Flag conservation

Flag conservation
Textile conservator, Gwen Spicer at work

Thursday, November 5, 2015

Objectivity is essential when evaluating artifacts

A conservator is often trusted to determine what something is, where it comes from, and the time period in which it was made. And while we are not antiques dealers, nor can we give an estimated sales price (a la "Antiques Road Show"), it is often a conservator who is sought to weigh in on the authenticity of an item, simply from the perspective of an expert who is in close working contact with artifacts on a daily basis.

Recently, I watched a fellow textile expert look at a textile composed of silk and wool. The owner had hoped the artifact was from a particular time period, and it was quite likely to be, but the provenance of the piece was largely unknown. It was not until after the examination of this textile that the expert asked for the "story". So as not to be biased by the hopes of the owner, this expert based their examination on the hard evidence: thread count, weave structure, dyes used, degradation of the silk areas, stitching methods, style of the piece, hems, selvedge ends, (and other things that textile folks find fascinating!).

In a blog post written not long ago, we spoke of dating objects and our research into the "sprang" weave structure of a sash from the War of 1812. That blog post has received 1000's of views, and lots of comments and emails asking us about the dates of similar objects. In the studio at the same time was a beaver felt-style chapeau with "1812" prominently sewn to the front flap with a lovely decorative cord. And while it would be easy to say it was from 1812, that was not the case. From observation alone, the hat was quite worn and featured the date to commemorate the War of 1812, that was certain. But was it worn in battle? That seemed unlikely from several factors: the materials used to construct the hat, the condition of the hat, the rank of the owner, and the style of the hat was from a slightly later period (so while it was similar, it had distinctly later features). Our findings were discussed in our blog "what's in a date?".

Was this hat worn in the War of 1812, or does it commemorate the War of 1812?

There are many items that commemorate dates, like the 1812 hat above, that can easily be thought to originate at the time or event they commemorate. Such is the case with flags, pennants, buttons, banners and other items that are reproduced for a celebration, especially a centennial or significant anniversary.

On the other hand are objects that have a strong story or a label that was affixed to the object a long time ago. These are items that have history from legend retold or sometimes from documentation that is quite old, but does not go back to the date of the object.

For example, a lovely textile, which came into the studio along with some other artifacts, was believed by the owner to be something quite extraordinary. For this owner, family tradition had cemented the importance of the garment they believed to be from the late 13th century. Yet, the story (which was beautiful and had accompanying documentation that dated to the mid 1800's) was not plausible for a variety of reasons. The most persuasive factor was that this artifact was made using a technique that was not known until hundreds of years later. Also this textile was in very good condition, yet was hoped to be a 740 year old garment.

A lovely knitted garment with open work and ribbed scalloped edges. Family
history claimed it was knit by a queen in the late thirteenth century.

It was a surprise to the owner that another item in their collection was actually older, and was the one that was remarkable. This textile (photo detail below) was used as a protective covering to hold a circa 1800 book. The covering is a pouch made of linen with silk, and the embroidery is wonderful. When we commented on it, the owner stated that the textile was always "just the bag used to protect the book". The bag was clearly not made for the book, the book just happened to fit inside and so the two are now, and for many past decades, "together".

Detail of the small embroidered pouch. The owner was surprised that it
was possibly a 17th century piece depicting King David playing his harp.

Sometimes an item will be misidentified as something it is similar to, but is not: "Japanese Kimono", "Tapestry", "battle flag", etc. will turn out to be a Chinese robe or a weaving that was hung on the wall, or a flag made to commemorate a military unit. These long standing labels can be difficult to shed. And often it is difficult to tell the client that what they have is not exactly what they think they have. However, the history of the object is still there, it's just different than what was assumed, but certainly just as (and sometimes more) interesting.

Is this a Revolutionary War era flag because it features 13 stars? One must be cautious that the number of stars, does not automatically mean the flag is from that specific time period. Flags, like the 1812 chapeau above, are often made to commemorate the anniversary of an event. 
Depending on the artifact, whether it be a textile, object, paper etc. Particular attributes are important. Objects made of wood, metal, glass or any medium all have specific characteristics that are indicative of the way they were made, and often when they were made. As discussed above, textiles can be quite telling when you look at the way they are woven, the fabric they are composed of, or the way they are dyed.

