Magnetic Mounting Systems for Museums and Cultural Institutions Receives Major Review

Since the publication of Gwen's book, Magnetic Mounting Systems for Museums and Cultural Institutions, early last year, more than 350 copies have sold worldwide, including to 26 countries in addition to the US on 6 of the 7 continents. Among the purchasers are 145 museums and galleries, and 69 libraries. The book was also one of the recipients of the 2019 Awards for Excellence from the Greater Hudson Heritage Network.

2019 GHHN Award for Excellence
(Photo Credit: K.Sclafani, GHHN)

In 2019, Gwen spoke to six groups in the U.S., Canada, and Europe about magnetic systems, advocating for their use in a variety of applications.

Gwen presenting at an International Conference

In her review of Gwen's book, conservator Kloe Rumsey wrote in the December 2019 issue of News in Conservation,

"A book dedicated to the use of magnets for the mounting and display of museum objects has been eagerly awaited by the global conservation community for years....There has been significant buzz in the profession since we began to hear news of a book, and as we cross our collective fingers that it's as good as we want it to be, I'm happy to say that I think it is."

Rumsey calls out Gwen's attention to describing the scientific details of magnets, defining terms and theories within the body of the text for easy reference, illustrating the science and the systems with diagrams and figures, for drawing on case studies that offer "...tips, hacks and things to bear in mind when developing our own systems," and for providing useful tools for working with magnets.

The Triboelectric Series

Two- and Three-Part Magnetic Systems

As Rumsey concludes, "By producing this book, Gwen Spicer has introduced the wider community to these methods in accessible format, and we can now develop and grow in what we can achieve with it."

This isn't an instruction manual for a quick glance; it's worth spending time with this book to really be able to make creative decisions. While doing so might take longer than reading a set of instructions, we all know the benefits of working in this way for a varied collection. Some might say there's too much science, but this book provides all the information, and it's up to the readers to decide what they need to take away from it to achieve their own goals.

Order Magnetic Mounting Systems for Museums and Cultural Institutions

Magnetic Mounting Systems for Museums and Cultural Institutions for Sale at a Conference
(Photo Credit: K.Sclafani, GHHN)

Ms. Rumsey's review appeared in the December 2019 issue (75) of News in Conservation, the newsletter of the International Institute for Conservation of Historic and Artistic Works.

Magnetic Mounting Systems for Museums and Cultural Institutions is now available!

The book is now available and it is time to get yours today! 

We have been waiting for this day for a long time. I especially want to thank all of those who pre-ordered books. In all, they ordered over eighty books. Some ordered at the time of the International Mountmaking Forum in London. Since that meeting, there has been a steady flow of orders from museum professionals, framers and mountmakers globally. I have been overwhelmed and pleased by this early support and enthusiasm for the book.

All the boxes delivered. 

The book! It looks really great, too.

How do I get a book? It is easy, you can go here to place your order and we will ship a copy to you.  Are you going to be at this years AIC annual meeting in Connecticut and don't want to wait or pay for shipping? It is only a few weeks away. I will be there too selling copies of the book.

How do you find me at AIC? You can find cards with ordering information at SmallCorp's table in the exhibit hall. Or look for conservators wearing a large button with the book cover. These conservators will also have cards with ordering information available. Or you can just find me walking around. I will have books available for purchase and am happy to arrange meeting up with people to facilitate the purchases; just send me an email at gwen@spicerart.com and we can work out the details!

An assembly line was needed for
the packaging of all of the books.

These books are headed abroad!

All of the pre-ordered books packaged and ready
to be shipped out!

Pre-Order Magnetic Mounting Systems for Museums and Cultural Institutions and Save!

We are excited to announce that Gwen's new book, Magnetic Mounting Systems for Museums and Cultural Institutions, will be available in December and we are now taking pre-orders through April 15th at a 10% discount off the cover price. Order your copy today!

