Soldering Iron for FPV Builds: Temps, Tips and Portable Irons

The right iron for FPV work comes down to a few specs and a few setpoints. This column covers what to look for, what temperature each joint needs, and how today's 140W USB-C irons hold up for field repairs.

By the FPV Drone Essentials editors · Build · Published November 2, 2026

Soldering on an FPV quad covers two very different kinds of joint. At one end are XT60 leads and ESC power pads, which carry heavy copper. At the other are flight controller signal pads, which are small and sit close to sensitive parts. An iron, tip and temperature that suit one end can be a poor match for the other.

This column does not rank products. It covers the specs that matter, gives a working temperature for each common FPV joint, and then looks at how the new class of high-power USB-C irons performs away from the bench.

The timing is relevant. Joshua Bardwell recently posted a YouTube video naming the ALIENTEK T90B as his ideal portable iron. That is a recommendation from a well-known builder, not a bench test. An independent bench review of the same iron is covered below, and it complicates the picture.

The four specs that matter

Wattage

Wattage sets how much heat the iron can push into a joint before the joint pulls the tip temperature down. Oscar Liang's FPV iron buyer's guide treats 30W as the minimum. It prefers 60W or more for heavy joints and wants a maximum temperature of at least 400°C.

The heavy joints are the reason for that 60W preference. Holybro rates an XT60 on 12 AWG wire at 30A continuous and 60A for bursts under a minute. To carry that current, the wire and connector need a lot of copper, and that copper soaks up heat fast.

Heat recovery

Recovery is how quickly the iron returns to its setpoint after the tip touches something cold. A spec sheet rarely states it, so it usually takes a bench test to see. The T90B review below includes one: the reviewer cooled the tip repeatedly with an air duster and watched how the iron responded.

Tip shape and size

Hakko's guidance is to size the tip to the joint, then choose the version of that size with the most thermal mass. A tip that is too small cannot deliver enough heat. A tip that is too large can damage the board or the part.

Hakko also points out that a lower setpoint, held for less time, cuts tip oxidation sharply and makes tips last longer. In practice this means you should fix a struggling XT60 joint with a bigger, heavier tip, not by turning the dial up.

Power input

For a bench station this is simple: it plugs into the wall. For a portable iron, the power source largely determines how the iron performs.

USB Power Delivery 3.1 added fixed voltages of 28V, 36V and 48V, which support 140W, 180W and 240W. The 28V/140W level is the one that lifts USB-C irons above the old 20V limit. Reaching it takes a PD 3.1 charger and an e-marked EPR (240W) cable. If either is missing, the iron falls back to lower power.

The iron's official rating is a separate question. Some irons run at 28V only unofficially, as the Pinecil section below shows, so check what the maker actually supports.

Working temperatures by joint

The setpoints below come from Oscar Liang's FPV soldering guide and assume 63/37 solder. They are one experienced builder's practice, not a standard. Other FPV sources put XT60 anywhere from 380°C to 450°C.

Treat these numbers as starting points. The right value also depends on tip mass, iron wattage, flux and solder alloy. It depends most of all on whether the display matches the real tip temperature, which is covered in the portable-iron section.

Solder alloy changes the numbers

Eutectic 63/37 tin-lead melts at a single point, 183°C (361°F). Some older FPV articles give a much higher figure, but 183°C is the correct one.

The common lead-free alloy SAC305 begins to melt at 217°C (423°F) and is fully liquid at 220°C (428°F), according to AIM's datasheet. Lead-free joints therefore need more heat. If you switch alloys, expect to run hotter than the setpoints above.

Battery leads sit at one end of the system, signal pads at the other. The Power Chain explains why the high-current joints deserve the most care. The Build Order shows where each joint falls in a typical build.

Portable USB-C irons for field repairs

A field iron needs to do two jobs: reflow a motor wire on a quad that clipped a gate, and replace a torn XT60 lead before the next pack. The second job is the hard one.

The older generation of TS100-era irons stops at 400°C by default. That falls short of the 450°C XT60 setpoint above. Newer 140W PD 3.1 irons such as the T90B list a maximum of 450°C, which covers that setpoint on paper, provided the supply can deliver. As the bench test below shows, the displayed and actual temperatures can drift apart at the top of the range.

ALIENTEK T90B

The Japanese distributor's listing gives these specs for the T90B:

• DC 9 to 28V input, with PD 3.1 and QC 3.0 support
• Heating power adjustable from about 18W to 140W
• 80 to 450°C temperature range
• About 3.5 seconds to melt solder at 140W
• 55 g listed weight
• Release date of 2025-09-10

The reviewer below measured the handpiece with tip, without cable, at 39.77 g.