Why is dye analysis so important and what can be learned from it? Dye analysis is not meant to tell the date something was dyed, instead it is used to determine if a dye is natural or synthetic. We know that synthetic dyes were discovered in 1856. This is a clear date line because regardless of the appearance of an item, if the dye present in it is synthetic then the item absolutely cannot be dated before 1856.

More so than analysis, or even hard facts, is the simple fact that you must remain unbiased from trying to make an artifact fit into a particular era. For example, recently an item came to us that had been framed. The item was believed to be of a particular time because of the frame. However, the item was separate from the frame, yet because they had been together for so long they were assumed to be one in the same.

Determining an artifact's authenticity or period of manufacture or era can be quite difficult (if not impossible) without supporting documentation or a lot of unbiased research. Bias is a dangerous thing, hence is why scientists guard against it in their research to remove their predispositions from the outcome. It is no less dangerous in attempting to prove validity in dating artifacts, proving authenticity or establishing provenance.

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.

Friday, October 9, 2015

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 deactivatedPace 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:

  • K & J Magnetics webpage on "Pacemaker Safety". 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.

Wednesday, August 12, 2015

The conservation of 17th century needlework textiles, a conglomeration of stitches, symbolism and media

Mid-17th century English Stump Work embroideries feature a variety of symbolic images, with a variety of stitches, using a variety of materials. These pieces truly are are early "multi-media" pieces, and with their complex embroidery is a multitude of conservation needs. These 17th century pieces are rendered in a raised-work style, often referred to as "Stump Work". The images depicted in the needlework, the techniques and materials used, make these stump work embroideries all similar in appearance.

Recently in the studio was an embroidery called "Mordecai and Esther". It is named after the biblical story, yet the image is of Esther and King Ahaznerus of Persia. According to the story, Esther marries the King, and as his queen bravely implores his mercy to save her people from execution.

17th century English needlework conservation, professional textile preservation, restoration, Upstate Albany New York, Spicer Art Conservation, collection of Newport Restoration Foundation
The overall image shows the density of embroidered symbols. Notice the windows in the town, they shine due to pieces of mica embroidered into the work. Below is a detailed image of the mica windows. From the collection of Newport Restoration.

17th century English stump work embroideries were filled with religious references and symbolism. The restoration and preservation of these multi-media artifacts needs to be approached carefully. This embroidery was expert preserved and repaired by a professional conservator at  Spicer Art Conservation in New York State

Biblical stories are found frequently in embroideries of this time, the story of Esther is quite common because it was accepted as "historical" because it was Old Testament, and therefore not seen as overly religious (so it would not offend). The following quote describes this type of work quite well:

"The variety of method was almost infinite, though the range of subjects was limited.  The curiously disassociated juxtaposition of "curiosities', mythological, religious, natural historical and even heraldic, in unrelated scales, combined in creating an atmosphere of magic or fantasy" - Lanto Synge in Antique Needlework 1982

These needlework textiles are heavily worked with symbolic images. (Much is written on the symbolism found in art, and especially symbolism in textiles such as tapestries). This work alone includes:

  • Stag (in corner)
  • Lion (in corner)
  • Unicorn (in corner)
  • Leopard (in corner)
  • Birds of various species
  • A water fountain
  • Clouds with rain and a rainbow
  • Sun placed at the top, center
  • Fish in a bird's mouth
  • Trees - various: pears, grapefruit, orange? pomello?
  • Insects - many species and sizes, disproportional to things around them, i.e. bug same size as bird
  • Flowers - various
  • Camel
  • Squirrel
  • City or town in the background

Detail of symbolism in 17th century English stump work embroidery, conserved at the textile conservation studio of Spicer Art Conservation, New York
Detail of symbols and "distortion" of proportion (hare and peacock are the same size as a caterpillar, which is on the same scale as a flower).