The book is an essential text for mount-makers, exhibit designers, museums professionals, curators, conservators, collections managers, archivists, and architects. It systematically explains magnetic behaviors and the procedures involved in developing magnetic mounting systems for artifacts. With actual case studies and over 80 photographic images and drawings, the book explores a broad range of applications, including artifact types and magnetic systems that can be employed and manipulated for uses in exhibition and storage.

Magnetic Mounting Systems for Museums and Cultural Institutions is an essential reference text for any reader planning or executing displays, including mount makers and exhibit installation teams within museums and the commercial exhibition industry. It is a must have for everyone who displays collections in museums of all sizes, galleries, archives, libraries and private collections. It will be beneficial to conservation students and any technical staff who wish to employ magnets in their proper fashion to insure the safety of objects they are installing or mounting.

Table of Contents



Additional information

• Softcover
• Over 400 pages
• 59 case studies each with cross-sections and images
• 16 chapters with extended glossary, appendixes and reference list
• 44 tables
• Chapters contain "how to's," "Useful tips" and "Wacky behavior"
• Available May 2019

Learn more about magnets and their many uses in the new publications Magnetic Mounting Systems for Museums and Cultural Institutions. Available for purchase at www.spicerart.com/magnetbook.

What are Flexible Magnets?

You know them and we bet you even own a few! We're talking about flexible magnets, also sometimes called refrigerator magnets, which first appeared as a type of ceramic magnet in the 1960's. 

Because they're made with flexible resins and binders (synthetic or natural rubber) this type of magnet can be produced as 1) extruded magnetic profiles that are usually coiled or 2) in sheets, resulting in a wide variety of options and properties. For example, extruded flexible magnets are often found on shower door or refrigerator closures. Magnetic sheets, on the other hand, can be cut into all sorts of shapes and sizes, and are what you find holding that souvenir of your summer vacation to your refrigerator door or office filing cabinet.

When flexible magnets are extruded, they pass through a line of powerful cylindrical permanent magnets or a rotating magnetic field. This step allows for the creation of a wide variety of options. For instance, they can be formed to have holding power on both sides, or only on one side. 

The most commonly arranged magnetic poles occur in an alternating line format on the same surface plane (NSNSN or SNSNS). An interesting phenomenon occurs when two layers are slipped slightly on top of one another: they both repel and attract as one slides across the surface of the other. One side of the flat surface is more magnetic (has an increase in holding force) than the other. This arrangement of polar direction is called the Halbach Array. It is this alternating polarity that creates modest attraction (fig. 1). 

Figure 1: A cross-section of a Halbach array with the alternating poles that create a stronger magnetic
field on one side and a weaker one on the other.

The most common style used in museums is the multi-pole on one side. In museums, flexible magnets are commonly used to attach accession or object numbers in documentation photography, for overall humidification as a substitute for weights, holding wrapper enclosures closed, and mounting of lightweight flat artifacts. Their continuous magnetic field is ideal for overall support; their low pull force, however, does not allow them to support heavy or thick items (Schlefer, 1986; Stenstrom, 1994; Braun, 2001; Keynan et al., 2007; Vilankulu, 2008; Heer et al., 2012; Migdail, 2013).

The pull force of flexible magnets is quite weak, and they have low magnetic strength when compared to a non-bonded magnet. Today, the flexible-style magnet is also formed with neodymium (further described in the following section), creating a much greater pull force. Thickness of the flexible material is in direct relation to the pull force of the magnet. Manufacturers specify pull force in pounds per square foot. Pull force is related to thickness; the thicker the sheet, the stronger the magnet. A flexible magnet .04 cm (.015 inches) thick has a pull force of roughly 40 pounds per square foot (0.278 PSI) while a flexible magnet .08 cm (.030 inches) thick has a pull force of roughly 85 pounds per square foot (0.59 PSI). No other magnet type has such clear-cut specifications; therefore comparing flexible magnets with others is not easily transferable (table below).

