122, 132) running lengthwise along the lane cavity and penetrating the window plates (120, 130), wherein the windows (122, 132) are aligned to, but are not as wide as, the lane cavities and the windows (122, 132) do not run the entire length of the lane cavities, thereby forming a passage from the lane cavity through the window plates (120, 130) to an adjacent lane cavity or the space outside the mold, wherein (i) the first solid material comprises a comb, the comb comprising a plurality of teeth (111, 112), and the lane cavities comprise the spaces between the teeth (111, 112), and (ii) the window plates (120, 130) are bonded to opposite sides of the comb, each window plate (120, 130) comprising at least one of the plurality of windows (122, 132). (i) the first solid material comprises a comb, the comb comprising a plurality of teeth (111, 112), and the lane cavities comprise the spaces between the teeth (111, 112), and (ii) the window plates (120, 130) are bonded to opposite sides of the comb, each window plate (120, 130) comprising at least one of the plurality of windows (122, 132).