[Jewelry making - Article 00269] - [Orchid] Hallmarking and solder

[Ian W. Wright]

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Was: Soldering tube settings together

Hi,

    To hopefully clear up the confusion about solder for hallmarking I
    have copied below the table from the British Hallmarking Act which
    defines the minimum purity of solder which may be used in articles
    sent for hallmarking to any of the UK Assay Offices. In order to
    achieve a reduced melting point the solder alloys will virtually
    always have less precious metal in than the carat metal - the only
    exception I know is maybe enamelling grade solder which is very hard
    and so close to the melting point of the carat metal that can be
    quite difficult to use. I have also copied below a table showing
    representative alloy compositions for various grades of silver and
    silver solders... 

    *FINENESS AND SOLDER  * 

    Precious metal fineness is expressed in parts per thousand by
    weight. 

    ALLOY    U.K. FINENESS            PERMITTED SOLDER
    GOLD      999                            750         
    GOLD      990                            750         
    GOLD      916                            750         
    GOLD      750                            750         
    GOLD      750 Filigree or watch case     740  
    GOLD      750 White                      500      
    GOLD      585 Yellow, Red                585     
    GOLD      585 White                      500        
    GOLD      375                            375         
    SILVER    999                            650         
    SILVER    958                            650         
    SILVER    925                            650         
    SILVER    800                            650
    
    PLATINUM		999		

    Two or more of gold, silver, platinum and palladium to total 950 

    PLATINUM		950   
    PLATINUM		900   
    PLATINUM		850   
       
    *The excessive use of solder is not permitted.  * 

    Silver                Type                              M.P. Deg C 
 
    95.84Ag, 4.16Cu           Brittania Silver
    92.5Ag, 7.5Cu             Standard (sterling) silver           920
    92.5Ag, 5.75Cu, 1.75Cd    Standard cadmium silver
    92Ag, 8Cu                 Silver-rupee                         920
    90Ag, 10Cu                Silver U.S. coins                    890  
    80Ag, 20Cu                Jewelry                              820
    80Ag, 13Cu, 6.8Zn         Silver solder, hard
    70-5Ag, 20-3Cu, 5-7.5Zn   Silver solder, medium 
    66Ag, 23Cu, 10Zn          Silver solder, French
    63Ag, 30Cu, 7.5Zn         Silver solder, common
    55Ag, 29Cu, 12Au, 5.5Zn   Gold solder, very easy melt
    70Ag, 25Pd, 5Co           Platinum substitute (Cooper's)
    73Ag, 27Pt                Platinum solder                      1160
    70 Ag, 25Pt, 5Ni          Platinum substitute (Cooper's)
    66.7Ag, 33.3Pt            Platinum silver                      1230
    40Ag, 40Sn, 14Cu, 6Zn     Silver solder, Bu. Stands 

    this is from http://tinyurl.com/32d33b 

    and a little more............  from Cupalloys web page  
    http://tinyurl.com/yq4mwe

    467 is a hall marking quality, cadmium free silver solder with a
    minimum silver content of 67%. 

    It is available ex stock as wire 0.5mm dia in 1 metre lengths. Price
    £4.80 per metre incl P&P 

    It is available, ex stock, in four grades - "Extra Easy",
    "Easy", "Medium" and "Hard" to enable two joints to be made on
    the same article. All have a narrow melting ranges to produce neat
    strong joints. 

    "467 Extra Easy"
    68%Ag 20% Zn 13% Cu
    Melting Range 680 - 700 deg C

    "467 Easy"
    67% Ag 11% Zn 22% Cu
    Melting range 700 - 720 deg C.

    "467 Medium"
    74%Ag 7% Zn 19% Cu

    "467 Hard"
    76% Ag 6% Zn 28% Cu
    Melting range 750 - 780 deg C.

    The alloys are available ex stock as wire 0.5mm dia x 1 metre
    lengths. Price UKP4.50 per metre incl P&P 

    The "Easy" grade is also available in wire form at 0.25mm dia.
    Price UKP3.70 per metre incl P&P. 

Best wishes,
Ian
Ian W. Wright
Sheffield  UK


 
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