The multitude of stitching techniques and symbolic imagery is typical of needlework from the mid 1600's. In fact, as we looked at some other examples, the style and manner in which the pictures are stitched makes one biblical story was almost indistinguishable from another. Below is a needlework picture from the collection of The Metropolitan Museum of Art, the similar features are obvious.

another example (this one from the collection of the Metropolitan Museum of Art) of a 17th century English stump work embroidery very similar to the one conserved by textile preservation expert, Spicer Art Conservation, located in upstate New York

These multi-media needlework pictures require the conservation of a multitude of elements including:

-Silk ground, backed in linen, with backing of silk.

-Silk thread, metallic thread, metal sequins, glass beads, pearls, mica

Closer inspection shows unique stitching techniques to create flat satin shiny areas, richly complex stitches creating 3-D images, and elements like pearls and sequins and chips of mica to create areas of interest and detail. Stitching techniques include (but are not limited to): tent stitch, gobelin, satin, french knot,  couching, rococo, detached buttonhole, etc. The satin stitch is easy to examine and clean in that the stitch is flat and easily seen. The knotted stitches and the dimensional work is much thicker and gives "nooks and crannies" for dirt to hide and mask unseen damage hidden below.

Close-up showing the detail of the embellishments to the 17th century English stump work embroidery, recently conserved by textile preservation experts, Spicer Art Conservation
The added beads, pearls and sequins create interest, and more 3-dimensional areas. Below is a closer look, where you can see the metallic threads used to create the robe of this individual.

close-up detail of 17th century stump work embroidery conserved at Spicer Art Conservation, experts in the preservation and restoration of textiles

Regardless of condition, a 350+ year-old embroidery is a fragile textile and must be approached with regard to the age of the materials. This particular embroidery, while dirty and with some areas of loss,  is in good condition. As we always do, the treatment starts with a vacuuming using very low suction and a small brush attachment. When the silk and linen backings were removed, the embroidery showed evidence that it had been trimmed. This could indicate it was the lid or a panel of a larger object like a "casket" (not coffin, much like the one below).

from the V&A Museum, this casket embroidery very much resembles the 17th century stump work embroidery conserved at Spicer Art Conservation
A 17th century stump work casket from the collection of the Victoria and Albert Museum

The needlework we treated had been attached for a very long time to a wooden strainer and had been framed. It was removed from the strainer and placed on a mount constructed of DiBond that was cut to fit inside of the frame. A sealed package was created around the artifact that contained the the new DiBond backboard as well as new Plexiglas and spacers. The original wooden backing was returned, but only after it was separated from the sealed package with an interleaving layer of Marvelseal to protect the needlework from any other possible acid migration.

Some interesting work has been done by conservators using microscopy to look more closely at the complex threads used in these, and other 17th century embroideries, and how these threads were produced. Another interesting find is discussed at length on The National Gallery of Victoria's (Australia) website. While doing their microscopic evaluation they found evidence of peacock feathers used to embellish the bodies and feelers of insects depicted in the embroidery. Sadly, only these small pieces of evidence are left due to the quick degradation of feathers. Their website also includes x-radiography images of a needlepoint revealing hidden pieces of fabric and thread and how they were used.
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.

Thursday, July 23, 2015

Storage for Framed Items Need to Protect the Frames.

One of the many advantages of working on-site at museums is seeing how collections are rehoused and stored. You can also see what clever solutions a museum comes up with that work with their particular situation and needs.

Several years ago, I had the opportunity to consult at the Maine Historical Society in Portland, Maine. They created wonderful protective storage for their framed collections in a closest that was underutilized because it was "out of the way". The closet space seemed perfect to be reconfigured into small segmented storage for framed artifacts. It can be described as a variation on bin storage. Bin storage for framed collections has been around for a long time and is highly recommended. And while it is a good choice, care is needed to ensure that all parts of the framed collection remain protected; This also means the frames themselves.

It is true that at times, the document or portrait is considered the important part of the artifact, consequently the frames are not sufficiently protected. Also, with large bin storage many frames can be housed in a single bin and the items can lean against one another. But most importantly; in a highly-populated bin, when one item is selected, several artifacts are handled. (reducing handling of artifacts is always good practice, read our previous post about lowering the handling of other artifacts, especially those that are wrapped or boxed). In the photo below, large bins are utilized, archival materials are used to interleaf the frames, and corners are protected with padding. A sheet of Ethafoam covers the "floor" of the bins, and it protects the bottoms of the frames.

