Glass Melting


Industrial Processing


Mo, Mo30W, MoZr02, coated Mo


Higher energy efficiency, lower capital cost/unit of capacity, more control over applications. Fewer environmental emissions less dependence on radiant heating


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    Glass Melting Electrodes

    Superior Products for Critical Glass Operations

    To improve the glass industry’s critical applications in melting, homogenizing, feeding and shaping of glass products, H.C. Starck Solutions offers superior products and services:

    • Molybdenum Glass Melting Electrodes (GME)
    • Mo Sheet and Plate for Tank Reinforcement
    • Oxidation Protective Coating
    • Tubular Targets for Large Area Coating
    • Recycling

    H.C. Starck Solutions molybdenum glass melting electrodes (GME) provide the industry with superior quality and the highest product standards for efficient glass melting and electric boosted melting. The high temperature strength and rigidity of molybdenum electrodes, plus the inherent electrical properties of molybdenum, provide maximum operating efficiency. The exceptional purity level of H.C. Starck Solutions molybdenum electrodes (99.95 % minimum) achieves outstanding resistance to chemical corrosion, degradation and minimizes detrimental glass discoloring.

    We offer a variety of electrodes for the most demanding glass melting processes:

    • Standard and tapered threads including standard metric threads
    • GMEs from 1.25″ (32 mm) to 8″ (203 mm) in diameter
    • Machined or centerless ground surfaces for assurance of concentricity and straightness
    • Custom fabricated top mounted electrodes and bi-metallic
    • Uniform recrystallized grains for creep resistance
    • High purity (99.95 % minimum)
    • Bubble free, low carbon electrodes

    Molybdenum is the “BEST” Choice

    H.C. Starck Solutions molybdenum is the “best” choice for electric heating in the glass melting process:

    • Excellent strength and stability at temperatures over 2000 °C
    • High thermal and electrical conductivity
    • Low coefficient of thermal expansion (CTE)
    • Resistance to corrosion
    • Minimizes detrimental glass discoloring
    • Good machinability

    Traditional and Premium Electrodes

    H.C. Starck Solutions offers our high purity molybdenum (Mo) and premium molybdenum-zirconium (MoZrO2) glass melting electrodes. Available coated and uncoated with conventional threads and tapered threads for ease of installation.

    Glass Melting Electrode Chemical Characteristics1)

    Chemical compositions of molybdenum powders for glass melting electrodes with minimum and maximum limits are as follows:


    Element Standard
    Mo min. 99.95 %
    C max. 0.005 %
    Ca max. 0.003 %
    Cu max. 0.002 %
    Fe max. 0.005 %
    Mg max. 0.001 %
    Mn max. 0.001 %
    Ni max. 0.0015 %
    Sn max. 0.003 %

    Mass fraction in %
    1) Information on testing methods available upon request.



    Element Standard
    Mo (By Difference) min. 98.50 %
    Mg max. 0.001 %
    Mn max. 0.001 %
    Ni max. 0.002 %
    Al max. 0.002 %
    Cu max. 0.002 %
    Pb max. 0.002 %
    Ti max. 0.002 %
    Ca max. 0.003 %
    Si max. 0.003 %
    Sn max. 0.003 %
    C max. 0.005 %
    Fe max. 0.005 %
    Cr max. 0.005 %
    Zr 1.2-1.4 %


    Maximum variations from straightness will be 0.030 inch per foot (2.50 mm per meter). Maximum variation in cut lengths will be +1/4“, -0 inch (+6.35 mm, -0 mm).

    Special tolerances available upon request.

    U.S. and European standard and special threads are available on either or both ends.

    GMEs Produced by Powder Metallurgy

    H.C. Starck Solutions glass melting electrodes (GME) are manufactured from pure molybdenum and supplied to customer requirements by forging and machining.


    Glass melting electrodes will normally be shipped as stress relieved. Material can be supplied in the re-crystallized condition upon request.

    Dimensional Tolerances
    Diameter Diameter Variation Out-of-Round
    Inches mm Inches mm Inches mm
    1 1/4 31.7 +/- 0.015 ± .38 0.015 0.38
    1 1/2 38.1 +/- 0.015 ± .38 0.020 0.51
    2 50.8 +/- 0.030 ± .76 0.025 0.63
    2 1/2 63.5 +/- 0.030 ± .76 0.025 0.63
    3 76.2 +/- 0.040 ± 1.0 0.035 0.89
    4 101.6 +/- 0.040 ± 1.0 0.050 1.27


    p ≥ 10,2 g/cm³


    The material can be offered as forged.

    Ultrasonic Test

    All H.C. Starck Solutions Hermsdorf glass melting electrodes (GME) are inspected by ultra-sonic test according to DIN EN 583.

    Dimensions and Tolerances

    The material can be supplied in the following standard diameters:

    • 32.0 mm (1 ¼“)
    • 50.8 mm (2“)
    • 63.5 mm (2.5“)
    • 76.2 mm (3“)
    • 101.6 mm (4“)
    • 127.0 mm (5“)
    • 152.4 mm (6“)

    Tolerances: +/- 0.5 mm in lengths up to 2.5 m. Other diameters are possible according to customer request.


    Maximum variations from straightness will be 0.030 inch per foot or 1.5 mm / m. Maximum variation in cut lengths will be +1/4”, -0 inch. Special tolerance on request.


    U.S. standard and special threads are available on either or both ends.

    Surface Condition

    Glass melting electrodes will be supplied with centerless ground or machined surfaces of 128 micro inch or better. Minor surface imperfections may be removed by conditioning while maintaining the dimensional tolerance.