FAQ

A magnet is a material that can produce a magnetic field. To be classified as a magnet, the object must be capable of:

• Attracting materials such as iron, nickel, cobalt and certain steels and alloys
• Exerting an attractive or repulsive force on other magnets as per specific polar orientation i.e. North or South pole (remember the age-old adage (opposites attract!)
• Having an effect on electrical conductors which move in relation with the magnet
• Having an effect on electrically charged particles traveling in free space

Typical permanent magnets are made of ferromagnetic materials which generally include the elements like Iron, Nickel and Cobalt, their alloys and often some rare-earth metal compounds. A property of these ferromagnetic materials is that they possess a very weak, but naturally occurring magnetic field that is created by the electrons that surround the nuclei of their atoms. Now these atoms are present in groups called domains which, within themselves, act like permanent magnets with a North and South pole of their own. In a magnet, there are multiple such domains but their orientations cancel each other's magnetism out i.e. their corresponding North and South poles interact to negate each other's magnetic field. Keeping this in mind, a simple inference we can make is that these ferromagnetic entities will get magnetised if their domains stop cancelling each other out and instead point towards a single direction leading to the generation of a single magnetic field. This is achieved by heating a ferromagnetic material at incredibly high temperatures and exposing them to a very strong external magnetic field at the same time. Upon doing so, all the domains would line up as per the external field and when the material is then cooled down, the domains get locked into their aligned positions. After the external magnetic field is removed, the domains will remain aligned thereby creating a very strong permanent magnet.

Quite similar to identifying the poles of the Earth, the best way is to use a compass. The only difference being, the end of the needle that normally points towards the North Pole of the Earth would actually be the South Pole of the magnet. Another simple way is to use an existing magnet with its poles marked. In which case, the North Pole of the marked magnet will point to the South Pole of your unmarked magnet. Neither of the two poles is stronger than the other. They are both equally as strong in order to create a uniform magnetic field i.e. a field with uniform magnetic field strength distribution.

There are 3 types of magnets: permanent magnets, temporary magnets and electromagnets.

• Permanent magnets: Emit magnetic fields without the need for any external source of power. Once magnetized, they hold on to their magnetic properties.
• Temporary magnets: Behave as magnets while attached to or close to something that emits a magnetic field but lose this characteristic when the source of the magnetic field is removed.
• Electromagnets: Require electricity in order to behave as a magnet. The magnetic field disappears when the electric current is turned off. Typically, electromagnets are used in conjunction with a solenoid and a ferromagnetic material (which we call the iron core) placed in it gets magnetized or demagnetized with the electric current.
• Electro-Permanent Magnets: A modern and hybrid system that only requires a momentary pulse of electricity in order to become a permanent magnet and remains so even if the source of electricity is switched off. Similarly, a pulse of electricity is required to discharge the magnetism. The magnetic field disappears when the electric current is turned off. Electro-permanent magnets are constructed with a solenoid and two types of permanent magnets. A low coercivity permanent magnet is used as a core material and a high coercivity permanent magnet is used as a flux multiplication packing placed around the core.

Magnets can only attract materials that can be magnetised and these are the ferromagnetic material which include Iron, Nickel, Cobalt and their alloys.

Here's some good news - magnets can retain their magnetism essentially forever if used and stored appropriately, i.e. away from factors that adversely affect magnetism. Some of these factors include:

• Heat
• Radiation
• Close proximity to very strong electric currents
• Close proximity to other magnetics of like polarity
• High humidity may corrode neo magnets (unless if they have protective coating)

However, modern magnet materials do lose a very small fraction of their magnetism over time. For example, Samarium Cobalt materials may lose less than 1% of their magnetism over ten years. Not too bad, is it?

Absolutely. Magnets can be re-magnetized to their original strength, unless if your magnet has been damaged by extreme heat which you might want to avoid! However, industrial grade super powerful magnets cannot be re-magnetized easily in your home or lab, requiring a high current magnetizer.