Traditional bin storage makes great use of space. In the above
photo, notice especially the acid-free corrugated board used as
dividers and the frame corners padded in ethafoam, as well as
the ethafoam on each shelf "floor". The only drawback to large
bin storage is that several items lean against each other.

In the closet at the Maine Historical Society, the segmented spaces are evenly divided in small sections to allow only one to two framed items, perhaps three if the frames were very thin (image below). The sections are labeled for identification.

Padding with Volara sheeting is applied at both the lower and upper horizontal supports. Each framed item is sandwiched between foam-core board, which is very sturdy for interleaving. 

Each area is labeled, so the artifact you are looking for is easier
to find and therefore handling is minimized.
Here you can see the foam core board separators.
Here you can also see the padded lip of the storage opening. 

Another system using Metro International wire chrome movable units is used at the Roosevelt / Vanderbilt, National Park Service's new storage facility in Hyde Park, NY. The system is archival and it is space conscious. This system also allows for custom-sized sections for the bin. The size of the bin should be noted to determine if excessive handling or "paging" through framed items is done before the item being searched for is located. Also, is there any risk of the items being bumped from the side because the rack is accessible from both sides?

In this type of bin storage each item is separated so that
it will not be in contact with another piece.

A view of sliding framed storage. This system ensures that the frames will not be harmed because there is no risk that they will strike another frame or the hanging system itself. Vibration will occur with a system like this, so no framed item that is at risk for loss of media, like a hair wreath or a pastel, should be stored here. 
Another view of the sliding unit. This hanging storage is completely archival. It is costly and takes up
a large amount of space but the framed works are stored perfectly.
This hanging storage slides on set tracks and there is no risk for one unit hitting another.
close up of the sliding tracks from the above unit.

Another take on hanging storage. Care needs to be taken that the
frames cannot hit each other as the storage is moved. Here the units
move like the pages of a book.

A tremendous amount of hanging storage. 

This large hanging storage area is wall mounted and composed of archival components. It uses a great deal of wall space.

These framed items are placed in a hanging storage system that
is compact and thus makes great use of precious storage space.
The use of wood needs to be considered because of its acidity.
Large ornate frames like these are well suited to hanging storage.

Determining the best solution for framed storage is determined by many factors:

  • Space
  • Budget
  • Amount of framed items needing storage
  • Size of the items
  • Ornateness of the frames, 
  • Media used (pastels for instance should not be subjected to vibration from moving racks because the media could be dislodged from the surface of the work, causing it to fall to the bottom of the frame; see image below). 

Each institution will be different because of their unique needs. You may or may not have a wonderful little closet to retrofit, but you do know your collection and you know your storage space. Don't be afraid to think outside of the box and create the best frame storage for your institution.

Need some extra advice? An online guide of types of framed art and how they should be stored can be found through the Minnesota Historical Society. They also have wonderful guidelines for all sorts of things, check them all out. Want an expert collection care consultant to come and help you figure this out? Call an art conservator.
Gwen Spicer is an art 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 artifacts is unrivaled. To contact her, please visit her website.

Friday, June 26, 2015

Collection management in museums where recommendations are being followed

Imagine the success in collection care that could be achieved if the recommendations in a site visit report or collection care report could be followed and implemented?

But for many institutions, by the time a report is deemed necessary, an overwhelmed state has already been reached. The museum staff simply may not know where to begin because the task has been labeled as "daunting". Yet, in some situations the survival of the collection, and certainly the most vulnerable items in the collection, need to be addressed or be lost.

I know, you are reading this and saying, "we are understaffed!", "we have a shoestring budget!" or, "you've never dealt with my board!"

Those are stumbling blocks, no one will deny. But implementing recommendations does not have to be an "all at once" effort, nor does it have to be "everything or nothing at all". Hence is why most recommendations are prioritized and a time-line is projected.

