Silver soldering is a technique that has been used for centuries in jewelry making and model engineering.
But as technology advances, so do the materials used in silver solder.
Learn about the latest forms and melting temperatures of silver solder and how they can improve your soldering experience.
Table of Contents
The melting point of silver solder
The melting point of silver solder can range from under 200°C to greater than 360°C, depending on its composition and zinc content.
Silver solder is commonly used on metals like brass, copper, and silver because it forms a strong bond and has a relatively low melting temperature compared to the metals being joined.
Achieving the right melting point is crucial for ensuring clean, properly soldered joints.
Silver solder is often preferred in model engineering and jewelry making, as it provides a robust bond and a visually appealing finish.
It is important to note that there is no industry standard for the exact melting temperatures of silver solder; each solder manufacturer may have its own specifications.
Therefore, it’s essential to know the specific melting point and alloy composition of the silver solder being used to ensure proper heating and consistent results in the soldering process.
Using a reliable solder source like a Burrell nameplate is also helpful in maintaining accountability and quality control in the soldering process.
Types of silver solder
There are three primary types of silver solder, classified based on their melting temperatures: Easy (705-725°C), Medium (720-765°C), and Hard (745-780°C).
Each type of solder has its own applications and properties that make them suitable for different soldering tasks, such as delicate work, fine silver filigree, and more robust joints.
Easy solder, also known as extra easy solder, has the lowest melting temperature and is best suited for delicate work and repairs when there is a risk of overheating previously soldered joints.
Medium solder is a versatile option and can be used for various tasks, offering a balance between melting temperature and strength.
Hard solder, with the highest melting temperature, is best suited for more robust work, such as bezels and main structural joints, where higher heat resistance is necessary.
Silver solder also comes in various forms, such as hard metal rods, flux coated hard rods, and solder paste in a syringe.
The solder form chosen is typically based on personal preference, as well as the specific requirements of the task, such as the type and size of the joint, and the level of precision required.
Flux, a crucial component in the soldering process, is often included in the solder itself (as in flux coated hard rods or silver solder paste), or it can be applied separately to ensure a clean, oxidation-free joint.
When silver soldering, it’s crucial to choose the correct type of solder for the job, ensuring the appropriate melting temperature and strength characteristics for the specific metals being joined.
Utilizing proper ventilation, heating, and flux application techniques will further contribute to successful soldering experiences and produce high-quality, aesthetically pleasing results.
Flux for silver soldering
Flux is an essential component in silver soldering, as it helps prevent the formation of oxides and other unwanted substances that can deteriorate the quality of the soldered joint.
Fluxes for silver soldering contain potassium salts or fluorides and borates to ensure cleanliness and proper flow of solder during the soldering process.
There are several commercial flux products available that can be used in conjunction with silver solder.
When choosing a flux, it is important to select one that is compatible with the metals being joined and the type of silver solder being used (easy, medium, or hard).
Using a good quality flux will help achieve consistent results and prevent pitting, dirt, or oxidation from affecting the soldered joint.
When soldering, the proper application of flux is crucial. To prepare the parts for soldering, they should be abrasively clean and free from dirt, oils, or any other contaminants.
Then, flux should be applied uniformly to the soldering area, ensuring that the joint surfaces are thoroughly coated.
This will prevent oxidation during the heating process and help the solder flow effectively by promoting capillary action.
Brazing torches for silver soldering
Brazing torches are used in silver soldering to provide the necessary heat for melting the solder and promoting a strong bond between the metals being joined.
Depending on the size and type of parts being soldered, different sizes and types of brazing torches may be required. Torch selection can also be affected by the gas being used (e.g., propane or acetylene) and whether additional oxygen or air supply is needed.
For small and delicate work, such as jewelry making or model engineering, a micro brazing torch that uses refillable butane can be an ideal choice.
These torches provide focused and precise heat, allowing for greater control over the soldering process. If a larger, more robustly built piece is being worked on, a more powerful torch may be necessary to ensure uniform heating and proper flow of the solder.
When using a brazing torch for silver soldering, safety precautions should be taken, such as working in a well-ventilated area and having a suitable hearth in place.
A homemade brazing hearth, often made from firebricks or refractory materials, not only protects the work area from heat and potential damage, but also helps reflect heat back onto the piece, ensuring a more even and efficient heating process.
As silver soldering requires high temperatures to achieve proper melting and flow of solder, it is important to experiment with the torch settings and find the optimal balance between heating power and control, ensuring that the materials being joined are not overheated or damaged in any way.
Kiln Firing for Silver Soldering
Kiln firing is a popular method for commercial silver soldering, as it provides high-quality and consistent results.
The technique involves placing the components to be joined in a kiln, which is then heated to the appropriate melting temperature of the silver solder being used.
This allows for uniform heating of the metals being joined, preventing overheating and oxidation while ensuring proper capillary action and flow of solder.
When using a kiln for silver soldering, it is essential to understand the melting temperatures of the specific solder being used. Silver solder comes in three types – easy (705-725°C), medium (720-765°C), and hard (745-780°C) – each with its unique melting point.
The proper kiln temperature setting is crucial for achieving the desired joint strength and quality.
Moreover, cleanliness is vital during kiln firing silver soldering. The components must be abrasively clean, free from dirt, oils, and oxides, for the solder to flow correctly.
Depending on the solder form, such as hard metal rods, flux-coated hard rods, or silver solder paste, applying flux may also be necessary.
Flux is essential for preventing oxidation, helping the solder flow and ensuring a clean and robust joint.
Anti-Flux Products for Silver Soldering
Anti-flux products, also known as masking materials, are crucial when silver soldering to prevent the solder from spreading to unwanted areas.
This is especially important when working on delicate work like fine silver filigree or bezels; applying anti-flux ensures the solder lines stay precisely where they are needed.
Commercial anti-flux products are available, as well as some homemade options like graphite pencil, Tippex, and jeweler’s rouge.
When using an anti-flux product, the areas to be masked should be clean and free of any dirt or oils. Applying the anti-flux evenly and with care will aid in achieving a neat and tidy joint.
After applying the anti-flux, the components should be heated at the specific melting temperature of the silver solder being used.
During the heating process, the solder will flow towards the heat source and be restricted to the unmasked areas, preventing sloppy joints and potential repairs.
It is important to note that even with the use of anti-flux products, ensuring proper ventilation, heating, and flux application remains crucial for successful silver soldering.
Further, understanding the spread between the melting point and flowing temperature of solder used can aid in preventing issues such as pitting, overheating, and solder starvation.
Through practice and experimentation with anti-flux products and other soldering techniques, one can achieve quality soldered joints in their metalworking projects.
