Soldering and brazing are essentially the same practice, but the only difference is the temperature of the flame used. The American Welding Society deems soldering as a joining process that takes place under 840 degrees Fahrenheit, and brazing as a joining process using a heat of 840 degrees Fahrenheit or higher. Nonetheless, most soldering is done between the temperatures of 350 and 600 degrees Fahrenheit, and brazing is usually done between 1100 and 1500 degrees.
Choosing between soldering and bracing depends on the conditions of the welding job as well as the requirements of the governing construction codes. Solder joints are used for systems that are as hot as 250 degrees Fahrenheit, while brazed joints are adequate when a system's temperature is as high as 350 degrees or where greater joint resiliency is necessary.
There is another essential detail to consider when choosing between soldered and brazed joints. Although brazed joints are ideal for systems requiring greater joint strength, the rated pressure of a brazed system can often be less than that of a soldered system due to the greater degree of heat used in its process.
Too many people use inefficient or downright irresponsible techniques when installing their copper tube and fittings. Although soldering and brazing are the most common methods used for joints and fittings, they are the least understood methods as well. A mistake in soldering and brazing copper tubing will inevitably lead to faulty joints and leaking lines. There are many possible errors that can lead to improper installation, including:
– Improper joint preparation prior to soldering
– Lack of proper support and / or hanging during soldering or brazing
– Improper heat control and heat distribution through the entire joining process
– Improper application of solder or brazing filler metal to the joint
– Inadequate amount of filler metal applied to the joint
– Sudden shock cooling and / or wiping the molten filler metal following soldering or brazing
– Pre-tinning of joints prior to assembly and soldering
Soldering and brazing are essentially simple household operations, however it is easy to overlook or forget to complete particular steps in the process. It is by paying attention to these tedious steps that will make the difference between a joint that is strong and one that will be faulty.