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!

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.

Mounting Quilts with Magnets for Display or Exhibit

by Gwen Spicer, Principal Conservator, Spicer Art Conservation, LLC

SAC has been answering many inquires from several museums and private organizations regarding the mounting of quilts, other textiles and skin artifacts with magnets (More information on magnets can be found at SAC's website).  The increased inquiries show first-hand how the field of conservation is interested in using magnets, while also continuing to find an alternative to the use of Velcro for mounting and hanging.

As with any new material or technique, concern of how magnets work and any known adverse outcomes are the most prominent subject of questions asked.  Also the challenge with using magnets with textiles, and especially quilts is that some textiles can be quite heavy.  This creates a concern with downward pull of the artifact and of sheer stress of the system that could result in failure, or compression of the artifact at the magnet site.

Quilts in particular present interesting problems when using magnets.  Quilts are complex; made in a range of sizes, materials, and thicknesses.  Due to this broad range of quilt characteristics, the sheer stress factor, and the need to prevent slippage or compression of materials, the potential for failure seems high.  However, with the proper planning and understanding of how a magnetic system works, its strengths, and any limitations of the type of magnet you select, the potential for failure is then quite low.

We have talked in the past about what is a "magnetic system".  The system as a whole is a significant factor in how the magnet behaves or is able to perform the task (Feymann 1964; Livingston 1996).  The magnet works in conjunction with two other parts, these three factors together create the system:

1) The actual strength of the magnet itself; care is taken to ensure the magnet is not too strong, and not too weak.

2) The ability of the metal behind the textile to be magnetized.  The receiving metal must have enough receptivity to allow the magnet to "stick" to it with its fullest ability. 

3) The space between, or the gap created by the layers between the magnet and the metal behind (or receiving metal).  These gap layers consist of the artifact and any buffering layers - mount fabric or mylar for example.

When magnets are placed on the surface of the quilt, the gap or field distance becomes an issue. Often the strength of the magnet is increased to ensure a strong magnetic field, but then puckering or "tufting" of the quilt's surface becomes visible.  Below is an image of magnets used as a point-fastener system; the magnets, while painted to match the quilt squares have created a puckered look. 

What could a textile conservator or curator do to eliminate this?

Magnets used to mount this Civil War era quilt are
obvious, even though they have been carefully
painted to match the surface of the quilt. The quilt is
safely mounted, but the puckering or tufting of the
quilt becomes problematic.

Our favorite solution is the Magnetic Slat sold by SmallCorp Inc.  A solution that solves the issue of a heavy weight textile by using an aluminum strip with a small lower lip (L-Shaped in cross-section) to support the textile, while rare earth magnets hold the textile back against the aluminum strip.

Grade N42 magnets, measuring ¾” dia. X 1/8”, with counter sunk holes are fastened along at 6” intervals on the vertical side.  A 22-gauge steel piece is held into a stitched sleeve along the upper edge of the artifact (Wood 2013; Spicer 2013a, c).  In this solution the lower lip actually holds the weight of the artifact, but it is the strength of the magnets that ensure that the steel piece is held back and onto the aluminum horizontal element.  The solution appears to be unlimited.  A textile weighing 60 lbs. was successfully hung with this magnetic system.

Above: The aluminum slat with "L" lip and countersunk magnet (silver).
The ferromagnetic steel piece (white) sits perfectly on the lip and is
held in place by the magnets. NOTE: The steel piece is shown without
the webbing sleeve. See below for the steel slat in webbing sleeve photo.

Above:  Here the slat as it slides into a webbing sleeve (one piece 2" webbing,
the other 3" webbing). Below, see it as it is affixed to a 30 foot long
weaving. The system was used to hang several weavings, the heaviest
of which was over 60 lbs.

Above: The slat is inside its webbing sleeve and has been attached
to the textile.  Special consideration is always made to test the
hanging of the textile to be sure the slat is affixed to allow the
textile to hang properly.

Problem solved. The magnets can be as strong as you want them to be, and you never have to worry about puckering or compression.  It is simply because the quilt is no longer between the magnet and the receiving metal, instead all the magnetic pull is happening behind the artifact.  We have moved from a system where the magnets are being used as a point-fastener on the face of the artifact, to a system that distributes large area pressure behind the artifact.  It is like moving from hanging a painting on a wall by hammering the nail through the painting, to hanging it with wire mounted to the frame.
_____________________________

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.

Magnets & Health in Conservation

We use rare earth magnets quite often here at Spicer Art Conservation. One of the many questions that we hear from fellow conservators, curators, and others who are using magnets in treatments or exhibit mounting is: 

"Are magnets dangerous to my health and are there negative effects from my close proximity to strong magnets"?  

Rare earth magnets surround our everyday lives, but we may not realize that they are hidden in our cell phones, other devices, ear buds, etc. Medical professionals have investigated the dangers of a patients proximity to rare earth magnets mainly because of their concern with the effect of magnets on pace makers, defibrillators, and brain shunts. Why the concern? Because the settings on each of these medical devices is controlled by magnets.

All magnets, when purchased, come with warnings about their effect on pace makers in particular. A pace maker, or defibrillator, deliver signals to the heart, causing it to beat without regard to the patients’ underlying heart rhythm. When exposed to a magnet the device works improperly or is deactivated. Pace makers or defibrillators are negatively affected starting at 10 gauss (however, conservative estimates place this number at 5 gauss). This can result in a pacemaker missing a beat or cause an ICD defibrillator to temporarily stop looking for abnormal heart rhythms. As a comparison: headphones have small magnets with field strengths as high as 200 gauss or more (that's 20 times more than the dangerous limit of 10 gauss or 40 times the limit of the more conservative 5 gauss limit).

Internal parts to Earbuds.

But how close does the magnet need to be to be dangerous? Researchers agree that the magnet (or in this case device, headphones, etc) should not be placed directly on a patient's chest. However,  researchers have found that if the headphones were placed at least 3cm or 1.2” away from the chest, they were shown to have no effect (Morphy 2008). 

Therefore, in the museum world, the real danger of magnets might be to the conservator or preparer, and not as much to the visitor to an exhibition. A visitor most likely will not be close enough to any artifact or object within a case to be effected. As a courtesy, a small sign could be placed on stand-alone cases. Only an artifact in a small-bonneted case where something might need close inspection might be an issue if a particularly strong magnet was used. 

The chart below comes from K & J Magnetics where they have provided magnet sizing guidelines to reach a 5 gauss or lower reading. This chart and their article on "Pacemaker Safety" can be found on their website.  

Luckily, pace maker technology is changing, with new devices unaffected by the magnets in electronics. We live in a world that is being saturated with waves from wireless services, devices and their carriers. It is unclear what all of this does to us. But for now, art conservators, curators and museum exhibit preparers do not need to be worried that our attempt to best support our heritage will badly effect our visitors.

And what about us? As practitioners (especially those who use an implanted device like a pace maker), we do need to remain at "arms length" from magnets, and no problems should arise. However, our exposure to magnets when mounting or treating an artifact is limited to a brief time period. The real issue for all of us seems to be our own personal electronics and how much exposure we have to these items that have "invaded" our lives. 

The bottom line, don't be afraid to use rare earth magnets to mount or treat an artifact. And if you have an implanted medical device, don't put the magnets near your device.

For additional information read these:

• Morphy, Erika 2008 "Study: Headphone Magnets Mess with Pacemakers", TechNewsWorld
• As always, K & J has exceptional information about magnets (for example the chart above comes from K & J's page on pacemaker safety). But there is so much more! Look around their website for all the other magnet information they offer.  

_____________________________

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.