Table: Thickness of the flexible magnet and the pounds per square inch of pull force

Thickness	Approximate pounds per sq. ft.	Pounds per square inch (PSI)
.012	30	0.2
.015	40	0.278
.020	60	0.417
.030	85	0.59
.060	144	1

Flexible magnets are very susceptible to demagnetization, especially when in contact with other stronger magnets and with other similar flexible magnets (fig. 2) (Livingston, 1996). They also appear to lose their magnetization over time, likely due to proximity to other magnets. Flexible magnets are less susceptible to demagnetization by their Curie Temperature. When used in a situation where strength is needed, they should be checked occasionally.

Figure 2: The parallel rows of the flexible magnet visible with a
'magnetic viewing film (left). The same parallel rows disrupted
when exposed to a rare-earth magnet (right).

Flexible, bonded type magnets are conducive to creating large area pressure type systems. These ferrite-bonded magnets are weak, but to increase the strength, the polar directions are arranged as in a Halbach Array during manufacture. It is this alternating polar direction that provides gentle pressure, evenly dispersed over an entire surface. Conservators use the standard magnetic orientation of a magnetic force on one side. Sheets can vary in alignment when placed together and should be trimmed as a pair. Their strength can be increased somewhat by using both thicker flexible magnets and a related gauge of metal (Spicer, 2014). A second layer of flexible magnet placed on top does not add to the pull force of the first layer, due to its particular alternating polarity.

The addition of pressure created by the pull force can both introduce and assist in the removal of moisture during humidification of an artifact. An artifact sandwiched between absorbent materials is given overall pressure either between two flexible magnets or a top flexible magnet layer above and a steel plate below. The presence of the sandwiching method has been noted to slow drying time (Blaser and Peckham, 2006), but the benefit of not having to lift heavy weights offsets this.

Learn more about magnets and their many uses in the new publications Magnetic Mounting Systems for Museums and Cultural Institutions. Available for purchase at www.spicerart.com/magnetbook.

Resources

As a conservation tool, flexible magnets have been successfully used for a wide range of applications, including during humidification of paper and book repair as a substitute for weights (Brooks, 1984; Stenstrom, 1994; and Blaser and Peckham, 2006); an embellishment attachment with two layers of flexible sheets (Braun 2001); and mounting (Keynan et. al., 2007; Heer et al., 2012; and Migdail, 2012).

Hands-on magnet experiments that look closely at particle size

One of my local museums, MiSci, in Schenectady, New York, is a popular hands-on science oriented museum. During my last visit, I was greatly surprised to find a small exhibit with strong magnets that tested the attraction of various iron particle sizes. The exhibit consisted of three vessels filled with liquid (see photo below); at the bottom of each vessel were particles of iron. Each of the three vessels held a different size of iron particles, starting with a "nano" size. Positioned near the vessel were two magnets on vertical sliding rods.

Three vessels with magnets on rods. Each vessel contained different sized
 particles of iron, yet the magnet near each vessel was the same size and strength. 

The purpose of the exhibit was to learn how the particles behave in the presence of the magnet. For the interest of conservation and understanding more about iron particles, this was a wonderful activity to see!

Below is the image of the iron particles that are considered "nano" size or 100 nanometers or 0.1 microns. In the presence of the magnet, the particles are all clustered together very near the magnetic field. As the magnet moves up the vessel the particles stay together following the magnet and traveling easily together in a tight group.

The image below shows a larger size particle, called "magnetite sand" at 1,500,000 nanometers. These particles followed the magnet as it moved up and down on the rod, but did not remain as a tight group. These particles are so small they have fewer magnetic regions that can align to be attracted to the magnet. More about domains can be read in a previous blog post "Magnets are only as strong as ....".

Next is "magnetite powder", at 3,000 nanometers. These particles only slightly are attracted to the magnets. These particles are hardly attached to the magnetic field force. They really just want to sit at the bottom of the container.

So, what is going on here? What might be the difference between "sand" and "powder"? Clearly it is the activity of the small regions, even smaller than the particles called "domains". It is how these domains align in the presence of a magnet that make them attach to a magnet or not.

Learn more about magnets and their many uses in the new publications Magnetic Mounting Systems for Museums and Cultural Institutions. Available for purchase at www.spicerart.com/magnetbook.