An alloy of Neodymium, Iron and Boron (also known as NdFeB, NiB or Neomagnet) creates very strong magnets. Specifically, till date, this alloy (Nd₂Fe₁₄B) makes the strongest permanent magnets in the world.

You will come across many different terms when it comes to measuring magnet strength and this just calls for more technicalities here. Three of the most commonly used terms are Pull, Gauss and Hysteresis:

• Pull refers to how much force is needed to pull the magnet off of a steel surface. It is measured in kg, using a Pull-tester.
• Gauss is a measure of magnetic induction. Simply put, a magnet's Gauss measurement represents the number of magnetic field lines per square centimeter, emitted by a magnet. The higher the value, the more lines of magnetism emitted by a magnet. Gauss is measured using a Gaussmeter or flux meter and gives a reading of the number of lines of magnetism in every cm2 (1 Gauss = 1 line of magnetism in 1 cm2), also known as flux density.
• However, note that the Gauss rating alone doesn't give a full picture of a magnet's strength. Apart from the material, the geometry of the magnet also has an effect on its Gauss value. For the same surface Gauss value, a larger magnet will have a much stronger pull force than a smaller one. What this means is that sometimes a small magnet may have a higher surface Gauss but will be able to support less weight than a larger magnet with a lower surface Gauss.
• Lastly, hysteresis simply refers to a delayed response to an applied stimulus. This stimulus could a magnetic field with a delayed magnetization or flux density. A hysteresis graph can be created by repeated magnetization and demagnetization within a closed-circuit situation and plotting a corresponding induced magnetic flux density vs magnetizing force graph (BH). The stronger permanent magnets would be made of materials that have a larger area within this hysteresis loop graph.

Yes. The basic idea is that the strength of a magnetic field reduces almost exponentially with increasing distance. If you want to get a little bit deeper into the physics, an estimate of magnetic field strength can be made for a circular magnet with a radius R and Length L, the field at the centerline of the magnet a distance x from the surface using the following formula (where Br is the Residual Induction of the material):

There's strength in numbers! Using two identical magnets together would be the same as having one large magnet of their combined size, essentially doubling the magnet's strength and pull. However, an optimum level of working is obtained once the length of the magnet exceeds the diameter of the magnet. Any further additions to magnetic length will provide only small, rather negligible, increases in performance.

Magnets are categorized by three main characteristics:

• Residual Induction (given the symbol Br and measured in Gauss). This is an indication of how strong the magnet is capable of being.
• Coercive Force (given the symbol Hc and measured in Oersteds). This is an indication of how difficult it is to demagnetize the magnet.
• Maximum Energy Product (given the symbol BHmax and measured in Gauss-Oersteds). This is an indication of what volume of magnet material is required to project a given level of magnetic flux.

The specified pull force may not be achieved for all magnets in real world conditions simply because the specifications are obtained by testing in labs under controlled conditions. There are multiple factors that could lead to a reduction in the effective pull force. Some of these factors include:

• Uneven contact with the metal surface
• Pulling in a direction that is not perpendicular to the steel material
• Attaching to metal that is thinner than desired
• Presence of surface coatings

Flux Density of the magnetic material is directly related to the Pull Force per cm² of the magnets that are used. The Pull Force number takes into account the size and shape of the magnet along with the flux rating of the material from which it is made.

The highest temperature at which a magnet can be effectively used, largely depends on the 'permeance coefficient' - a function of the circuit the magnet is operating in. The higher the permeance coefficient (the more 'closed' the circuit), the higher the temperature at which the magnet can be operated without becoming severely demagnetized. Shown here are approximate maximum operating temperatures for the various classes of magnet material. Its best to avoid reaching these temperatures for these specific materials.

