HOW IS SILVER SOLDERING CREATED?
Let’s quickly see what is meant by soldering:
By soldering we mean the joining of two or more metal parts in order to obtain a single, strong body. In this case we do this by preparing an alloy whose melting point is lower than the melting point of the alloy of the object to be soldered, and which allows the multiple metal parts to be joined together using heat.
This type of soldering, which is what we usually use in jewellery, is called BRAZING SOLDERING.
Brazing soldering consists of melting a filler metal alloy with a lower melting point than the metals of the parts to be joined, so that the latter remain intact without melting with the soldering alloy.
Silver soldering alloys contain varying percentages of copper, zinc, cadmium, phosphorus and tin and are used to solder silver at 800/°°°, 925/°°° and even 999/°°° (in the latter case, Ag a925/°°° is used for soldering; )
Not all of them, however, can be prepared in a small workshop because some require special equipment and precautions. In our workshops we usually use those prepared with (Silver, Copper Zinc) which we can use according to need in 3 different grades:
STRONG – MEDIUM – SOFT.
For obvious reasons, the weld must have a lower melting point than the metal to be welded.
Example Silver 999.9 melts at 961°, so to weld it we directly use 925 silver which has a melting temperature of 893°.
From this we deduce that the soldering of 925/°° silver will have to melt at a temperature below 893° precisely in order to perform the brazing operation.
Usually, except for very complex jewellery made in high jewellery, only one type of soldering is used in jewellery.
Therefore, we consider in our workshop making solder that has technical characteristics and versatility and a broad spectrum of use so to speak, i.e. that we can use it in 90 % of cases: from the construction of objects to the repair of existing jewellery.
Medium soldering may be fine in most cases, but let us see below the formulas for all types of silver soldering.
As we have said the 3 metals we will use to create the various soldering grades for silver are :
Ag Cu Zn ( Silver, Copper Zinc )
Which we are going to alloy with the following percentages :
STRONG (TF-700-750° approx.) Ag 60% Cu 22% Zn 18%
ex: 10 g of solder = 6 g of Ag 999.9 2.20 g of Cu 1.80 g of Zn
AVERAGE (TF- approx. 650-700°) Ag 60% Cu 18% Zn 22%
e.g.: 10 g of solder = 6 g of Ag 999.9 – 1.80 g of Cu – 2.20 g of Zn
TENER (TF -600-650° approx.) Ag 60% Cu 14% Zn 26%
e.g.: 10 g of solder = 6 g of Ag 999.9 1.40 g of Cu 2.60 g of Zn
We have thus created our welding alloys with several melting grades, so that we can use them in the most complex processes where several welds are required in the same jewel, so that during processing after the first (strong) welding we will use the second (medium) and if required the third (soft).
In this way we avoid running the risk of re-melting the first soldering while performing the second and so on, due to the fact that the metal of the second soldering liquefies at a lower temperature than the melting temperature of the first, and we do not run the risk that the assembled parts already soldered may be removed or desoldered.
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Happy Work Artists
Academy Of Goldsmith Arts