What is Magnetized Stainless Steel?

If you don't know it by now, we at Spicer Art Conservation think about magnets a lot. And with Gwen's book, Magnetic Mounting for Art Conservation and Museums (to be published by Archetype later this year), we like to share what we're discovering about their properties and applications.

The other day a client called about how to mount an artifact in their institution using magnets. We worked out a system where counter-sunk disc magnets would be secured to the wall allowing the artifact to be held in place with thin stainless steel discs. The registrar proceeded to order the supplies. She called back a few minutes later asking, "what is magnetized stainless steel?" and then stated, "but stainless steel is not magnetic!"

As it turns out stainless steel is not just one metal, but instead is composed of a group of metals or alloys. All of the metals in this group are magnetic, except one. The confusion lays in the fact that the non-magnetic type of stainless steel called "austenitic" is the most commonly used stainless steel for producing domestic products, and thus it is the type of stainless steel that we are most familiar with. (An example is stainless steel utensils/flatware that have 18-20% of chromium and 8-10% nickel, which is not magnetic.) 

When nickel is added, as with the utensils/flatware example above, stainless steel becomes non-magnetic and its anti-rust properties are enhanced. The more nickel the greater the corrosion resistance. But, its presence also causes the stainless steel to be non-magnetic. This stainless steel is the austenitic type.

The stainless steel alloy has at least 10.5% chromium. It is the added chromium that creates the protective layer of chromium oxides on the surface that prevents the development of iron oxide rust. It is the added chromium that makes the metal both rust and scratch resistant, and with the increase of chromium, resistance is also increased. Chromium can make up as much as a quarter of the weight.

Magnetic stainless steel is based on the amounts of alloying elements as described above as well as on the grain structure and the amount of cold working. Another interesting fact is that austenitic type stainless steel with a low amount of nickel can be reverted to a magnetic type when cold hardened. However, it is true that the metal has a crystalline structure that has a lower magnetic permeability than just steel alone.

The odd thing you might now being asking is, "But nickel is ferromagnetic! How can it NOT be magnetic?" Therefore, you would think that when nickel is added to iron and chromium it would be even more magnetic. But this is not the case! Why this happens is based on the different atomic arrangements between face-centered cubic (FCC) and body-centered cubic (BCC) -- austenitic with nickel and ferritic without nickel, respectively.

 

Face-centered cubic (FCC)                        Body-centered cubic (BCC)

Therefore, if you want a ferromagnetic material that will not easily corrode and has a thin profile, stainless steel is a great option for that magnetic system.

Learn more about magnets and their many uses in the new publications Magnetic Mounting Systems for Museums and Cultural Institutions. Available for purchase at www.spicerart.com/magnetbook.

How do I camouflage my magnets?

There is an increasing interest in the use of magnets, both in museums and among the general public. In many museum exhibits it is desirable to make the magnet blend with the artifact being mounted. Conservators and mount makers have used many methods of disguise to achieve this. A magnet or ferromagnetic material can be used and disguised quite easily (For more on what a magnetic system is, read our other posts: http://insidetheconservatorsstudio.blogspot.com/2013/05/ferrous-attraction-and-science-behind.html and http://insidetheconservatorsstudio.blogspot.com/2015/05/a-magnet-is-only-as-strong-as.html). 

The camouflaging method selected is often based on available supplies, expertise, and the experience of the practitioner. Other aspects depend on selecting a substrate similar to the artifact's texture, color, pattern and design. Concern for the durability and the magnet placement depends on the situation. In particular, the magnet's tolerance for being handled multiple times. Also, concern for its proximity to the visitor, especially in the case of patrons who might be susceptible to a magnet's effect (pacemaker wearers, for example).

Useful Tools:

If you must trim any material after it has been attached to the magnet, the use of metal tools like standard metal scissors can be frustrating because your tool and magnet are attracted to each other. Luckily tools made of zirconia (Zr, atomic number 40), like knives, are perfect and will not be attracted to a magnet. These knifes are very sharp and brittle, so great care is needed to prevent them from breaking.

