Quick Answer
Soldering is the process of joining metal components with melted solder to create electrical connections. For FPV drone building, you need a temperature-controlled iron (320-380°C), rosin-core solder wire (0.8mm), flux, and a few basic techniques to create reliable joints on flight controllers, ESCs, and receivers.
Why Soldering Matters for FPV Builds
Almost every FPV drone build requires soldering. Flight controllers, ESCs, video transmitters, and receivers all connect via soldered pads. A bad joint can cause signal dropouts, motor desyncs, or complete failures mid-air. Learning to solder cleanly is one of the most valuable skills for any FPV pilot.
You do not need expensive equipment. With the right iron, decent solder, and a bit of practice, most pilots produce reliable joints within an hour.
Essential Soldering Equipment
You need four things: a good iron, quality solder, flux, and a tip cleaner. The Sequre SI012 Pro Intelligent Portable Soldering Iron is a popular choice. It heats up in seconds, maintains stable temperature, and uses affordable tips designed for small-pad work.
For solder, use a rosin-core 60/40 tin-lead wire at 0.8mm diameter. The rosin acts as flux, helping solder flow and bond to pads. Thinner wire gives more control on small flight controller pads.
Flux paste or a flux pen is non-negotiable. Apply flux to every pad before soldering and you get shiny, concave joints. Without flux, solder balls up and refuses to stick.
For a complete set, the UMT FPV Drone Tool Kit bundles soldering essentials with hex drivers and other build tools.
Temperature and Tip Selection
Set your iron between 320°C and 380°C. Lower temperatures struggle to heat larger pads like battery leads. Higher temperatures risk lifting pads off the PCB. Start at 350°C and adjust from there.
Use a small chisel or bevel tip (2-3mm) for most flight controller pads. A finer conical tip works for tiny whoop boards. Keep the tip clean and tinned throughout your session.
Step-by-Step: Soldering a Wire to a Pad
First, tin the wire. Strip 2mm of insulation, add flux, then touch iron and solder to the wire simultaneously. The solder wicks into the strands, creating a solid silver tip.
Next, tin the pad. Add flux to the pad, touch the iron for one second, then feed a small amount of solder. It should spread evenly in a thin dome.
Now join them. Hold the tinned wire against the tinned pad with tweezers. Touch the iron to the joint for one to two seconds. Both layers of solder melt together. Remove the iron while holding the wire still until the joint solidifies.
A good joint is shiny, concave, and covers the entire pad. If it looks dull or has a gap, reflow with fresh flux.
Common Mistakes to Avoid
Cold joints happen when the iron is not hot enough or you remove heat too fast. The solder looks grey and grainy. Always ensure the iron is at temperature before touching the joint.
Bridging occurs when too much solder spreads between adjacent pads. Use less solder and apply flux. If a bridge forms, reflow with flux and pull the excess away with solder wick.
Lifted pads result from excessive heat or force. Never press down on a pad. Let the heat do the work. If a pad lifts, scrape the trace and solder to the exposed copper underneath.
For more build techniques, see our FPV drone wiring guide and 5-inch freestyle build guide.
FAQ
Q: Do I need lead-free solder for FPV builds?
A: Most FPV builders prefer 60/40 tin-lead solder because it melts at a lower temperature and flows more easily. Lead-free solder requires higher temperatures that increase the risk of lifting pads.
Q: How long should I hold the iron on a pad?
A: One to three seconds maximum. If the solder has not flowed within that time, your iron may be too cold or the pad needs more flux. Prolonged heat damages the copper pad.
Q: Can I use the same iron for battery leads and signal wires?
A: Yes, but battery leads (10-12 AWG) need a larger tip and higher temperature (380°C) because thick wire acts as a heat sink. Signal wires (26-30 AWG) need a fine tip at 320°C.
Q: What is the easiest way to practise before building a drone?
A: Use a practice board or an old broken flight controller. Practise tinning wires, soldering to pads, and desoldering with wick. See our guide to essential FPV drone tools for the full toolkit.