Magnets are one of the best third hands a soldering bench can have. A couple of strong neodymium discs on a steel plate will hold wires, boards, and connectors right where you want them, hands-free. The catch is that the iron making the joint is also the quickest way to ruin those magnets. Neodymium and heat do not get along. Two things to get right, then: using magnets to hold the work, and keeping the iron's heat away from them. Here is both.
Why magnets make a good soldering jig
A soldering joint needs three things held still at once: the two parts being joined and, usually, the solder or the iron. That is one hand too many. A magnetic setup fills the gap. Drop a steel plate on the bench, and strong neodymium magnets become repositionable anchors you can slide into place in a second and lift off just as fast.
Common setups that work well:
- Holding stranded wire flat against a pad while you tin it.
- Pinning a PCB or a small board to a steel work surface so it cannot skate around.
- Clamping two wires end to end for an inline splice.
- Anchoring connectors, terminals, and battery tabs at a fixed angle.
- Backing up magnetic helping-hands arms with a magnet foot instead of a clamp.
For most bench jigs, a strong disc or block magnet in the 6–12 mm range is the sweet spot: enough grip to hold parts against the tug of a wire, small enough to place precisely. A 6 mm × 2 mm N52 disc pulls about 1.58 lb, and a 10 mm × 3 mm N52 disc about 5.16 lb, so you can match the hold to the job. The full size-by-pull chart is on our magnet specifications page, and the super magnets collection covers the disc and block sizes that suit bench work.
The heat problem: why soldering fights neodymium
Neodymium is the strongest magnet you can buy, but it is also the most heat-sensitive of the common types. A standard N52 magnet is only rated to about 80°C (176°F) before it starts to lose strength. For every 1°C of rise, a neodymium magnet sheds roughly 0.1–0.2% of its energy product. Stay inside the rated range and most of that loss comes back when the magnet cools. Push past it and the loss turns permanent.
Now put that next to a soldering iron. A hand-soldering iron for lead-free work usually runs 300–350°C (572–662°F), with around 330°C (626°F) a common sweet spot. Lead-free solder melts near 217°C (423°F); older leaded solder melts near 183°C (361°F). Either way, the tip is many times hotter than a neodymium magnet can survive.
It gets worse at the top end. A neodymium magnet loses its magnetism completely at its Curie temperature, which lands around 310–400°C (590–752°F), depending on the alloy. That is the same neighborhood as a soldering iron tip. Touch a standard neodymium magnet directly with a 330°C (626°F) iron, or sit it against a joint while you work, and you are heating it to the point of no return. It will come away weaker, and sometimes dead.
Keeping your magnets alive while soldering
The fix is mostly about distance and time. The magnet's job is to hold cool metal a little way back from the heat, not to sit in it.
- Keep the magnet back from the joint. A few centimeters of clearance between the magnet and the spot you are heating is usually enough. Metal carries heat, but a short run of wire or a board edge sheds most of it before it reaches the magnet.
- Let the steel plate do the gripping, not the heat zone. Anchor the work to a steel surface away from where the iron lands, so the magnet never shares space with the tip.
- Never solder directly onto a neodymium magnet. The iron tip alone will overheat it, and the nickel-copper-nickel plating is not made to take solder.
- Work fast and let parts cool. Brief, momentary warmth a magnet can recover from. Sustained heat it cannot.
- Mind the residual heat. A just-soldered joint and the iron stand both stay hot. Keep magnets clear of both until things cool.
Used this way, a magnetic jig and a soldering iron coexist fine. The magnets hold; the heat stays at the joint.
When you need a magnet right at the hot zone
Sometimes the magnet has to be close to the heat, and standard neodymium will not survive it. Two options trade some pulling power for heat tolerance.
Samarium-cobalt (SmCo) is the heat specialist. Depending on the grade, SmCo holds up to a maximum operating temperature of 250–350°C (482–662°F), with a Curie temperature of 700–800°C (1292–1472°F). That is right in the working range of a soldering iron. SmCo pulls less than neodymium of the same size and costs more, but it keeps its strength where neodymium quits.
High-temperature neodymium grades sit between the two. The suffix on the grade tells you the ceiling: SH is rated to 150°C (302°F), UH to 180°C (356°F), EH to 200°C (392°F), and AH to 230°C (446°F). They outlast standard N-grades in a warm setting, but none of them shrug off a 330°C (626°F) tip pressed against them. For genuine contact with soldering heat, SmCo is the safer call.
We stock standard neodymium by default. If a job needs a high-temperature neodymium grade or samarium-cobalt, tell us the temperature you are designing for and we will quote the right grade.
Soldering a wire to a magnet
This comes up often. If you can avoid it, do not solder to the magnet itself: neodymium's plating resists solder, and the heat needed to make the joint will demagnetize it.
Better routes:
- Solder to a steel washer or cup the magnet sticks to. Make your electrical joint on the steel part, then let the magnet grip the steel. The magnet never sees the iron.
- Use a magnet with a fitting already attached rather than building the connection with heat.
- If it truly must be soldered directly, reach for samarium-cobalt and work as fast as the joint allows, accepting that even SmCo has limits.
What to reach for
- Bench jigs and helping hands: strong disc or block magnets, 6–12 mm, from the super magnets collection. Match the pull to the part using the chart on the specifications page.
- Anything near sustained heat: samarium-cobalt, or a high-temperature neodymium grade. Ask us for the grade that matches your temperature.
- Wire-to-magnet connections: solder to a steel washer the magnet holds, not to the magnet.
Soldering with magnets FAQ
Will a soldering iron demagnetize a magnet?
Yes, if it gets close enough. A standard neodymium magnet is rated to about 80°C (176°F) and loses its magnetism entirely around 310–400°C (590–752°F). A soldering iron runs 300–350°C (572–662°F), so direct contact or sustained closeness will permanently weaken it.
Can you solder directly onto a neodymium magnet?
It is not recommended. The heat demagnetizes the magnet and the nickel-copper-nickel plating is not made to take solder. Solder to a steel washer or cup the magnet attaches to instead.
How far should magnets be from the soldering joint?
A few centimeters of clearance is usually enough for a quick joint, since wire and board edges shed most of the heat before it reaches the magnet. Keep the magnet on cool metal, away from the tip.
What magnet survives soldering heat?
Samarium-cobalt holds up best, with a maximum operating temperature of 250–350°C (482–662°F). High-temperature neodymium grades (SH, UH, EH, AH) tolerate 150–230°C (302–446°F), better than standard neodymium but still below a soldering iron tip.