Useful non-metallic tools that won't be attracted to a magnet

Below is a list of various options for camouflaging a magnet:

A) PAINT

A layer of paint can be a quick camouflaging method, but it also brings challenges. One, is creation of an uneven application (it can be difficult to apply an even coat on the plated surface of a magnet). Another, is protecting the applied surface. An added protective coating is useful to aid in reducing the potential of chipping. Another option is to "rough" the surface slightly, allowing for a better grip of the paint to the magnet surface.

The painted surface on a magnet will become chipped or marred when opposing sides are quickly snapped together. This often occurs when magnets are removed and stored, or are placed near one another during preparation when ferromagnetic materials are not present. To minimize this problem, ensure that all of the magnets for one project are stored with the poles in the same direction, so that the fragile painted layers repel each other.

This might not be a choice for magnets that are used regularly. However, it can be an easy and quick method for short term needs. To do this, place them on inexpensive plumber’s tape behind silicone Mylar, scrap steel, or a metal filling-system. (see the image below).

Using a layer of adhered paper or Japanese tissue below the paint layer can improve the cohesion. For more about painting magnets go to: http://denverartmuseum.org/article/how-dam-prepared-rare-earth-magnets-installation-oceanic-textiles

These block magnets are spaced far
enough apart to discourage them from
snapping together quickly.  

B. DIGITAL PRINT

An excellent camouflage technique is to use a digital image to duplicate the surface that the magnet covers. Larger flexible magnets are ideal for securing thin artifacts. Several conservators have published the technique, but on-line you can go to the Asian Art Museum's blog (http://www.asianart.org/exhibitions_index/batik-mounts) to read about it. 

A digital print can also be added to the outer surface of any rare-earth magnet (see photo below). 

Camouflaging is created using a long flexible magnet that
is covered with a 1:1 image of the artifact it will secure.

C. COVERING LAYER

Another approach to disguise the magnet is to apply materials that are the same, or with similar texture, as the artifact that is being supported . The materials are disguised by the color, texture or images in the local area that is being covered, or even the actual embellishment itself (see the decorative element section below). Examples of materials that have been used include Japanese paper, mat board (http://www.conservation-wiki.com/w/index.php?title=Magnet_Mounts), Nomex, fabric (http://spicerart.com/2014/12/17/hunzinger-chair-re-tufted-with-magnets), Tyvek, felt, leather, artificial rawhide, and ultra suede.

When fabric is used, using a sufficiently tight weave-structure to withstand the strength of the magnet is recommended. If the weave-structure is too loose, then the fabric weakens prematurely.  

Creating tufting on a chair seat using magnets. These magnets 

will be covered with the same red show-cover fabric, creating a 

camouflaging of the magnets.

D. DECORATIVE ELEMENT

Conservators have cited the magnet itself as the decorative element and hence requires placement above the artifact. The decorative element in this case aids in determining the size and strength of the magnet. If the magnet is replacing a missing element, then the size is predetermined. But the grade can be adjusted to better match the magnetic system.

When a magnet is securing the element to the artifact the magnet needs to have the strength for support. The element can be a range of sizes and shapes, large; and flat or small footprint and tall. A magnet must be selected that will secure the element, while also not damaging the artifact below. 

Read more about disguising magnets as decorative elements at the Asian Art Museums website: http://www.asianart.org/collections/magnet-mounts 

Decorative element secured to a costume using a magnet.

E. Embedding

A successful method of placing rare earth magnets within materials is embedding them properly. Keeping the magnets surrounded by materials aids in their longevity, by lessening the risk of demagnetization from both shock and heat. These embedded magnets or ferromagnetic materials can be placed on top or within an artifact, as well as used as a point fastener, or as continuous pressure on the artifact. 

