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As an artisan working in pre-ban ivory and as a supplier of legal pre-ban ivory to folks in the antique restoration trades I have written the following treatise on the methods of working this beautiful material. The legal standing of the material I work in is of paramount importance as is the responsible sourcing of this material. Because this article addresses the working of the material , information relating to the sourcing of the material will not be found here. Parties interested in the origin and sourcing of legal pre-ban ivory may want to visit my Web site. This is the official Web site of the non-profit organization that is chartered with the care and display of my ivory artwork. On the site is a page titled " Legal Ivory " that conveys information relating to the legal and ethical concerns we all understand to be important. The purpose of this treatise is to convey information to fellow craftsmen, artisans and individuals about the unique properties of ivory and to convey methods and procedures for successfully working this material. Pre-ban ivory is a unique material and there are methods of working it that will help one avoid the problems that are all too often encountered by artisans who are not aware of the properties of ivory. It is not necessary to use carbide tools. The material cuts well with a band saw and turns beautifully on a lathe. Files and sandpaper are very useful in the hand working of the material. Dremel cutters and polishing wheels are used by many folks with great success. One should avoid temperature and humidity swings with ivory. Ivory will crack and check if the atmospheric conditions are not stable. It is best to keep ivory at a comfortable human temperature and at 40% humidity. Craftsmen should purchase a humidifier for their work area should they desire to work ivory with success in dry climates. Ivory has grain much like wood but it has the density of a soft metal. The material needs to be aged and seasoned. The material I sell is pre-ban ivory that is well seasoned. We also cut ivory properly - an art that is virtually gone in America today. Ivory grows in rings much like a tree and will crack and break up, over time, oftentimes in the rings it grew in, should it be improperly cut. When ivory is cut there is a great deal of waste and when it is cut properly there is a huge amount of waste. If you buy ivory from us, you can be assured it was cut properly so it will continue to age and season out in a manner that will not lead to the material breaking up over time. This is why we ask what the application of your ivory is. Ivory needs to be cut differently in accordance with the end application of that particular piece of ivory. Ivory is a pleasure to cut, drill, sand, and polish. The following information should be helpful in these areas. When pre-ban ivory is worked it is best to reseal the material, especially the end grain on large pieces, to keep it from checking and cracking. Resealing can be done with a coat of Elmer's white glue set to dry or, most easily, by spraying the ivory liberally with any good clear coat finish. This resealing of the ivory is done when you plan on setting the partially worked ivory to the side for a day or two. After the ivory is sanded and properly polished you will no longer need to reseal the material. If your shop has good humidity it is not so important to reseal the ivory as you progress with your work although I still recommend doing so. The smaller the ivory is, the less important resealing is. Piano keys are thin enough to breathe and never need any sealing. Slabs at 3/16" thick and less are pretty safe and should not need sealing. The same is true with guitar nuts and saddles, etc. but thicker knife handles, gun grips, etc. need attention in these areas. Cue Sticks Inlay slabs for cue stick applications do not need sealing but the round cue parts do. Ferrules are not so critical but joint stock and butt cap stock are prone to cracking and checking in a dry environment. Top-notch cue makers reseal the ivory during the various stages of cue production - usually by applying a thin coat of Elmers’ white glue to the ivory as it spins. In the end, they work this coating off and very soon afterwards apply their finish coat to the cue and ivory. Do not use heat-lamps to help dry the finish as it will cause the ivory round stock to crack. When making a cue joint section where the face of the ivory is purposefully left unsealed it is best to coat this face with a film of CA glue. After it dries one should turn it, and, utilizing sandpaper or a burnishing tool, one needs to burnish the glued surface. This should be repeated 5 times. You will then have a micro-sealed surface of end grain ivory and this will hold up much better to atmospheric changes over the life of the cue stick. If you do not have an atmospherically controlled workshop you may wish to work in the fair weather months when humidity is naturally high across much of the country. Folks living in southern States