A method for making a downhole electrical feedthrough package where the feedthrough package may include a metal shell forming a shell conduit. A metal web may be coupled to the metal shell, and the metal web may form a web conduit. A conducting pin may extend through the shell conduit and web conduit. A dielectric seal may electrically isolate the conducting pin from the metal web. The dielectric seal may be formed by a bismuth glass based dielectric sealing material system having at least two of the four components selected from Bi2O3, B2O3, MO, and optionally REO forming a bismuth glass system. MO may be selected from ZnO, BaO, TiO2, and Fe2O3, and their glass making pre-cursors. REO may be selected from CeO2, Y2O3, Sc2O3, Nd2O3, Pr2O3, and lanthanum series oxides. One or more isolators may be disposed within the shell conduit proximate to the dielectric seal and surrounding a portion of the conducting pin.