Any three-dimensional artifact can be easily mounted and supported. The magnet or ferromagnetic material can be embedded and hidden inside. In addition, many of these systems can be reused. The wide selection of materials used are Ethafoam, pillows with batting and a baseboard, materials that are easily carved, and rigid or simple acid-free board.  Read more about creating mounts here:

(http://insidetheconservatorsstudio.blogspot.com/2013/01/creating-mounts-with-magnets-for.html)

Ferromagnetic material attached 

to an acid-free board inserted 

into the base of a wooden box.

The shape of the magnet, whether using a disc or a block, does not affect many of the methods described above. The only exception is cutting a hole into mat board. Here having a block-shaped magnet could be simpler than cutting a round hole, but a drill bit can be used.

At Spicer Art Conservation we are always interested to hear of magnet use success stories. In fact, Gwen Spicer, owner and principal conservator of SAC is busy writing a book about the use of magnets in conservation. The book features examples of successful magnet use by conservators. If you have a story or project you are particularly proud of, and would like to possibly be included with other successful magnet using conservators in the book, please share your own experience of covering and camouflaging magnets. We want to hear!

___________________________
Gwen Spicer is a conservator in private practice. Spicer Art Conservation specializes in the conservation of textiles, objects, and works of art on paper. Ms. Spicer is known for her innovative treatments and mounts using magnets. 

Learn more about magnets and their many uses in the new publications Magnetic Mounting Systems for Museums and Cultural Institutions. Available for purchase at www.spicerart.com/magnetbook.

To contact Gwen, visit her website: www.spicerart.com or send her an email: gwen@spicerart.com.

So, how do I store my magnets?

I recently returned from the 5th Mount Maker's Forum, held at the Cleveland Museum of Art, Cleveland, Ohio.  It was a great meeting, full of enthusiastic mount makers, all sharing great ideas and solutions with one another.

I was fortunate to be able to both give a talk, "Stick to it, magnetic mount-ineers!" and present a poster, "Magnets as an Alternative to Velcro". The mount makers had many questions regarding the use of magnets.  "What is the best way to store them?", was one of the most frequent questions I was asked.  I  realized this topic made for a perfect blog post, therefore, here it is!

As mentioned in earlier blog posts about magnets, there are four permanent magnets. Each type of magnet has its own needs for long-term use and continual performance. Which is no different from museum collections, or any other equipment that you might use. Some magnets are effected by shock or mechanical action, others are brittle and break easily, and others are effected by temperature or moisture. All of these are issues of handling and environment, which conservators and other museum professional are especially suited to understand. Depending on the class of magnet, the care will vary slightly, but, with proper care, little decay should be noticed.

Various magnets held in film style containers and separated by foam disks.

Coercivity (Hc) is the process where a magnetic field is reduced or eliminated. Each permanent magnet has its own coercivity rating. The higher the Hc, the greater the resistance to demagnetization. Understanding the Hc of permanent magnets, and other materials and equipment that surrounds us, is necessary when working with strong magnets. Rare-earth magnets currently have the highest coercivity values.

What causes coercivity?

MECHANICAL SHOCK

Several magnet types are brittle* and can easily fracture. This is especially the case with rare-earth magnets, when impact and tensile forces affect them. In fact, many suppliers do not guarantee against poor handling due to this fact.  Since a sharp hammering, or any physical shock, can cause demagnetization, it is necessary to prevent magnets from quickly jumping to one another or dropping to the floor from a raised height. Once a magnet is broken or cracked, it is highly susceptible to moisture and corrosion. Do not attempt to use them by positioning them together or gluing them together. Chipped or cracked magnets with peeling or spalling surfaces should not be used since the protective coating has been disrupted (Campbell, 1994).
*NOTE:  Brittleness increases as the grade number of the magnet increases.

Cracked magnets should not be used.

HEAT and Curie Temperature (Tc)

Each permanent magnet has a Curie temperature (Tc) that identifies the point where the material’s magnetism is eliminated. Neodymium magnets are very sensitive to high temperature* and therefore have the lowest Tc of the permanent magnets; Alnico and samarium have the highest Tc values. This is one of the reasons why Alnico magnets are still used. Be sure to stay well below the Tc of each permanent magnet used.
*NOTE: This is why hot glue can be dangerous when used to adhere rare earth magnets to a surface.