To efficiently order magnets, you need to have a good idea of what you want to accomplish. Here are a few things to keep in mind:

• What is the nature of the intended application (e.g. holding, moving, lifting, etc.)?
• What is the desired shape of the magnet (e.g. disc, ring, rectangle, etc.)?
• What is the desired size (diameter, length, width, height, etc.)?
• Tolerances - what variation in dimensions is allowed?
• What conditions will the magnet be used in (e.g. elevated temperatures, humidity, outside, inside etc.)?
• What is the required strength of the magnet (e.g. in terms of Gauss, pounds of holding force, etc.)?
• Cost - what is your budget? This will eliminate certain materials from consideration.
• Quantity - how much do you need?

Yes, but only certain magnets. Generally, magnets are extremely brittle and it is best to derive the required size at the outset rather than to try and machine a larger magnet down to size. Flexible magnets can be cut down to size or drilled through. Neodymium magnets are the strongest magnets in the world they can be machined, but we recommend only experienced machinists perform this task (we elaborate on this further in the FAQ section on Neodymium magnets below. Check it out if you're interested!)

A magnetic field cannot be blocked, it can only be redirected. For redirecting, the elements must be able to interact with the field i.e. get magnetized, hence the only elements that make the cut are the ferromagnetic materials. This includes Iron, Nickel and Cobalt and their associated compounds.

However, it may be noted that the degree of redirection is directly proportional to the magnetic permeability of the material. The most efficient shielding material is the 80 Nickel family, followed by the 50 Nickel family. An example of such a high permeability nickel-iron alloy is 'mu-metal' which is quite effectively used to redirect the magnetic field.

Though magnets seem to be quite fun things to have around, care should be taken when handling and storing them. Here are some tips for the same:

• Always be careful! Magnets can snap together and injure personnel or damage themselves.
• Store magnets in closed containers, so that they don't attract metal debris.
• If several magnets are being stored, they should be stored in attracting positions.
• Alnico magnets should be stored with "keepers" (iron or magnetic steel plates that connect the poles of the magnet) since they can easily become demagnetized.
• Magnets should be kept away from pacemakers!
• Just to play it safe, keep magnets away from magnetic media - such as credit cards and computer monitors.

You may use mechanical means or simple adhesive means. Most commonly though, adhesives are used for securing magnets. Special care must be taken for the type of adhesives being used as for instance; uneven surfaces call for adhesives with more "body" to conform to the irregularities.

Specifically, hot glues have been found to work well for adhering magnets to ceramics, wood, cloth, and other materials. For magnets being adhered to metal, 'super-glues' can be used very effectively. We can supply Flexible magnets with an adhesive already attached to the magnet: all you need to do is to peel off the liner and attach to your product. Do note that for all of the above to be applicable, it is pretty important to ensure all surfaces being bonded are clean and dry before bonding.

Using a two-part epoxy adhesive has been known to work best for this scenario. We recommend Araldite Rapid or Loctite Industrial strength Adhesive both of which have a similar track record on reliability and speed with a setting time of about 5 minutes.

Most fridge magnets are made of either flexible rubber or ferrite magnets on the back. This is referring to the general ones you purchase off the regular souvenir stores. While they are not as strong as neodymium magnets, they provide great value for money and can conveniently hold the lightweight items you would normally expect fridge magnets to withstand. In addition, if we may so ourselves, they make for a wonderful decoration that would add to the excitement one generally has when approaching the fridge.

While we do not have a minimum order quantity, we do specify a minimum order value of US$15 to checkout from our store. Every shipment of magnets require special packing and whether packing for a quantity of 1 or 2000, the amount care taken in packaging is quite similar. It does not make sense for us to expend that effort unless there is a minimum value for the service.

It's alright if you change your mind. Supreme Magnets accepts returns on all magnets in original and resalable condition within 30 days of purchase, subject to terms and conditions. Please see our Returns Policy for details regarding returns and refunds.

