What are the proper techniques for using a hot air rework station for soldering and desoldering?

Picking a sodlering iron of the right size is very important, the quality of the soldered joint depends indefinetly on it. The perfect nozzle size would just about cover over half of the portion you want to solder, giving you enough wiggle-room.

Using a hot air rework station for soldering and desoldering electronic components involves careful preparation and technique. For soldering, select the appropriate temperature and airflow, apply flux, and use a sweeping motion to evenly heat the area. When desoldering, apply hot air to melt the solder, gently lift the component, and clean the pads. Practice scrap PCBs, control temperatures, maintain a proper nozzle distance and protect sensitive components. Always follow manufacturer guidelines and recommended practices for specific components.

Selecting the appropriate nozzle is crucial for efficient hot air rework. Consider the size and shape of the component you're working on, ensuring the chosen nozzle aligns with these specifications. Opt for a nozzle that directs hot air evenly and precisely to avoid overheating, solder bridges, or cold joints. Using a nozzle that is too large or small may result in adverse effects. Additionally, choose the right type of nozzle, be it round, square, or bent, based on the specific task at hand. Each type serves different purposes, so understanding the requirements of your project is essential for successful soldering or desoldering without negatively impacting surrounding components or the circuit board.

There are many types of hot air guns where we can have many interchangeable nozzles. We need to take into account the functions and features of our project then to decide the right choice for us. We need to consider the materials used in the project, how much sensitive the components are. Mostly while building circuits a thinner type of reduction nozzles are used which gives a thinner jet of air for soft soldering. The tiny nozzles are really helpful in focusing the airflow over a small chip. Whereas the bigger nozzles are helpful for applications in a big area like huge heat pad sinks.

To ensure precise soldering or desoldering, configuring the temperature and airflow of your hot air rework station is crucial. Refer to the datasheets of the component and solder alloy for recommended temperature ranges. Opt for the lowest temperature capable of melting solder without causing damage to the component or board. Adjust the airflow to a level sufficient for removing molten solder but avoid excessive strength that might displace components or harm the board. Use the temperature and airflow controls on your rework station, adjusting knobs or buttons to achieve the optimal settings based on the specific type and size of the component, solder alloy, and board material in use.

To solder the component, start by applying flux to the board pads using a flux pen, syringe, or brush. Flux aids solder flow, adhesion, and prevents oxidation. Align the component with tweezers or a vacuum pick-up tool. Optionally, use solder paste on pads or component pins. Solder paste, a mix of solder and flux, melts when heated. Hold the hot air nozzle above the component at a safe distance, moving it slowly until solder paste forms a solid joint. Ensure a shiny, smooth appearance and check joint quality by gently tapping the component with tweezers. This method ensures proper soldering with minimal risk of overheating or damaging the component.

Choose an appropriate area to work and use some kind of platform like a table or non-metallic thing below which can absorb heat so that we can touch it while removing setup if necessary. At first apply the solder glue to the points/nodes where elements will be connected. Then choose the correct nozzle type in the air gun. Keep tweezers ready in your hands ready for use. Turn on the airgun and start blowing over the area the glue will spread at first. After sometime the solder joints will start melting and a they will give a shiny look that's when we can confirm that the soldering is done correctly.

While desoldering any component we need to blow the hot air gun over the area of the elements' joints. Keep a safe distance from it and protect your eyes. A spectacle glass can be used while soldering or desoldering to protect our eyes while doing this kinds of work. After hovering over the joints and melting take out the element using tweezers or vacuum pick-up tool to take out the element. A solder suck will be required for cleaning up the excess solder from the area. This solder suck can even be a simple vacuum type solder gun also.