If you work in plumbing, electrical work, or welding, you already know the importance of joining metals together securely. Ensuring a strong bond is imperative to the longevity and safety of your work. There are a few different ways that you can join metal, though, including aluminum to copper brazing silver solder.
Choosing between copper brazing or silver soldering isn’t always a clear choice, though, and you probably have questions — is one method stronger than the other? Can I use aluminum to copper silver soldering for any application? Find the answer to these and other FAQs so that you can tackle your next job with confidence.
Difference Between Brazing and Soldering
Brazing and soldering are two different routes that get the same result. Both entail attaching metal pieces to each other, and both can be used in applications such as plumbing, electrical wiring, or construction. Despite these similarities, brazing and soldering are not interchangeable, and each follows a slightly different procedure than the other.
Brazing
Brazing refers to the process of joining metals together, most commonly with a zinc and copper alloy. Zinc and copper are the metals of choice for brazing due to their high melting point and strong bond. This alloy allows a brazed joint to sustain high levels of stress, and it’s one of two important characteristics that differentiate brazing from aluminum to copper silver soldering.
The second characteristic that differentiates brazing from soldering is the temperature used to form a joint. Brazing typically occurs at a higher temperature than soldering, with most professionals citing 840°F as the threshold. Joints that are made below this temperature are referred to as solid phase bonding because the base material is not completely melted during the process. Brazing, on the other hand, entails liquid-solid phase bonding. This means that the higher temperature causes the filler metal to melt as pieces are joined together.
Soldering vs Silver Soldering
There are several different types of soldering that you can use, and each is ideal for a different application. The difference often lies in the type of material used. Common options include the following:
- Tin
- Bismuth
- Antimony
- Indium
- Brass
- Copper
- Silver
Copper is one of the most common metals used in soldering, but there are a few reasons why you may opt for silver. Silver soldering is different than other types of soldering because it occurs at temperatures that are comparable to brazing — above the aforementioned 840°F threshold — but often requires the use of a blowtorch to create a joint. This differentiates it from other types of soldering, which more commonly use tools such as a soldering iron.
Pros and Cons of Brazing
Despite the versatility of silver solder, brazing is sometimes a better option. Still, it has its own pros and cons that you should be aware of. Some of the advantages include the following:
- Can be used to bond metal and nonmetal materials
- Allows for more precise control of the materials
- Joints are typically clean with minimal need for finishing
- Joints are resistant to corrosion
These advantages should be weighed against some of the disadvantages that brazing can incur when compared to aluminum to copper brazing and silver solder. These downsides include the following:
- Joints may not be stable when exposed to high temperatures
- Joints typically are not as strong as those created with welding
These pros and cons illustrate the fact that brazing is appropriate for some — but not all — applications. It’s important to closely consider the stress a joint must sustain before choosing between soldering or aluminum to copper brazing.
Pros and Cons of Soldering
Soldering also has unique pros and cons that must be taken into consideration. It offers the following advantages to users:
- Low power consumption
- Minimal risk of thermal distortion
- Process can be automated
- Different material types may be joined
- Heat does not alter metal’s microstructure
There are also some downsides that may make aluminum to copper brazing preferable to aluminum to copper silver soldering:
- Joints might be too weak to withstand high temperatures
- Soldering is not suitable for heavy metal materials
- Large materials cannot easily be joined with soldering
Choosing aluminum to copper brazing or silver solder can be difficult if you don’t know what to look for. The right choice depends on the materials you are trying to join as well as the size of the material.
Can You Silver Solder Aluminum to Copper?
No, aluminum and copper cannot be soldered due to the different resistivity and potentials between the two materials. The point of contact will cause the aluminum to oxidate, and this will compromise the bond. There are some special connector compounds that may allow the two materials to be joined, but it cannot be done via soldering.
Relationship Between Copper and Aluminum
Although you cannot solder aluminum and copper, the two metals do share a relationship. Both materials are highly conductive, which means that both can be used to conduct electricity. This is the main characteristic the two materials have in common, though, and aluminum is rarely used in modern electrical applications. This is because it is about 40% less conductive than copper, and it may also increase the risk of electrical fires.
Do’s and Don’ts of Silver Soldering
Silver soldering might not be the right method for joining aluminum and copper, but it can be safely used for many other applications. Of course, its safety depends on the user’s ability to follow the correct procedure and avoid dangerous mistakes. Some of the practices that you should follow while soldering with silver include the following:
- Always return the soldering iron to its holder
- Use a cartridge extractor, not pliers
- Keep the surface of your iron’s tip clean
Remember to avoid these mistakes that may compromise the results of your silver solder:
- Don’t use a temperature that’s too high
- Don’t put too much pressure on the iron
Following these tips will help you minimize the risk of injury and ensure that the finished product is highly durable.
