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

Short answers to the most frequently asked questions about neodymium magnets. Each question links to the detailed 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 Ø10 x 3 mm disc magnet holds approx. 1.6 kg, Ø20 x 5 mm approx. 4.9 kg and Ø40 x 20 mm approx. 49 kg. See how strong is a neodymium magnet?

What do N35, N42, N48 or N52 mean?

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

What is the difference with a ferrite magnet?

At the same size neodymium is about 10 times as strong, but less heat-resistant and prone to rust. See neodymium, ferrite or samarium cobalt?

Why does my magnet hold less than stated?

Because of paint, thin steel, a small distance or sideways loading. See how is holding force determined? and holding force, pull 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, Newton 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 beyond. See magnets at high temperatures.

Do neodymium magnets rust?

Yes, without a coating they do. 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?

By itself 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 in normal use, but watch out for swallowing by children, pinching, splinters and pacemakers (at least 15 cm distance). See are neodymium magnets dangerous? and magnets, children and pets.

Can a magnet damage my phone or bank card?

A phone no; a magnetic stripe yes. Chip and contactless keep working. See magnets and electronics.

How do I separate strong magnets?

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

Does a magnetic 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 them with distance 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 per shape.

How do I fix a magnet?

With a countersunk hole, two-component glue, an adhesive layer or a pot magnet with thread. See how do you mount a magnet?

Does a magnet work through wood, glass or plastic?

Yes, but the force drops quickly 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 axially and diametrically magnetised?

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

How do I make a screwdriver magnetic?

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 pad.

Can I have custom magnets made?

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

Applications

Ordering

How quickly will I receive my order?

Ordered and paid on working days before 16:00, items in stock are shipped the same working day. Free shipping within the Netherlands from €45.

Can I get advice?

Yes. Use the Magnet Advisor or contact us.