Solder is a fusible metal alloy with a melting point range of between 90 and 450 degrees Celcius. It is used in conjunction with soldering; solder is melted to join metallic surfaces together. Soldering can be performed in electronics, jewelry making, and the building industry, just to name a few applications.
Solder can either be soft solder or hard solder. Soft solder will contain high amounts of soft metals such as lead or tin and are used primarily to bridge a gap. Hard solders, on the other hand, such as silver solders, are used to connect two pieces of metal together by expanding into the pores that are opened by high temperatures. Like silver solder, hard solders comprise a high-temperature metal like silver with a small proportion of tin to lower the melting range. Hard solder joints will not become brittle with successive heating like soft solder joints do and can also be filed flush due to their strength and strength of solder.
WBT Silver Solder wire
In the picture below, you can see an example of silver solder wire. It is a quality product that contains a 4% fine silver content. The halogen-free flux is gentle on precious metal surfaces. This silver wire has a very low melting point at 180 degrees and can be used for connecting hi-fi connectors because it has a lower electrical resistance. Other uses include electronics, fine wires, electrical joints, and working with precious metals.
Silver Solder Paste by Fusion
If you opt for a silver solder paste, you will end up with something like this one 0z tube from Fusion. What you have here is a syringe holding silver solder that has been mixed with flux. It is free-flowing and straightforward for you to be precise in direction with it. These types of silver solder paste can be used with a soldering iron or even in a furnace. You will find that most pastes are lead-free, with many being cadmium-free as well. And the flux that is mixed up with the solder will be a strong flux that you can actually use with stainless steel. These solder pastes are a very clean and convenient way to use silver solder.
Working With Silver Solder
Silver solder is limited in comparison to soft solder in that it will not bridge across gaps. So for the silver solder to work correctly, you need a joint that is flush and tight. You can perform a little task yourself to see if a joint is tight enough. All you need to do is hold the joint up to the light, and if you see the light through the joint, it is not tight enough.
Dirty joints always have an adverse effect on silver solderers. Such things as grease, charcoal, and even dust will prevent silver solder from free-flowing into a joint. You need to ensure that all joints are thoroughly cleaned using fine sandpaper and then rinsing with water. It is advisable to wear gloves as well when working with silver solder as fingerprints on or around a joint can also cause problems.
It would be best if you used flux with silver solder. Flux slows down any fire scale formation, which is formed when the copper in alloys oxidizes. Fire scale impedes the flow of solder. Before soldering a joint, you should cover the whole joint with flux and do not worry about being generous with the flux either. Any excess flux will simply burn off.
When it comes to heating and soldering with silver solder, the heating up must be done quickly. If you do not heat up quickly, you will find that the flux will burn off, resulting in the fire scale forming. Some soldering irons, such as the small propane or butane versions (Dremel Versatip), simply do not heat up quickly enough due to their lack of power. So when it comes to choosing and buying a soldering iron, you must purchase the hottest torch that you can afford. Having an unsuitable soldering iron is one of the causes of most significant problems when it comes to soldering.
Silver solder has a habit of collecting tarnish on itself. If the tarnish build-up is bad enough, it will impede any flow. So always clean your silver solder before cutting it.
You may already know this, but solder does not flow according to gravity. It will flow in any direction where there is heat because of its capillary action. Because of this, if the silver solder is not touching both parts of a joint simultaneously when it liquefies, you will see that the solder will actually bead instead of flowing into the joint. This means that you will not solder the joint. So always ensure that both parts of the joint come into contact with the solder.
When it comes to soldering, most beginners and even those who are more experienced tend to perform a cardinal sin. They lose patience and become frustrated when the solder does not liquefy properly when the rest of the metal is red hot. So what they do is aim the soldering iron right at the solder, hoping to speed up the liquefying process. But this is not what will happen. Instead, the increased heat on the silver solder will burn out the lower-temperature metals. This means that the solder will have an even higher melting point than the surrounding alloy, and you will end up melting your base metals instead. One significant rule for soldering is never to heat the solder but to heat the joint. If you remember and practice this, you are halfway to becoming efficient soldering.
Silver Solder Sheet
The final option for obtaining silver solder is to have it in sheets, as you can see in the picture. The sheets can vary in quality and characteristics depending upon which type and quality of sheet you choose. These sheets are very light, flat, and convenient to store. When you require some solder, it is straightforward to clip off the needed amount you desire. Everyone has their own specific way of having their silver solder, but of the three options available, this is the one that I least favor here, but if there were no other options, then I would still add it to my soldering kit.