Glass Fiber Insulation Used for Brass Furnace.--(The Iron
Age, Vol. I5o, No. I3.) With mica listed as one of the nation's critical materials, the Western Cartridge Co. has successfully used Fiberglas tape in place of mica as coil insulation in the primary coil of induction-type brass furnaces. The 38 furnaces of this type installed in the Western Cartridge Co. plant have a sleeve-shaped form composed of ceramic material which retains the helical flat copper coil to form a double helix composed of alternate layers of copper and Fiberglas tape. Insulation between turns in the coil is required to prevent short circuiting. It is said that the use of the Fiberglas tape insulation made it practicableto increase furnace temperatures to the point where it was possible to produce five pours of 1500 lb. each duringeach 8 hr. shift, whereas with the mica insulation the limitwas three poursof x5oo lb. each during each 8 hr. shift--an increased production of 300 lb. per shift, per furnace. The cost of the glass fiber insulation was 50 per cent. less than the mica it replaced. The number of man-hours required to install the Fiberglas insulation was less than half that required for the installation of mica. Approximately IOOO of the induction-type furnaces are used by the large brass companies. Most of these companies follow the practice of rebuilding their own cores when such rebuilding is necessary. R. H. O.