A residential or business HVAC system handles the hard work of keeping the building cool in the summer and warm in the winter as well as providing ventilation. A cavity in the ductwork can prevent the system from functioning properly and lead to high energy bills, which it is crucial to quickly identify and fix a suspected leak.

For HVAC technicians, identifying and fixing is part of the territory. But soldering damaged ductwork properly can be tricky even for the most advanced craftsmen. With that in mind, we've compiled a few tips and tricks to help make soldering HVAC ductwork simpler, whether you're in the field, at the shop or at home. 

Soldering vs. brazing

Although the two techniques are similar, it’s important to be able to tell the difference between soldering and brazing.

Both techniques require heating the base metal to a high enough temperature so that  the connective material can actually bond with it, but the temperature you need to reach is what determines whether you’re soldering or brazing.

Soldering takes place at temperatures less than 840 degrees Fahrenheit while brazing needs the base metal to reach temperatures higher than 850 degrees. You use a torch for both, but you'll need an oxy-acetylene torch for brazing and a MAPP gas or propane torch is sufficient for soldering.

The technique you’ll use, and the solder or brazing that is necessary, will depend on the type of pipes or ductworks being connected or repaired. Brazed joints tend to be stronger than those that are soldered, but brazing is needed only in certain circumstances. Because of the higher temperature needed for the process, it can’t be used in applications where you might be working near nylon or rubber tubing that could be damaged by the heat.

Safety is key

HVAC technicians face a number of different hazards in the line of duty. Soldering a piece of ductwork on site can be dangerous — the extreme heat generated during the soldering process could ignite nearby combustible materials if the technician doesn’t take enough precautions.

There is also the potential for exposure to refrigerant or other dangerous substances as a result of damaged HVAC pipes or ductwork. Using the correct personal protective equipment in these cases can help technicians stay safe on the job. Fall-arrest systems should be standard equipment for any technicians who are working off the ground, even as little as 10 feet up.

The right tools

HVAC ductwork soldering is not something that should be attempted by the average DIYer. It requires many specialty tools and some techniques that can be difficult to master. Make sure your technicians have all of the proper tools and training to properly handle the soldering equipment. This training doesn’t just stop when they’re hired though — continuing their education as new techniques or equipment become available can make your process more efficient and help to keep your technicians safe on the job.

It might not seem like much, but training your technicians is one of the best things you can do for them.

Soldering is a skill that all HVAC technicians will need to use at some point, so it’s important that your technicians are trained correctly and have the proper tools at their disposal, whether they need to solder some ductwork at the shop or out in the field. Keep your technicians informed of any new techniques that come about, and keep them trained on any new equipment you purchase to make their jobs easier. It will end up making the process that much more efficient and help to keep your crew safer in the meantime.