Who’s afraid of the iron?

Hotter than a pizza oven: it burns in less than a second. If it happens, don’t panic. Do this:

Cool running water for 20 minutes. Yes, really 20.

Take off rings and watches before it swells.

After cooling: burn gel or spray from the first-aid kit, then cling film.

Every time, even if it seems tiny. You won’t be in trouble.

Know where they are before you switch the iron on.

Bigger than your palm, on the face or hands, or big blisters.

ice, butter or toothpaste · popping blisters · catching a falling iron, let it fall

The tip is hotter than any kitchen oven: around 350–400 °C. Do this first, every time.

Solder and flux can spit.

The smoke is flux. Don’t breathe it.

Every time you let go. Hold the handle, never the metal.

After soldering. No food or drinks at the bench.

And let it cool before you pack it away.

No LiPo plugged in while you solder.

Heat both at once.

Not onto the iron. It melts on the hot metal.

Solder flows towards the heat.

Hold still 2–3 seconds while it sets.

Never carry a drop of solder to the joint on the iron. The flux burns off and it won’t stick.

On drones we mostly solder a wire onto a flat pad. Tin both first, then they join in a second.

A little dome of solder on the pad.

Strip 2–3 mm, twist, soak it with solder.

Wire on the pad, touch with the iron. Both melt together.

Shiny, smooth, and the wire doesn’t move when you tug it gently.

A hot iron for a short time beats a cool iron for a long time. Long heating cooks the board and can lift pads.

flight controller, VTX, receiver · small pads

on the ESC · medium pads

big pads, thick wire

2–3 seconds per joint. Taking longer? Use a bigger tip and more flux, not more time. Starting points for leaded 63/37 solder; lead-free needs about 20–30 °C more.

Shiny little volcano = good. Anything else: reheat, add flux, try again.

Shiny and smooth, a little volcano.

Dull and grainy. It moved, or the iron was too cool.

A ball on top. It never really stuck.

Strands showing. Weak, it will crack.

Joins two pads: a short circuit!

Five checks. Every build, every repair. This is how you never see the magic smoke.

No blobs, no bridges, no stray bits of solder or wire.

Wipe the flux off with isopropyl alcohol, especially between + and –.

Multimeter on continuity between + and –. It must NOT beep.

Check the polarity on every power lead. Twice.

The first power-up goes through a smoke stopper, not straight from the battery.

Soldering is gluing metal with melted metal: the iron heats the parts, the parts melt the solder, and a good joint is a shiny little volcano.

Glasses on. Iron back in its stand every time you let go.

Tin both first, then join them in a second.

Hot and quick: 2–3 seconds per joint.

Shiny little volcano = good joint.

Beep test before the first battery.