have little or no problems year-round and folks in the eastern half of the U.S. and west coast areas seldom have problems in the fair weather months. The dry western States are where folks really need a humidified shop as well as folks working ivory in the dry winter months in any area. Swings in temperature can also cause cracking especially if the swings are sudden as when one turns the heat or air-conditioning of a shop off for the night or weekend. The shaping of ivory is accomplished with saws and files. Belt and drum sanders work well but one needs to take care the ivory is not heated up too much in this work as, again, checking can occur especially on the end grain. Many folks use Dremel type cutters to carve and shape the ivory - this is especially helpful when carving figurines and other "in the round" art. Keep ivory dry while working it. Hand sanding is best with a wet-dry type of sandpaper – use it dry. Final sanding is to be done with a used or "dead" 220X paper. When developing a buffed finish you will find a proper buffing procedure will remove all the scratches of a dead 220 sanding and leave your ivory with a mirror like surface. Polishing Polishing ivory is best done by buffing. I recommend utilizing a sewn wheel followed by a floppy wheel. A white jewelers rouge should be utilized. Small parts can be polished with small felt wheels set in a Dremel or drill press. When buffing on a lathe one will find that after a final sanding the rouge can be held to the turning ivory for a melt-on application followed by a burnishing of this rouge into the ivory with a thick piece of felt held to the ivory surface. The ivory will get hot but one develops a "feel" for how hot this can get before one experiences cracking or checking. Turning and polishing on a lathe should be done at about 2000 RPM. Inlays Ivory inlays in wood need special attention. When ivory is thinner than.085", it has a translucency that will cause the inlays to appear darker. To alleviate this feature one should glue white card stock paper to the back of the inlay or apply this paper to the inlay socket that will be accepting the ivory inlay - this will lighten up the ivory to look whiter and more ivory-like in a dark wood. Once inlaid the ivory should be finished as you desire. If the object is lacquered then just lacquer over the ivory just as you do the wood. Use a non-yellowing finish as yellowing will affect the beauty of the ivory long before noticed on the wood. If the object is buffed then you will find the ivory will buff nicely. Also, see my information about glues below. Drilling & Boring Drilling ivory oftentimes causes cracking. Drilling small holes for knife handle rivets, etc. are not a problem but large bore drilling for items like cue joints and butt caps are. When doing large bore drilling, it is best to drill a large pilot hole prior to the final size drilling ( if and when possible and feasible). Boring bars or "gun drills" are better than standard drill bits because they do not develop as much heat. Regular drill bits can be used but one should drill short areas at a time and allow the bit to cool before reentering the ivory. It is the heat and pressure combined that cause the cracking. Lathe boring with a drill bit is best achieved by grinding down the diameter of the bit behind the cutting flukes. This allows for zero friction except where the cutting is being done at the tip of the drill bit. Finished ivory should not get wet, and should be kept from extended periods of direct or indirect sunlight. In the winter or during dry times, some folks keep a film of mineral oil on their knife handles or other finished ivory work and this is not a bad idea. Do not apply a thick coat but rather just a light film as this will keep it from cracking in the dry months. This needs to be done only for a few years after the item is made - by then the material is stable enough to not need it however we recommend that most utility items such as knife handles, gun grips, cane handles, etc. be waxed with Renaissance wax once a year or so. Dyeing Ivory Dyeing ivory can be accomplished by using any of a variety of dyestuffs. The ivory must be brought to a high polish prior to dyeing. The ivory should be "mordanted" by immersing the ivory in muriatic acid for 15 to 20 seconds prior to the immersion into the hot dye. The dye should be hot but not boiling. After removing the ivory from the dye, the color will darken a shade or two. After drying the dyed ivory and letting it cool for an hour or so then rebuff to bring up the high polish again. Be careful not to rebuff to harshly on a firm wheel (sewn) or the color will be buffed out of high areas. This final buffing is best done on a floppy wheel. You can make ivory any color or black and all with a very high gloss that will rival any plastic or acrylic for brightness and boldness of color. Aging of ivory is done through many techniques. The simplest and most commonly used technique is to polish the ivory to a high gloss and then immerse the ivory in a container of hot