Can You Braze Aluminum to Copper?
Yes, you can use brazing to join aluminum and copper together. In fact, this is a common practice in many industries due to copper’s heat transference and aluminum’s affordability. When used together via brazing, these materials can provide a strong bond.
Do’s and Don’ts of Brazing
In order to see the best results from brazing, you need to ensure you’re using the application the right way. You can start by following these important do’s:
- Do wear personal protective equipment to prevent inhalation of fumes
- Do ventilate the area with fans or an exhaust hood
- Do thoroughly clean the base metals
You should also be sure to avoid these brazing don’ts:
- Don’t provide insufficient flux
- Don’t braze metals you aren’t familiar with
- Don’t braze a metal that may volatilize
Brazing can be a highly dangerous task due to the fumes that are created at high temperatures, but if you follow these do’s and don’ts, you can keep yourself safe.
Is Aluminum Brazing as Strong as Welding?
Aluminum brazing is generally faster than welding, and in most cases, it is just as strong, too. Welding is considered the golden standard for joining metals, but further examination shows that the two methods often offer comparable results.
When to Use Aluminum Brazing
Aluminum brazing is best for repairing iron or aluminum materials. You can use aluminum to copper brazing for filling holes and repairing cracks, for example. It can also be used for creating new joints between a range of different metal materials. Some of the applications it’s most commonly used for include the following:
- Gas piping
- Water piping
- Refrigeration tubing
Aluminum brazing is ideal for these uses because it offers superior strength and resistance to wear.
When to Use Welding
There are many applications that would benefit from a welded joint rather than a brazed joint. Some examples include the following:
- Joining steel or steel alloys
- Joining metal that is at least one inch thick
It’s important to note that welding and brazing are not mutually exclusive. They can be used in conjunction in order to achieve a strong bond — especially if you want to strengthen an existing bond. You can achieve this by brazing over a welded joint.
Which Is Stronger, Brazing or Silver Soldering?
In most cases, brazing is stronger than silver soldering. This is due to the higher temperature that brazing is done at, as well as the alloys that are commonly used in the brazing process. Still, when you are deciding whether aluminum to copper brazing or silver solder is best, it’s important to choose the method that’s the safest — and in some cases, this will be soldering instead of brazing.
How to Make a Strong Bond With Brazing
Making a strong bond with brazing requires several important components. First, in order to achieve the strongest bond possible, you should ensure that you’ve chosen a filler metal that will provide sufficient capillary action. Capillary action is the ability of the metal to liquidate and fill a narrow channel.
Once the filler metal liquifies and fills the gap between the two pieces, they should be joined. You should wait for the joint to solidify, and then you must check it to ensure that the joint is secure. To do so, simply dip the joint in hot water to dissolve any residue. This is called the post-braze joint cleaning, and it is necessary to remove any residue that may compromise the strength of the joint.
How to Make a Strong Bond With Silver Soldering
You can also make a strong bond with silver soldering. To do so, you should first ensure that the pieces you want to solder are completely clean. You can accomplish this with a file or sandpaper. You should then apply flux to the pieces that you intend to solder and position them closely together, with a minimal gap between them. Both pieces should be broadly and uniformly heated. Finally, the silver solder should be applied and heated until it displays a red glow.
At this point, the silver solder should be flowing into the joint, and you can begin to pull the heat away. You should allow the joint to solidify and cool down before sanding. Sanding will remove any impurities and oxidation that may have emerged during the soldering process, and it will also help you test the joint to ensure you’ve achieved a strong bond.
Why Would You Braze Instead of Solder?
You may choose to braze a joint rather than soldering it if you need a joint that will withstand substantial pressure. There are many other instances wherein brazing is preferable to soldering, too, including the joining of dissimilar metals.
Brazing for Plumbing and Welding Applications
One of the most common uses of brazing is in plumbing, although aluminum to copper brazing and silver solder can both be well-suited to this application. Brazing is frequently used to join pipes because it ensures a strong, long-lasting joint. First, pipes must be cut and cleaned, and a fitting should be prepared to braze the two pieces.
You can also use brazing as a part of the welding process. Because brazing is done at a lower temperature than welding, it’s a great way to prepare a joint for welding and create a precursory bond that the weld will then reinforce. This is less common, though, because brazing and welding manipulate metal in different ways.
Understanding Aluminum to Copper Brazing Silver Solder
Aluminum to copper brazing and silver solder both offer great options for securely joining metals together. Whether you’re a plumber, welder, or electrician, it’s important to know the difference between aluminum to copper brazing and aluminum to copper silver soldering. Understanding these concepts will help you make the right decision when you’re on the job, and the right decision ensures that your work is strong, durable, and high-quality. Find out how to learn brazing, soldering, and welding skills through a job training program. You can become licensed in your state and start a promising new career.