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