. The Dental cosmos. he solders for for 20-k. plate the solders for be employed. Only standard soldersshould be chosen, which are about two karatslower in fineness than the plate for whichthey are stamped. The karat stamp is mean-ingless unless it is used by an honest manu- a hard gold has few advantages in thesegmental denture—rigidity being at- facturer. The writer has assayed solderstamped for 18-karat, and found that itpossessed a fineness of only 13£-k. A stand-ard solder stamped for 18-k. should be ofapproximately 10-k., the dishonest productfalling short by 2* karat
. The Dental cosmos. he solders for for 20-k. plate the solders for be employed. Only standard soldersshould be chosen, which are about two karatslower in fineness than the plate for whichthey are stamped. The karat stamp is mean-ingless unless it is used by an honest manu- a hard gold has few advantages in thesegmental denture—rigidity being at- facturer. The writer has assayed solderstamped for 18-karat, and found that itpossessed a fineness of only 13£-k. A stand-ard solder stamped for 18-k. should be ofapproximately 10-k., the dishonest productfalling short by 2* karats, which representsa theft of about lO^c. per dwt. ATKINSON.—THE SEGMENTAL GOLD PLATE. 439 tained as explained in other parts ofthe paper. It has been found that alloyed with a composition of 80silver to 20 copper or 20-k. gold alloyedwith 78 silver to 22 copper best answersthe purpose. It will now be found that the line ofthe edge of the roof segment is im-printed on the inner edges of the two Fig. Roof segment and right outer segment in-vested in whiting, ready for soldering. Itwill be noted that the turned edge of theouter segment and most of the inner sur-face of the roof segment are covered withthe whiting, firmly packed down, in orderthat both segments may be secure duringthe operation of soldering. outer segments. The outer segments aretrimmed almost to this line. One of theouter segments is then carefully joined tothe middle segment (roof) with sticky-wax, it being well to brace this by shortpieces of iron wire laid crosswise over therim and held by the sticky-wax. Whenthe wax is chilled, the plate is lifted fromthe model and invested in dry whiting,packed around the upper edge of the rimand in and around the roof segment sothat it will be firmly held during theoperation of soldering; the portion heldtogether with sticky-wax must, of course,be left uncovered, the whiting itself hav-ing been lightly pressed into a tin boxof suitable size. (Fig. 5.) Thi
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectdentist, bookyear1912