Our main office facility and warehouse are located in a cozy and quiet industrial neighborhood in the western part of Singapore, quite easily accessible from everywhere. If you live nearby, feel free to walk-in or pick-up your purchase from our office. Otherwise, you can browse through our website catalogue and directly order from our plethora of online collection.

Our address is at 196 Pandan Loop, #02-11 Pantech Biz Hub, Singapore 128384.

No, we don't have any local distributors for our raw magnets. We do however encounter many cases of resellers buying off our store and selling to their customers, because we are one of the cheapest, while at the same time, being the best! However, you can purchase our products online through our website, by email, phone, or fax. We're just a click away!

This option is available only for customers in Singapore, who choose to self-collect their orders. Currently, we are unable to arrange Cash or Cheque collection for deliveries by Registered Post or local courier. Please see our Returns Policy for more details.

This depends on the shipping method and which part of the world you are at. Local delivery would take around 1-2 days, while Singpost Surface Parcel (by Sea) might take up to 4 weeks. DHL/FedEx for overseas shipments can take up to 4-5 days max.

We can deliver in any part of the world accessible to snail mail and the friendly Courier man! Please visit our website's Shipping Information and select a delivery option suitable for your location. Our preferred shipping carrier is Singapore Post by registered air mail, air parcel or local mail.

However, during checkout we offer you the option of Singapore Post or express courier (slightly more expensive) for you to choose. The indicative price is displayed alongside your option so you may choose accordingly.

There are very specific guidelines for the shipping of magnets by air while no such restrictions exist on shipping your magnets by ground. According to IATA's Dangerous Goods Regulation Guide, a magnetized material is considered dangerous for air transport if it has a magnetic field strength of 0.159 A/m (0.002 gauss) or more at a distance of 2.1 m (7 ft) from any point on the surface of the assembled package.

While we do understand your concern, our shipping policies have to comply with the safety guidelines of various governments and the different freight carriers, especially is they are being shipped by air. If you insist to airmail your magnets and they are withheld at your country's customs, we are unfortunately not liable.

Absolutely! Feel free to contact us with any special requests.

Monopole magnets do not exist. All magnets need to consist of two poles to create a surrounding magnetic field and individual poles cannot be isolated. It will create new physics if magnetic monopoles were ever to be discovered!

This is still possible with the ring-shaped magnets. and are generally referred to as being 'radially magnetized'. However, this feat is simply not possible with disc, cylinder, and sphere shaped magnets.

This is because we don't rely on the inaccurate formulae even though they would've made the job a lot simpler. Instead, our engineers have worked out a unique calculation method, far more accurate than any formulae as it utilizes several test cases and has been derived after long hours in the laboratory. The basic test involved the plates being pulled apart until the magnet disconnects from one of the plates. The peak value of the applied force is recorded as the "pull force". Do note though, if using steel that is thinner, coated, or has an uneven or rusty surface, the effective pull force may be different than recorded in our lab.

You ask for it and you shall have it. We do supply the BH curves for all our magnets upon our customers' request.

Neodymium is a member of the "rare earth" elements on the periodic table. Its magnets are actually the strongest of the rare earth magnets and are the strongest permanent magnets in the world! Neodymium magnets are composed of - you guessed it! neodymium, but also contain iron and boron. They are made by compressing a powdered mixture of the three elements under great pressure into moulds. This material is then sintered (heated under a vacuum), cooled, and ground or sliced into the desired shape. Coatings may also be applied if required. Finally, the blank magnet's are magnetized by exposing them to a very powerful magnetic field in excess of 30 KOe.