MOISTURE

As stated earlier, Neodymium is easily oxidized. In a magnet, an oxidized surface lowers the pull force of the affected layer, therefore allowing that region to demagnetize more readily (Campbell 1994, Drak & Dobrzanski 2007). A coating of nickel-plating, or epoxy, is applied to prevent this from occurring. Blistering and spalling of the surface can be seen, more readily with two-layer copper nickel plating (Drak & Dobrzanski 2007). Even during the manufacturing process, oxidation prevention measures are required, often using a vacuum or argon gas environment. A sintered magnet is less stable than a bonded magnet against oxidation induced demagnetization corrosion (Campbell 1994; Trout n.d.). If a neodymium magnet is used in a raised relative humidity location, a bonded magnet is recommended (Drak & Dobrzanski 2007).

A N52 magnet that was used in a salt water environment;  the magnet is corroded and is no longer usable.

DEMAGNETIZING FIELD

Some types of permanent magnets influence or weaken other magnets. One such case is when a ceramic (including flexible type) or samarium magnet is demagnetized by a neodymium magnet. As a result, neodymium rare-earth magnets should always be stored away from other magnet types. Similarly, electronics systems that rely on magnets to hold information, such as hard drives and disks, can be altered or demagnetized by a neodymium magnet that is placed nearby. Magnetic strips on credit cards and other cards can also be affected, as can electronic devices.

The statement above appears on stickers that we adhere to the magnet cases at SAC.

Ferrite magnets can be demagnetized when their poles are alternated, a reason to carefully stack the magnets. This is especially the case with the bonded flexible type; sliding a magnet side-ways perpendicular to the polar rows demagnetizes the array. Alnico type magnets are unique in that they can be remagnetized by realigning the internal domains via another strong magnetic field. This is not the case with other magnets, especially neodymium ones, where once demagnetized, the magnetism cannot be recovered.

Each type of permanent magnet should be segregated and spaced well outside other magnetic fields. As more magnets are concentrated together, the field increases. A safe approach is to separate each type in the work area.

To summarize this information, here is a table of the different categories with the various permanent magnets:

	Alnico	Ferrite	SmCo	Neodymium
Use keeper for Horseshoe shape	X
Wrap to prevent abrasion		X
Group by size		X	X	X
Stack, orienting N to S		X	X	X
Place separator between			X	X
Moisture and RH sensitive				X
Demagnetizing Field (Hci)	Can be easily demagnetized. When repetitively placed north-pole-to-north-pole ends together, it quickly weakens itself.	Keep them away from Rare earth magnets.	Can be demagnetized by NdFeB magnets. But they do not weaken others.	Tough to demagnetize. This also means that they can easily demagnetize other classes of magnets like SmCo or Alnico or Ferrite. Shock can demagnetize.

Finally, with all of this information, let me show a few images of how I store my magnets.

Magnets are stored with a separator (black foam) between and in compartments lined with foam.  These small magnets are placed in "day of the week" pill containers.

-Individual small containers clearly labeled with type, grade and size.

-storing in divided boxes of a wide range of types.

-contact lens containers are wonderful to keep strong individual magnets separated from others.

-interleave magnets stored together with cardboard, foam or matte board for ease of separation

-Neodymium magnets are separated from other types of permanent magnets as that they effect their coercivity when in near proximity.

NEVER store you magnets next to a heated surface, like an oven or radiator; the location is too hot. Why? because some rare earth magnets have a low Curie temperature and thus, will demagnetize (and become completely useless) with heat.



















_____________________________
Gwen Spicer is a textile conservator in private practice.  Spicer Art Conservation specializes in textile conservation, object conservation, and the conservation of works on paper.  Gwen's innovative treatment and mounting of flags and textiles is unrivaled.   To contact her, please visit her website.

Learn more about magnets and their many uses in the new publications Magnetic Mounting Systems for Museums and Cultural Institutions. Available for purchase at www.spicerart.com/magnetbook.