hi fellas,
OK,Here it is a bit of a pack a poo ticket, dredged up from here,there and everywhere.I thought this would be easy and I could just pinch it straight out of a Cigweld or BOC catalogue.
Even after taking a womans look,I am not finding much of the needed info, so some of it is from my memory. ( so watch out then!)
Hard soldering, Silver Soldering or silver brazing should not be confused with soft soldering which uses alloys of soft metals such as tin , lead and similar metals.

When a metal is heated up to temperatures approaching melting point, the crystals that the metal is formed from, spread apart, opening up microscopic voids or spaces. The idea behind hard soldering is to flow a molten alloy into those areas when at maximum expansion.
It is the amount of zinc in silver solder which controls melting points of various S/Brazing alloys.Extreme care must be taken when heating to avoid overheating the molen alloy which will flash off the zinc as a vapour. In some instances it is only the difference of a second or two of overheating and the alloy flashes.

The following was cut and pasted from the SBAA web site which seems about the only source of aussie current info.

I have added below that, column markers for No,s, soldering temps, and alloy percentages. Below that again is what I can remember of the colour coding. I can’t find Aussie net references on those as yet.


SB 18 700-780 18 40 25 17 - - Steel and copper alloys.
Reasonable ductility.
Filling capability.
SB 30 600-690 30 28 21 21 - - 'as above'
SB 34 LT 610-670 34 22 24 20 - - Steel and copper alloys. Fluid properties.
SB 34 A17 620-690 34 26 22 18 - - Larger plastic range than SB 34 LT.
SB 35 607-702 35 26 21 18 - - Steel and copper alloys. Filling capability.
SB 38 605-650 38 20 22 20 - - Superior ductility, melting range and strength. Fluid properties.

Suitable for steel, stainless steel and copper alloys.
SB 42 610-620 42 17 16 25 - - 'as above'
SB 45 607-620 45 15 16 24 - - 'as above' Blue tip l
SB 50 620-640 50 15.5 16.5 18 - - 'as above'
SNI 50 645-685 50 15 16 16 - 3 Specialised alloy for stainless and carbide steels.

CADIUM FREE ALLOYS
SB 30 CF 650-750 30 35 32 - 3 - Steel and copper alloys. Filling capability.
SB 34 CF 630-730 34 36 27 - 3 - Steel and copper alloys. Improved ductility.
SB 39 CF 650-705 39 30 28 - 3 - Steel and copper alloys. Fluid properties.
SB 402 CF 660-780 40 30 28 - - 2 Stainless steel and other nickel alloys. Carbide steel.
SB 44 TCF 675-735 44 30 26 - - - Copper and steel alloys. High strength
SB 45 CF 640-680 45 27 25 - 3 - Copper and steel alloys. Fluid properties.
SB 56 CF 618-650 56 22 17 - 5 - Copper and steel alloys. Stainless steel.
SB 60 CF 695-730 60 26 14 - - - Copper, steel and nickel alloys. Ductile high strength
SB 72 CF 778 72 28 - - - - Specialised machine brazing.
Number Temp, Ag, Cu Zn Cd Sn, Ag =Silver, Cu = Copper, Zn =zinc, Cd= Cadnium, Sn =silicon
Yellow tip 2 % Silver
Silver tip 5% Silver
Brown tip 15% Silver
Alloys with cadmium are not suitable for use with beverage or food applications.