Just about anything under the sun! Some of the common usages seen today are: 

• The IT Industry uses Neo-magnets in hard disc drives, video and audio systems of television, mobile phones
• They are commonly used in magnetic separators, filters, ionizers, in production of on–off buttons, safety sector and security systems
• Grease filter producers use neodymium magnets in metal separators to more effectively filter out iron powder in oil
• Additionally, they are beneficial in covering machines, cars, etc. with awnings and in the production of magnetic tool belts
• They are also used in jewellery clips, identification badges and in the production of baby strollers that are attached to carriers via magnets
• The health sector is another field where neodymium magnets are incorporated in medical devices for example in magnetic resonance imaging devices to diagnose and treat chronic pain syndrome, arthritis.
• NASA uses neodymium magnets to maintain the muscle tone of astronauts during space flights.

Yes, there are limitations to the manufacturing size, as listed below:

• Approx. 7.5 cm (3") maximum in magnetized direction
• Approx. 15 cm (6") maximum diameter for discs and rings
• Approx. 20 cm (8") maximum length and width for blocks
• Approx. 0.8 mm minimum thickness
• Approx. 1.6 mm minimum outer diameter
• Approx. 1.6 mm minimum diameter for any hole

Neomagnets are quite strong permanent magnets and hence need to be stored carefully.

• They should be stored in a low humidity and mild temperature environment
• To prevent them from attracting any nearby debris, they should be kept in closed and clean containers.
• They should not be stored near any electronic equipment or magnetic storage devices.

Barely. Neodymium magnets are the strongest and most permanent magnets known to man. They lose less than 1% of their magnetic strength over 10 years as long as they are not damaged by extreme heat or physical wear and tear. That's barely enough for you to notice unless if you have very sensitive measuring equipment!

The material that these magnets are made of Neodymium, Iron and Boron and are very hard and brittle. Machining it would be difficult at best. The hardness of the material is a whopping RC46 on the Rockwell "C" scale, which is harder than most drills and tooling, so these tools would likely heat up and become damaged if used on the magnets.

Diamond tooling, EDM (Electrostatic Discharge Machines), and abrasives are the preferred methods. We suggest that the machining of neodymium magnets should only be done by experienced machinists who are familiar with the risks involved: for starters, the heat generated during machining can demagnetize the magnet and cause it to catch fire. Machining also produces dry powder, which is very flammable, so great care must be taken to avoid combustion of this material.

Once a magnet is fully magnetized, it is saturated and cannot be made any stronger. If it helps, you can stack magnets together and this would be the same as using a larger and stronger magnet.

Until a certain range they are good to go. But once we hit their Maximum Operating Point (80°C) we start losing a fraction of the magnet’s strength, and this is especially the case for Standard N grades. Now, if these magnets are heated beyond their Curie temperature, they will lose ALL their magnetic properties. These operating and Curie temperatures are material properties, and they differ even between the various grades of Neodymium itself.

Please don't try that! The heat would demagnetize the magnet, and might also cause it to catch fire and pose a safety risk.

We normally measure the surface field density, aka the magnetic field density, at the surface of a magnet using a Gaussmeter. This value is tested and specified for each of our stock magnets. This is the most practical measurement as compared to other readings such as the Residual Flux Density (BrMax) (which actually estimates the strength inside a magnet where we probably will never find ourselves at).

Yes, our magnets are fully RoHS compliant, meeting the European Parliament Directive entitled "Restrictions on the use Of Hazardous Substances" (RoHS). This Directive prohibits the use of the following elements in electrical/electronic equipment sold after 7/1/2006: cadmium (Cd), lead (Pb), mercury (Hg), hexavalent chromium (Cr (VI)), polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs).

The maximum operating temperature is the maximum temperature the magnet may be continuously subjected to, with a slight loss of magnetic strength. The Curie Temperature is the temperature at which the magnet will become completely demagnetized. At temperatures between these two points, a magnet will permanently lose a portion of its magnetic strength. The loss will be greater the closer to the Curie Temperature it is heated.

The maximum strength up to which a magnet can be magnetized is represented by its grade or N Value. This value actually refers to the Maximum Energy Product expressed in the units of millions of Gauss Oersted (MGOe). Generally speaking, the higher the grade, the stronger the magnet.