tea. The tea should be very hot but not boiling. The tea should have a tablespoon of white vinegar per cup of tea to serve as a mordant. Removing the ivory from the tea, one should let cool and then buff. Follow similar cautions as seen in dyeing paragraph above. Ivory can also be put on a cookie sheet in a conventional oven at 150 degrees to achieve crazing and color - experiment at your own risk - best to crack the oven doors at all times. Scrimshanding – the art of ivory engraving – is a simple and easy to learn art form. One needs to polish the ivory to a high gloss by buffing. The ivory is then scored or scratched with a sharp needle or knife point and black India ink is applied to the surface. It takes about 30 seconds for the ink to dry and then the excess ink is wiped from the ivory with a cloth dampened with spit. Water is too watery and oils are too oily - spit works best ! I apply the ink with a q-tip and I prefer Koh-I-Noor brand ink. A good friend of mine does excellent scrimshaw and utilizes only #16 x-acto blades! I prefer a needle point which I fashion on the back end of a #48 drill bit. I hold the bit in a mechanical pencil and a number 48 bit works well as it is the same diameter as the lead for the pencil. Templates can be made from thin plastic found in art and graphic supply stores - this material is known as acetate and I find .010 thickness works well. Bleaching ivory can be achieved in several ways. The best method is to immerse the ivory object in 30% to 40% Hydrogen-Peroxide (H2O2) for 4 days, rinse in warm water, and then set item out to dry. Be aware this is a tricky process. It will end up being very white but it can cause cracking on large parts. Identifying Genuine Ivory Genuine ivory can be discerned from imitation ivory by looking on the end grain of the object in question. Real ivory (elephant) has a herringbone design within the grain itself whereas imitation ivories have not been able to replicate this design. Also, a wood burning kit (like the ones kids receive for Christmas) will melt plastic but not bone or ivory. These tests can help determine if your object is ivory or likely to be ivory but sometimes it is difficult for even the most trained individual to tell the difference between ivory, bone, and imitations. Glues Gluing ivory and finding the right glue can be problematic. Ivory has a creamy texture and, on a molecular scale, it is oily – hence it does not like to be glued. Elmer’s white glue works in many applications. Epoxy glues seem to work well in most inlays into flat grain wood but they tend to push ivory out in side grain applications. CA glues work great if the ivory and its counterpart are very smooth flat surfaces - we just do not know the life span of CA. For most applications I use a 50% PVA resin glue. In most applications one needs to clamp the ivory while gluing because the moisture in the glue will cup and pull the ivory until the moisture in the glue has flashed off. Clamp for 48 or more hours. I usually have the high strength PVA available for sale. Bending and molding ivory has been an age old quest. When ivory is small – as in guitar binding, one can simply soak it in distilled water for a few hours or perhaps a day and then bend it and force it into the application with hand force and then keep it there with clamps until the glue is dry. It is best to utilize hide glue in this type application and best to utilize a scarf joint rather than a butt joint where the ivory strips meet. As to the ancient method for softening, forming, and re-hardening elephant ivory, most of the older books read almost identically to this typical entry from The Scientific American Cyclopedia of Receipts, Notes, and Queries, edited by Albert A. Hopkins, published by Munn & Co., 1892, page 290. Softening Ivory Method #1: In 3 oz. of spirits of nitre, and 15 of water, mixed, put the ivory and leave for three or four days. Method #2: Take a solution of phosphoric acid of 1.130 sp. gr. Put the ivory in this solution, and let it remain until it has a transparent appearance. Take out, wash carefully, dry between soft linen. The ivory will be soft as thick leather. It will become hard if it is exposed to the air, but become soft again if placed in warm water. As concerns method #1, other old books mention that it takes 3 or 4 days for the ivory to soften enough "to obey the fingers." Also note that "spirits of nitre" refers to what we know as nitric acid. I haven't tried this method. Using method #2, I've wrapped a 1/8" thick piece of ivory around a 1/2" diameter rod and hardened it back up again! Phosphoric acid is available through some large hardware stores, and it's also carried by swimming pool supply businesses who use it for cleaning mineral scale off pool and shower tiles. After having thoroughly rinsed the treated ivory in cold soft water, it can then be dried following the more detailed advice given in Fortunes in Formulas, edited by Gardner D. Hiscox, M.E., published by Books, Inc., New York, 1947 (first published in 1907), p. 429. Hardening Ivory