Principles and practice of crown and bridgework : a practical, systematic and modern treatise upon the requirements and technique of artificial crown and bridgework / by Hart J. Goslee.

  • Goslee, Hart J. (Hart John), 1871-1930.
Date:
1907
Catalogue details

Licence: In copyright

Credit: Principles and practice of crown and bridgework : a practical, systematic and modern treatise upon the requirements and technique of artificial crown and bridgework / by Hart J. Goslee. Source: Wellcome Collection.

    47/540 (page 35)
    cedure in either instance indicated is to first thoroughly clean the parts and then fit or burnish into the openin.g a piece of pure gold plate or foil of suitable dimensions, which may be held in place by holding the work in a favorable position to sustain it, or attaching it by the fusion of the flux. A piece of solder somewhat larger than the perforation should then be placed in position, covering same, and likewise held in place, and then heat uniformly applied until the solder becomes firmly attached without complete fusion. In small perforations solder alone will accomplish this end, without the use of a support of pure gold or other metal. Autogenous soldering is the process of uniting J!utO0Cnou$ Soldering* surfaces by immediate inter-fusion, without the use of a lower grade alloy, and while it has no decided advantages, excepting that a joint so made is not increased in stiffness or thickness, and the appearance of a seam of solder is avoided, it is quite easily accomplished in uniting bands and attaching solid cusps to them, in the execution of which the surfaces must be perfectly approximated, re- tained closely in contact, properly fluxed, and held in the flame until union is accomplished by superficial fusion. By a little practice one may become quite skilful, and joints so made usually possess every element of strength. While soft soldering is not to be generally com- Soft Soldering. mended, it is sometimes indicated in emergency cases, where some strength in the union of the parts is required, as in temporary crowns, etc. For such purposes a solder composed of equal parts of tin and lead, or any of the fusible alloys, may be used, either with a soldering iron or by placing them upon an asbestos pad and directing the flame of the burner upon them until the solder fuses. A convenient flux for this work is made by gradually adding pure zinc to hydrochloric acid until the chemical action subsides or the acid refuses to take up more, thus making a solution of zinc chloride, when it may be filtered and is ready for use.