As a general rule of thumb, a peak field of between 2 and 2.5 times the intrinsic coercivity is required to fully saturate a magnet. For standard neodymium magnets, the field required is minimum of 24 KOe, with 30 KOe being the standard.

Coatings are chosen based on the user's preference or on the intended application of the magnet. They don't affect the magnet's strength, but can often protect it, for e.g. from corrosion. The most common material used for plating neodymium magnets is Nickel, which is used in conjunction with copper as a triple nickel-copper-nickel plating. Not only does it give a polished silver finish, but it also provides good protection from corrosion. You may have also seen black nickel used as a coating and this has a shiny black appearance and is a bit more resistant to corrosion than regular nickel.

Another common plating material is Zinc. Zinc provides a dull grey/bluish finish and is more susceptible to corrosion than Nickel. It can sometimes leave behind a black residue on the items it comes in contact with. Epoxy, another coating material, is a plastic coating which is fully resistant to corrosion but is the least durable of the common coatings. Gold plating can also be used; it has similar characteristics as nickel plating but is much fancier with its golden finish!

The material Neo magnets are made of contains Iron, which oxidises easily if exposed to moisture. You must have observed how even normal humidity can rust your Iron tools and wires. Plating or coating the magnets protects the Iron from rusting or corroding, extending the life of the magnet.

All paints that are formulated for use on metal surfaces can be used on nickel plating. We find that spray-on paint works best.

These materials don't "weaken" the magnet. It is just that a layer of plastic or rubber creates a large distance between the magnet and metal surface which reduces the pull force.

With a total thickness of about 17-20 µm, the nickel plating is actually a triple plating of Nickel (Ni)-Copper (Cu)-Nickel (Ni). Each layer has a rough thickness of about 5-6 µm for the Nickel layers and 7-8 µm for the Copper layer.

Due to the constant fear of oxidisation of the iron in the NdFeB material, unplated magnets are not stocked. However, these can be supplied as custom order items. Feel free to write in to us if you want to place your order.

There are no known health concerns with exposure to permanent magnetic fields. However, precautions must be taken when using these magnets around children. Magnets can be very dangerous if swallowed or if they trap a child's fingers. We aren't medical professionals; hence our best piece of advice will be to please consult your physician for any medical risks you may face with regards to magnets.

Magnets can cause pacemakers to operate in a mode that does not respond to the user's own cardiac rhythm and should therefore not be placed in close proximity to the pacemaker. Please consult your doctor for further information.

Strong magnets such as neodymium magnets can damage certain magnetic media, such as credit cards, video tapes, magnetic ID cards, etc when placed in direct contact with any of these items. They can also damage televisions, computer monitors and other CRT displays, and should therefore not be very near these appliances.

The same isn't true with hard drives or your smartphone memories as every hard drive already contains powerful neo magnets while phones contain small magnets within them, so one moving around outside the case will not affect their stored data. Similarly, small magnets do not damage electronics.

Magnets also do not harm appliances such as refrigerators, stoves, ovens and microwaves.

It really depends on the application of your product, the size of the magnet(s), how the magnet is used, and where the magnet is located within the product. We recommend providing any warnings that you think may be an issue.

You can separate small to medium sized magnets by sliding them off each other using your hands. For medium to large magnets, though, this technique won't be feasible. For these, you can take the assistance of the corner of a table and use brute force to slide the magnets off each other. For very large magnets (generally 2" and larger) neither of the techniques can be used; instead, we use a specially made magnet separating jig to separate them. Write to us for details and we shall be happy to furnish more information.

Adhesive tape should do the trick! It is the best way to clean magnets.

An easy way to protect your magnets is to wrap them with a few layers of electrical tape. This would protect them from most damage from collisions with hard surfaces. Another way to protect your magnets from damage due to impact or corrosion, is to give them a rubberized coating. We find that this works great to protect magnets from wear and tear.