The Difference between Soldering and Brazing

A lot of people can be confused by two different joining techniques called soldering and brazing. They are similar in that both procedures involve melting a metal, called a filler, to conjoin at least two components but doing it at a temperature below the melting point of the base material. So how do they really differ?

The liquidus, otherwise known as the melting point, is what sets the two joining techniques from each other, as defined by the American Welding Society. Soldering uses fillers that melt at 450°C and below. Brazing, on the other hand, involves fillers that melt at above 450°C.

With regard to strength, soldering usually leads to weaker joints because of the lower temperatures involved in the process. That may not necessarily make it undesirable, though, as soldering can be a better, if not the only, option for a particular joining task. Remember the high temperatures involved in brazing? That would damage small or sensitive electronic components, so brazing is out of the question. Brazing is more applicable to tasks that require strength and if the parts to be conjoined are not that sensitive to heat.

Both soldering and brazing require heat which is applied in different ways—resistive heating, through flames, using a laser, inductive heating, through combustion, and radiant heating among others. Both techniques can be done in the open or in a protective environment. In open air, a flux is usually required to reduce the surface oxides, allowing wetting and the flow of the filler metal.  A protective environment usually involves a vacuum, inter, or active atmosphere. Both procedures are also used to join metals, metallic alloys, composite materials, ceramics, and other materials both like and dissimilar.

Now the choice on which technique to use is dependent on a lot of factors which may include operating temperatures and service loading, as previously mentioned. Most substrates are easily damaged when using high temperature, which is what filler metals require melt in the brazing process. The substrate’s wettability by the brazing or soldering filler metal is another factor to be considered. In certain fluid transport systems like HVAC, flux residue needs to be removed so this should also be taken into account when choosing between brazing and soldering. Other factors include closed systems that can be difficult to clean after joining, which might then require self-fluxing materials, and situations which might cause abrasive wear common in moving components.

So which is right for your requirement?

Selecting the joining technique appropriate for your requirement is best left to experts and specialists. For your plumbing repairs, replacements, and maintenance, contact our friendly and reliable plumbers from Sin City Plumbing! We have service specialists well-trained in the science of both soldering and brazing, and they can decide which option best suits your needs.

Sin City Plumbing is not responsible for, and expressly disclaims all liability for, damages of any kind arising out of use, reference to, or reliance on any information contained within this blog. While the information contained within the site is periodically updated, no guarantee is given that the information provided in this blog is correct, complete, and up-to-date.

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