Success Story: The Banner Collection of the Literary and Scientific Circle of the Chautauqua Institution.
The background story is this: the Chautauqua Institution is a small community known for their short intense summer season, and many residents are seasonal only, leaving just a handful of people on-site in the off-season. Many buildings belonging to the institution are unheated in winter.

preservation and conservation of historic textile banners and flags is the specialty of Spicer Art Conservation
Overall of the 1947 banner with its protective covering.

preservation, restoration, conservation of historic and antique textiles. Spicer Art Conservation, conservator
The 1947 banner features a painted surface.

The Chautauqua Institution dates back to 1847. The banner collection dates to 1875 where it is known as the collection from The Normal School, then the Scientific and Literary Circle from 1882. The collection grows by one banner each year as the literary circle creates a banner to symbolize that year. Every banner since the inaugural banner is in the collection. Traditional also calls for the banners to be removed from display/storage and be marched in an annual parade.

About 15 years ago, the Institute called to consult with Spicer Art Conservation about the condition of some of the older banners that had grown quite fragile, as well as to seek advice about the building in which the banners are housed. The building, Alumni Hall, which is original to the grounds, had no basement, no insulation, no covering over the lights or windows, no heat, no dehumidification system, and no air conditioning.

Conservation of historic flags and banners, restoration, repair, preservation, Spicer Art Conservation, collection care survey
Alumni Hall. Some of the banners are reproduced to be hung outside.

The first step was a survey of the collection, included in the survey report were recommendations which were classified into categories. The most urgent needs were identified to be dealt with first, followed by those which were close behind, and finally the needs that could wait. After the survey, a hands-on session was conducted to train anyone in contact with the collection how to properly handle and care for the banners.

collection care of textiles, archival shelving, conservation of historic flags and banners, preservation
One of the shelving units in the collection.

The all-volunteer committee was eager to learn about best practices and while they were concerned about the monumental task ahead of them, they made the decision to move forward, one recommendation at a time, and create the best possible environment for their collection.

The committee worked on each step, they budgeted for things they did not expect (like getting dehumidifiers), and they worked for a solid decade. Ten years later, the collection was reassessed. The collection was being stored, displayed and handled properly. Guidelines were in place, and the environment was being monitored constantly.

preservation of historic textile banners and flags is the specialty of Spicer Art Conservation
Each banner is placed on its solid support in archival shelving with an image of the banner on an identification card.

The Chautauqua Literary and Scientific Circle's (CLSC) collection of banners has become the hallmark for how to implement change and create the best storage and display environment possible for any textile collection. This past week I returned to Chautauqua for another visit to examine the collection and give a talk about the banners and this incredible story of success.

With hard work and perseverance, the entire collection has been conserved properly. If a tiny institution can do it with an all volunteer staff, anyone (who is willing) can do it too.

The banner collection of the CLSC has been featured in our blog once before. That entry is one of our most popular and most viewed. Simply titled "How to Store your Flag Part 1" it has been viewed by thousands and I invite you to view it by clicking the link. There are simple storage solutions there, and it is never to early or too late to implement proper storage.

And of course, if you need a professional conservator, reach out! No project is too big or too small for Spicer Art Conservation. We are here to help institutions, historic societies, private collectors and anyone who is interested in the care and preservation of historic textiles, banners and flags.

Gwen Spicer is an art 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 artifacts is unrivaled. To contact her, please visit her website.

Thursday, May 28, 2015

A magnet is only as strong as . . .

. . . . its receiving side will allow it to be.  Yes, that is right, a magnet on its own has no power. But in the company of another magnet, or a ferromagnetic material, it will show its pull force.

Metals are grouped by their magnetic behavior, and this is an important factor in determining a magnet's effective pull force. Metals are divided into three groups:
  1. Ferromagnetics which are very/highly attractive
  2. Paramagnetics which are weakly attractive
  3. Diamagnetics which are opposed to magnetic fields

Magnets used in art conservation, spicer art conservation, textile, paper, object conservator

The magnetic system will not function to its full ability if the receiving component is not properly paired with the magnet. This is because the full strength of a magnet can only be reached if the ferromagnetic material it connects with can become magnetically saturated. This means that the receiving material has to be able to hold all the magnet’s “flux” (i.e. the amount of magnetic field passing through a given surface) to utilize 100% of the magnet’s pull force. 

