Soldering vs. Brazing: The ultimate pressure test

It's a bit like the debate between Pex A and Pex B—everyone wants to know which one to use and when. Well, today, I'm diving into brazing vs soldering - which seem similar, but there are very big differences.

Let's start with soldering. Soldering involves joining metal pieces together using a filler metal that melts at temperatures below 850 degrees Fahrenheit. It's a common technique used in potable water systems, especially those utilizing copper pipes. To me, soldering is a fundamental skill that every plumber should master. It's an old-school technique that has stood the test of time.

On the other hand, brazing is reserved for specific applications, such as medical gas systems or repairs under slabs where structural support is crucial. Unlike soldering, which uses a lower-melting-point filler metal, brazing employs a higher-temperature filler material like silver solder. This results in stronger joints capable of withstanding higher pressures.

Now, let's get hands-on with these techniques. I set up a blast chamber to put both soldered and brazed joints to the test. Safety is always a priority, so I got my PPE on. I take this very seriously.

First up, soldering. I meticulously cleaned the fittings and pipes, applied flux, and soldered the joints using a turbo torch. With precision and care, I ensured the solder flowed evenly, creating a solid bond between the components.

Next, brazing. Without the need for flux, I assembled the fittings and pipes before heating them with a brazing torch. The higher temperatures allowed the silver solder to flow into the joints, creating robust connections.

With both joints prepared, it was time for the ultimate test—subjecting them to high pressure. I connected the test pieces to the blast chamber and gradually increased the pressure. The results were astonishing.

Despite reaching pressures of up to 7000 psi, neither the soldered nor the brazed joints failed. However, there was a noticeable difference in the size of the blowouts. The soldered joint exhibited a slightly larger blowout compared to the brazed joint, highlighting the strength of brazing under extreme conditions.

It's clear that both soldering and brazing have their place in the plumber's toolkit. Soldering excels in potable water systems, providing reliable connections for everyday use. On the other hand, brazing offers unmatched strength for critical applications where durability is paramount.

This was a fun experiment, but let me know which one you use the most!