# FPV Drone Soldering Guide: Tools, Techniques, and Common Mistakes to Avoid
Soldering is the fundamental building skill of FPV. Every wire, every motor, every receiver — it all comes down to a good solder joint. A cold joint might hold for a few flights, but it will fail at the worst possible moment. This guide covers the tools, techniques, and pitfalls that separate reliable builds from ticking time bombs.
## Essential Soldering Tools
| Tool | Recommended Spec | Budget Option | Why It Matters |
|—|—|—|—|
| Soldering Iron | 65W+, temp-controlled (TS100, Pinecil, Hakko FX-888D) | $15 60W fixed-temp iron | Temperature control prevents pad lifting |
| Tip | Chisel tip 2.4 mm (TS-D24 or equivalent) | Conical tip (less ideal) | Chisel tips transfer heat faster |
| Solder | 63/37 SnPb rosin-core, 0.5-0.8 mm diameter | 60/40 SnPb | 63/37 is eutectic — solidifies instantly |
| Flux | No-clean rosin flux pen or paste (MG Chemicals 8341) | Rosin-core solder (built-in) | Extra flux makes impossible joints possible |
| Brass Sponge | Brass wool tip cleaner | Wet sponge | Brass does not thermally shock the tip |
| Helping Hands | Adjustable arms with alligator clips | Blue-tack or tape | Holds wires steady while you solder |
| Magnification | Head-mounted magnifier or USB microscope | Phone camera zoom | Inspect joints for bridges and cold spots |
### Soldering Iron Temperature Guide
| Joint Type | Temperature |
|—|—|
| Small signal pads (UARTs, receiver wires) | 320-350 °C (608-662 °F) |
| ESC power leads (12-16 AWG) | 380-400 °C (716-752 °F) |
| Battery leads / XT60 (10-12 AWG) | 400-420 °C (752-788 °F) |
| Motor wires to ESC pads | 350-380 °C (662-716 °F) |
## The Perfect Solder Joint: Step by Step
### Step 1: Tin the Tip
A dry tip does not transfer heat. Apply a small amount of solder to the iron tip, then wipe on the brass sponge. The tip should be shiny, not dull or black. Re-tin every few joints.
### Step 2: Tin the Pad
Apply the iron to the pad for 1-2 seconds, then feed solder directly onto the pad (not the iron). The solder should flow smoothly and form a shiny dome. Remove the iron. A properly tinned pad looks like a smooth silver pillow.
### Step 3: Tin the Wire
Strip 2-3 mm of insulation. Twist the strands together. Apply flux to the exposed wire. Touch the iron to one side and feed solder from the opposite side until it wicks into the strands. The wire should be fully saturated but not dripping.
### Step 4: Join Wire to Pad
Position the tinned wire on the tinned pad. Apply the iron so it touches **both** the wire and the pad simultaneously. Hold for 1-2 seconds until the solder on both flows together, then remove the iron. Do NOT move the wire until the joint solidifies (1-2 seconds for 63/37).
### Step 5: Inspect
A good solder joint is **shiny, smooth, and concave** (filleting from pad to wire). It should not be:
– **Dull or grainy** — cold joint
– **Ball-shaped** — insufficient heat, wire not wetted
– **Spiky** — iron removed too fast or too hot
– **Bridging** to adjacent pad — solder touching another pad
## Top 7 Soldering Mistakes (and How to Fix Them)
| Mistake | Consequence | Fix |
|—|—|—|
| Too little heat | Cold joint, wire pulls off | Increase temp or use larger tip |
| Too much heat | Lifted pad, damaged PCB | Reduce temp, work faster |
| No flux | Solder balls up, won’t flow | Apply external flux |
| Dirty tip | Poor heat transfer, frustration | Clean with brass sponge, re-tin |
| Moving before solidification | Fractured joint | Hold wire still for 2 seconds after removing iron |
| Insufficient tinning | Joint looks OK but fails later | Tin BOTH wire and pad before joining |
| Using lead-free solder on small pads | Terrible wetting, cold joints | Use 63/37 SnPb for everything (RoHS exempt for hobby) |
## Special Techniques
### Soldering XT60 Connectors
XT60 cups are large and sink a lot of heat. Crank your iron to 420 °C, pre-tin the cup, tin your 12 AWG wire heavily, then heat the cup from the side while inserting the wire. Use a XT60 holder (3D printed or helping hands) so the connector does not move.
### Soldering Motor Wires
Motor wires have enamel coating that MUST be removed. Pre-tin your ESC pad with a generous blob, then press the motor wire into the molten solder with the iron tip. The heat burns off the enamel. Add more solder as needed. Check continuity after cooling.
### Wire-to-Wire Splices
For receiver antennas or thin signal wires: strip both ends, twist together, apply flux, and solder. Cover with heat shrink. For power wires, use a “Western Union” splice (wires wrapped around each other) for mechanical strength before soldering.
## Safety Note
Always solder in a well-ventilated area. Rosin flux fumes are an irritant. Consider a small fume extractor or at minimum a fan blowing fumes away from your face. Keep a fire extinguisher nearby — solder splashes onto LiPos are extremely dangerous.
## Recommended Soldering Kit
A reliable soldering setup is the best investment you will make. The **Pinecil V2** and **TS100** soldering irons — along with quality solder and flux kits — are available at [uavmodel.com](https://uavmodel.com). These portable irons heat up in seconds, run off a LiPo in the field, and offer precise temperature control that budget irons simply cannot match.
## Watch: FPV Soldering Tutorial for Beginners
## Frequently Asked Questions
**Q: Should I use leaded or lead-free solder for FPV?**
Use leaded (63/37 SnPb). Lead-free solder requires higher temperatures, wets poorly on small pads, and produces dull joints that are hard to inspect. The hobby exemption from RoHS makes this the standard choice.
**Q: How do I fix a lifted pad?**
Locate the trace that the pad connected to and scrape off the solder mask with a hobby knife to expose bare copper. Solder a thin wire from the component lead to the exposed trace. Alternatively, find the alternate pad (many FCs have multiple pads for the same signal) listed in the pinout diagram.
**Q: Why does my solder ball up and refuse to stick?**
This is almost always a flux issue. The pad or wire has oxidized. Apply fresh flux, heat the pad, and feed solder. If it still balls up, lightly scuff the pad with fine-grit sandpaper or a fiberglass scratch pen to expose fresh copper, then flux and solder immediately.
**Q: How long should my iron tip last?**
A quality tip used with proper care (always tinned, cleaned with brass not steel wool) lasts 6-12 months of regular use. If the tip develops pits, turns black and refuses to wet, or has eroded past the plating — replace it. A worn tip is the #1 cause of soldering frustration.