Of the three metals most often magnetized—nickel, cobalt, and iron—iron alloys are the most readily available. Among all elements, these materials can be temporarily magnetized (also referred to as “soft” magnetization) when in proximity to a permanent magnet. (When positioned near a temporary or “soft” magnet, the permanent or “hard” magnet creates the attachment force). But that attraction is lost once the permanent magnet is removed. One common example is a magnetized chain of paper clips: a permanent magnet touches a paper clip, that paper clip becomes magnetized, a second paper clip touches the first and it also becomes magnetized, and so on. Each paper clip has become a soft magnet, but once a paper clip is detached from the chain, it loses its magnetization.

Steel, composed mainly of iron and carbon, offers a wide range of characteristics including high strength, shock resistance, and machineability. Other metals, like manganese, silicon, chromium and molybdenum, are added to alter the properties of the steel to make carbon steel, alloy steel, or tool steel. However, their addition lowers the ferromagnetic properties of the material.

When a sheet of steel is too thin, some of the magnets strength will extend behind the steel, because the steel isn’t thick enough to hold it all. If another ferromagnetic material is placed behind it, just like a paper clip, it too will be attracted and become a soft magnet. In this way the magnetic field can travel to several neighboring layers of ferromagnetic material, increasing the magnetic force as needed. However, if the sheet of steel is thick enough, then the reverse side of the metal shows no magnetic attraction because the steel has become fully magnetically saturated.

The arrows indicate the alignment within the domain walls

Ferrous metal sheet thickness is measured in gauge, commonly found between 30 (thin) and 8 (thick); therefore the higher the number, the thinner the sheet of metal. Specifically, a gauge 8 metal sheet is 0.4 cm (0.1644 inches) thick; a gauge 30 metal sheet is .03 cm (0.0120 inches) thick. 

Gauge measurement refers only to the thickness of the metal sheet, not to the percent of iron alloy or any applied coating; hence one cannot rely on a specific metal’s gauge to ensure that it will have the intended effect. Galvanizing adds to the thickness of the metal and has its own reference tables. Thus, a 24-gauge steel sheet and 24-gauge Galvanized steel sheet have different thicknesses but are equivalent magnetically. 

When using rare-earth magnets, using 22-gauge or thicker is optimal (the minimum gauge steel sheet to use is 24-gauge). Selecting the best gauge of steel sheet for the magnet system is more critical than the overall weight of the mount.

It is also important that when recording your system that along with the shape, grade and size of the magnet, that the gauge and type of the ferromagnetic material (i.e. galvanized steel) is noted. Without these details the system cannot be fully documented or reproduced.

Gwen Spicer is an art 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 artifacts is unrivaled. To contact her, please visit her website.

Thursday, May 14, 2015

Magnet use in art conservation: charts, tables, references & further reading

Magnets are fascinating, but greatly under appreciated because they are so common in our everyday life, therefore it is assumed that they are simple in function and there is nothing more to know. However, the way they work is really complex and there is so much to know about them. When I mention their use for conservation treatments or mounting for exhibition, I usually hear two different responses:

1)  "I don't use magnets, I don't know enough about them and I'm worried I will harm the artifact, OR I'm afraid the magnet(s) won't securely hold the artifact and it may slip or fall."

2)  "I use magnets! But, I don't know too much about them other than I put the artifact against a magnetic surface and then I put a bunch of magnets on the surface (probably more than I have to, but I want to make sure the artifact won't slip or fall)."

My own use of magnets started when I used them to secure an object to a mount. Truthfully, at the time, I knew so very little about magnets, yet I was keenly aware that I needed to be cautious about using any that were too strong for fear of causing damage. The artifact I mounted was a perfect choice because it was sturdy and there was no risk of crushing or marring any surface. The magnets were placed on the mount with metal washers placed inside of the object. A layer of protective Mylar was placed between the magnet and the object.

When choosing the type of magnet to use for this first project, I knew that some magnets were stronger than others, especially that there were these really strong magnets called "rare earth". I knew magnets needed a receiving material - a metal that they could "stick" to; and that some metals created a stronger "stick" than others. But truly what was physically happening within the magnet or the receiving metal was sort of magic. I needed to understand this magic and I needed to be able to create a mount that was SAFE for whatever artifact I was working with. As I began to understand magnets, I realized that the possibilities were endless; mounting textiles, upholstery work, I could think of so many opportunities where I could employ magnets.