The T90 family comes in three versions, split by cartridge type:

• The T90A uses fine T210 tips.
• The T90B uses general-purpose T245 tips.
• The T90C uses T65 tips.

The distributor's listing calls the T90B's tips T80P-compatible, while the manual and review say T245. Check which name your tip seller uses before ordering spares.

Gough Lui's August 2026 bench review tested one unit. It found a clear strength and several catches.

Strength

• Recovery is good. Under repeated air-duster blasts, the tip came back to temperature fast without overshooting and settled around 324 to 326°C.

Catches

• It needs at least 9V. Older 5V-only power banks and chargers will not run it.
• It needs real wattage. The reviewer suggests a supply of 60W or more. At 18 to 20W, anything beyond thin wires and small board work was frustrating.
• The display reads low. A 350°C setting measured about 330°C. At a 450°C setting the gap grew to about 34°C, so the tip did not actually reach 450°C at that setting. The error curves across the range, so one offset cannot correct it.
• The stock knife tip is marginal on heavy wire. It struggled with 2.5 mm² wire, which is about 13 AWG and close to typical XT60 lead gauge.
• The tip can float on ungrounded power. On a power bank or a two-prong supply, the tip can sit at a voltage, and the iron has no obvious earthing point. This is an ESD concern when you work on flight controllers and VTXs.

All of these findings come from one unit and one reviewer, so unit-to-unit variation is unknown. Even so, the pattern supports a general rule for any portable iron: Displayed temperature should not be treated as true tip temperature until you have checked it.

Pinecil V2

The Pinecil is often credited with 88W over USB-C. That figure is wrong. PINE64 rates the Pinecil V2 at 12 to 24V and 88W overall, but 88W is the rating for 24V through the DC5525 barrel jack.

The official USB-C spec is PD at 12 to 20V and 3A. That works out to roughly 50 to 64W, depending on tip resistance.

PINE64 says the Pinecil V2 also works with 28V PD 3.1 EPR chargers and certified 240W cables, but only unofficially. Its chart shows about 126W with the 6.2-ohm tip at 28V, compared with 64W at 20V PD. That is a large gain, but it falls outside the official rating.

Firmware also matters. The current stable IronOS v2.23, released August 31, 2025, does two things relevant here:

• It turns Bluetooth off by default. Older guides that show app pairing straight out of the box no longer match.
• It reworks the Pinecil V2's I2C bus to fix glitches in temperature regulation and the screen.

If your Pinecil holds temperature erratically, updating to v2.23 is a sensible first step.

Putting it together

For a portable setup, go through this checklist:

1. Match the charger to the iron. Use a PD 3.1 charger and an e-marked 240W cable for a 140W iron. A 5V-only power bank will not work.
2. Carry two tips. Bring a fine tip for pads and the heaviest tip that fits for XT60 leads.
3. Check the real tip temperature. Do this once at home, then adjust your presets to compensate.
4. Watch for ESD on battery power. Treat an iron running from a power bank as an ESD risk around your FC and VTX.
5. Set temperatures for your solder. If you use lead-free, go higher than the 63/37 numbers above.

The Tools and Using the Tools chapters of FPV Drone Essentials cover the rest of the bench kit and the handling technique that pairs with these settings. For a parts-level view of where each joint lives, see FPV Drone Components Explained.

Sources

• YouTube oEmbed metadata for Joshua Bardwell video jPXecdg2hcA
• Gough's Tech Zone – Review: ALIENTEK T90B 140W Smart USB-C Soldering Iron
• Switch Science – ALIENTEK T90B product page (Japanese distributor)
• USB-IF – USB Charger (USB Power Delivery)
• PINE64 – Pinecil Specifications
• PINE64 – Pinecil Power Supplies: Watts
• GitHub – Ralim/IronOS release V2.23
• Oscar Liang – A Beginner's Guide to Soldering for FPV Drones
• Oscar Liang – Soldering Tools 101: A Comprehensive Buyer's Guide for FPV Drone Pilots
• Hakko UK – Derek's Tech Tips, Issue 13
• AIM Solder – SAC305 Lead-Free Solder Alloy TDS (and Kester Alloy Temperature Chart for Sn63Pb37)
• Holybro Docs – Connector & Wire Rating

Facts checked against the sources above as of October 26, 2026. Drone rules and firmware change; check the current version before you rely on a detail.