On the Sealing of Electrical Conductors through Glass

Abstract

AT the present time there is great difficulty in obtaining soft glass with a comparatively high coefficient of expansion, suitable for sealing wires into glass tubes, bulbs, etc. The pre-war imported stocks of glass for this purpose are exhausted, and the recently published results of glass research committees do not contain formulas for its manufacture. About three years ago, Mr. George B. Burnside, of the natural philosophy department of the University of Glasgow, discovered a method of hermetically sealing electrical conductors through glass and other vitreous substances. The process is simple, and entirely obviates the use of a “flux” glass; and in view of the present needs, it seems advisable to bring this method again before the notice of those who may find it to their advantage to use it. A general description of the process appeared in the Electrician of July 4, 1913; but the method does not seem to have become so popular as might have been expected from the simplicity and ease of its application. As to the results obtained, the following facts from my own experience may be mentioned as affording proof of its absolute perfection.