Art conservation, rare earth magnets, textile, object, paper conservator, magnets used in conservation
The tufting of a seat using rare earth magnets.

The next project that was perfect for magnet use was to create the tufting on a chair. Disk shaped magnets were the perfect "button" for the tufting site. Strong magnets made a nice tuft as they were strongly attracted to the washer embedded in the seat layers, and the fabric was a reproduction so there was no risk to harming a textile artifact. When the project was completed I was completely hooked on magnets. I had done countless mock-ups in preparation for the tufting, trying various magnet sizes and strengths, pairing these magnets with various sized metal washers, and determining how the fabric layers in between their junction effected the attraction.

Did I make mistakes in the beginning? Yes, of course. For instance, I had no idea that extreme heat would have an impact on how rare earth magnets functioned. So, in an early project I had the great idea of using hot melt glue to affix foam to the magnet, not knowing that the heat of the glue was too hot and made the magnet useless! How sad to find that I had ruined a few magnets before I realized what was going on.

Rare earth magnets used in art conservation, art conservator, Spicer Art Conservation

Also, if I redid some early mounts, I would have ALWAYS put the receiving metal inside of the artifact, never the magnet. Only because reusing rare earth magnets is more desirable than leaving them inside artifacts because of their cost and the environmental damage caused by the mining of these materials. Also, unless the artifact is clearly labeled "magnet within" (or some other kind of warning), it could be placed too near a metallic surface where an attraction could be made, not a pleasant surprise for the person handling the artifact.

Magnets have been around for a very long time. Articles citing artifacts mounted with magnets appear as early as 1988. These were all important early "pioneer" projects, and as art conservation projects using magnets moves forward in time, the complexity of the magnets and materials grows.

To understand and sort out all of the magnet information I had gathered, I began to create charts to reference information I might need again. The charts are listed below and are linked to the image of the chart itself.

- comparison of types of magnets (and their performance properties)
- a list of art conservation projects using magnets (compiled in 2012)

As I began to understand that there are three parts to a magnet system: 1) the magnet, 2) the space between the magnet and the metal receiving material, called "the gap", 3) the receiving metal; I realized that this was more easily understood if diagramed in a cross section.  Below, are the two most requested diagrams from various projects to illustrate each of the components of a magnetic mount and how they work together.

1) Hunzinger chair tufted with the use of Rare Earth magnets:

Spicer Art Conservation, textile conservator, rare earth magnet, re-tufting of chair, upholstery conservation, restoration

2) Hanging system for textiles using "L" bracket

Mounting artifacts with rare earth magnets, Spicer Art Conservation, textiles, objects, paper

Word to the wise:
There are a few things that I have learned that I would strongly advise when using magnets:

1) Don't use hot melt glue. Instead, read this invaluable information about how to safely glue rare earth magnets from the wonderful and knowledgeable people at K & J Magnetics.
2) Think twice if you are tempted to use the products labelled "magnetic paint" to simply paint a wall and then affix magnets to it to hang an artifact.  While this may seem okay when you test it, mathematically there is just not enough strong magnetic attraction created in this type of a system and because of that simple fact, it would be the most likely system to fail.
3) Fingers get easily and painfully pinched when they inadvertently find themselves between two strong magnets that are "jumping" together. If you are using strong rare earth magnets, keep them in containers where they can be separated and handled one at a time - contact lens cases are PERFECT!

Finally, I have compelled a list containing the references for some books or articles written about magnets, especially the aspects of their environmental impact. I have used many of these as a reference in my papers, talks, workshops, or articles. Additionally if you will find a comprehensive list of my magnet articles they can also be accessed on my website, under the PUBLICATIONS tab.

Also, if you have not picked up a copy, my most recently read magnet book is: "RARE; The High Stakes Race to Satisfy Our Need for the Scarcest Metals on Earth" by Keith Veronese.  Get yourself a copy and read it!

Gwen Spicer is an art 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 artifacts is unrivaled.   To contact her, please visit her website.