Basic frame sections shall be 1-7/8” extruded aluminum alloy 6063. Corner of main frame shall be coped to receive its mating extrusion and joined mechanically by two sheet metal screws. All assembly screw heads and corner joints shall be factory-sealed. Glazing material shall be set in a bed of wet A.A.M.A. approved glazing compound. Glazing beads of extruded 1/2” x 1/2” x .062” shall be set in glazing compound and exposed sealant tooled to provide smooth minimum radiused seam. Main frame, glazing bead, interior and exterior glazing muntins shall be formed in an infinite combination of bends to meet job requirements. All muntin crossovers, and end brackets shall be of nylon with homogeneous color of either white or bronze to closely match the color of frame and muntins.