Frequently asked questions about neodymium magnets

Short answers to the most frequently asked questions about neodymium magnets: strength, grade, temperature, rust, safety, electronics, mounting and applications, with links to the detailed articles.
By Magnetenspecialist
4 min read
Neodymium blokmagneet 25 x 8 x 3 mm

Short answers to the most frequently asked questions about neodymium magnets. Each question includes a link to the full article.

Material and strength

What is a neodymium magnet?

A permanent magnet made of neodymium, iron, and boron (NdFeB): the strongest type of magnet you can buy. See what is neodymium and where does it come from?

How strong is a neodymium magnet?

A disc magnet Ø10 x 3 mm holds approx. 2.1 kg, Ø20 x 5 mm approx. 7.4 kg and Ø40 x 20 mm approx. 49 kg. See how strong is a neodymium magnet?

What does N35, N42, N48 or N52 mean?

The quality: the number is the energy product in MGOe. N52 is 20–40% stronger than N35 of the same size. See what does N35, N42, N48 and N52 mean?

What is the difference with a ferrite magnet?

Neodymium is approximately 10 times stronger than ferrite of the same size, but is less heat-resistant and prone to rust. See neodymium, ferrite or samarium-cobalt?

Why does my magnet hold less than stated?

Due to paint, thin steel, a small distance or sideways load. See how is the holding force determined? and holding force, pulling force and working load.

How many magnets do I need?

Weight × safety factor (2–3 perpendicular, 5–10 on a vertical wall), divided by the holding force per magnet. See how many magnets do I need? and converting kg, Newtons and lbs.

Temperature, rust and lifespan

What temperature can a neodymium magnet withstand?

Standard up to approx. 80 °C (N50/N52: 60–70 °C). Special grades up to 200 °C and more. See magnet at high temperatures.

Do neodymium magnets rust?

Yes, without coating. See why do neodymium magnets rust? and which coating should you choose?

Can magnets be used outdoors?

Yes, with epoxy, plastic or rubber. See can magnets be used outdoors?

Does a magnet lose its strength?

Naturally, by less than 1% in 10 years. Only heat, rust, breakage or a strong opposing field make it weaker. See why do magnets lose their strength?

Safety and electronics

Are neodymium magnets dangerous?

Not during normal use, but beware of children swallowing them, pinching, splinters and pacemakers (minimum 15 cm distance). See are neodymium magnets dangerous? and magnets, children and pets.

Can a magnet damage my phone or bank card?

Not a phone; but it can damage a magnetic strip. Chips and contactless cards work fine. See magnets and electronics.

How do I separate strong magnets?

Slide sideways, do not pull straight. See how do you separate strong magnets?

Does a magnet bracelet work?

There is no convincing evidence that static magnets reduce complaints. See does magnet therapy work?

Where do I dispose of old magnets, and how do I ship them?

At the recycling centre as metal; ship with padding to the outside of the box. See disposing of or shipping magnets.

Choosing and mounting

Which magnet should I choose?

Start with the surface and the mounting. See which magnet should I choose? or the overview by shape.

How do I mount a magnet?

With a countersunk hole, two-component adhesive, an adhesive layer or a pot magnet with a wire. For a countersunk closure, choose two magnets (north against south) or a magnet with a steel counter ring. See how do you mount a magnet?

Does a magnet work through wood, glass or plastic?

Yes, but the force quickly drops off with thickness. See do magnets work through wood, glass and plastic?

Which metals are magnetic?

Iron, steel, nickel, cobalt and some stainless steel. Not: gold, silver, copper, brass, aluminium and zinc. See which metals are magnetic? and is stainless steel magnetic?

What is the difference between axial and diametrical magnetisation?

Poles on the flat sides or on the round side. See axial or diametrical?

How do I magnetise a screwdriver?

Stroke it 20–30 times in one direction with a strong magnet. See magnetising or demagnetising tools.

How do I prevent scratches from a magnet?

With a rubber-coated magnet or a rubber protective disc.

Can I have custom-made magnets?

Yes, with a delivery time of 6 to 8 weeks. We often have something suitable in stock. See custom-made magnets.

Applications

Ordering

How quickly will I receive my order?

Ordered and paid for before 16:00 on working days, it will be shipped the same working day if in stock. Free shipping within the Netherlands from €45.

Can I get advice?

Yes. Use the Magnet Advisor or contact us.