To restore the hardness to ivory that has been softened by the above methods, wrap it in a sheet of white writing paper, cover it with dry decrepitated salt, and let it remain thus covered for 24 hours. The decrepitated salt is prepared by strewing common kitchen salt on a plate or dish and standing same before a fierce fire, when the salt loses its crystalline appearance and assumes a dense opaque whiteness. In practice, this is accomplished most easily by just drying the table salt at very low heat in a kitchen oven. Leave the door partly gapped open to prevent getting things too hot and burning the salt. Shape the softened ivory binding or clamp it in order to hold its shape, then totally submerge it in the desiccated salt – I've done this without using the paper wrap and have had no problems. Natural grain and color are restored, and hardness seems to be normal. Tossing the piece in a pot of simmering water quickly softens it up again. Of Interest Ivory and the Elephant: In Art, In Archeology and In Science, George Frederick Kunz, 1916, p.243: Very thin, pliant veneers have been cut into spirals out of a solid block of ivory by means of a feather-edged veneer saw, and some years ago a Monsieur Page patented a process for such work. He produced pieces 17 by 38 in., and asserted that he could make much larger pieces, up to 30 by 50 in. The excessive thinness -- 1/50 in. (note: =.020") -- and the transparency of this veneer renders it not very well adapted for application to wood, etc., as the material beneath would show through to a certain extent. As material for the painter's art, however, it might answer better. Charles Holtzapffel, in Turning & Mechanical Manipulation, 1846 (published 10 years before Kunz was born), Vol. I "Materials," p.154 footnote, while also mentioning this same method of producing thin sheets indicates that they had been somewhat thicker than that referred to by Kunz (Kunz M. Page and Holtzapffel's M. Pape are obviously one and the same person, with the latter spelling probably being correct since it appears twice and predates the Kunz reference): Monsieur H. Pape, of Paris, piano-forte manufacturer, has taken out patents for this method of cutting ivory spirally into sheets. A specimen, 17 inches by 38 inches, and about one thirtieth of an inch thick (note: = .033", slightly over 1/32"), glued upon a board, may be seen at the Polytechnic Exhibition in Regent Street, and M. Pape advertises to supply sheets as large as 30 by 150 inches (note: this must be a misprint, as 150" would exceed the workable length of even the largest tusks; Kunz probably meant 50"). He has veneered a piano-forte entirely with ivory. Similar veneers of ivory are now also cut in England. I would suggest that much thicker sheets could be produced if the tusk section (or at least the material on its outer surface) was first softened before being cut. As support for this idea, Kunz also mentions the impossibly large pieces found in some very ancient statuary (pp.22-23) Enormous pieces of ivory which must have been required by the Greeks in the production of their colossal gold and ivory statues, some of which were forty feet or more in height, the face, hands, and feet being of ivory, and even the large size of some of the consular and other diptychs that have come down to us, have raised the question, how did the ancients secure pieces of ivory of sufficient size? In our day, with the processes now in use, this would not be possible. Hence it has been conjectured that they possessed some lost art for welding together separate pieces of ivory. In the late Latin treatise on the arts of the Romans, belonging to the tenth century, and which passes under the name of Eraclius, the following directions are given: "Take sulphate of potash, fossil salt, and vitriol; these are ground up with very sharp vinegar in a brass mortar. Into thix mixture the ivory is placed for three days and nights. This being done, you will hollow into a piece of wood as you please. The ivory being thus placed in the hollow, you direct it and will bend it to your will." But this recipe as well as others given by various ancient writers do not give satisfactory experimental results. In some instances tusks of quite exceptional size have furnished very large flat pieces of ivory, it is regarded as possible, if not probable, that the ancients cut large cylindrical pieces from the median part of the tusk, split these cylinders at a given point, softened them by some process, and then flattened them out, thus securing a piece as broad as the circumference of the tusk. This theory was advanced by Mons. Quatremere de Quincy. Steeping in vinegar and almond oil does really render ivory ductile to a certain extent. While it can be decomposed by caustic alkalis, it cannot be recomposed. When working with ivory, utilize proper safety precautions: eye protection, respirator, etc. Ivory Care There are many old wives' tales on how to care for ivory, and most are simply not effective or applicable. Ivory piano and organ keys can be cleaned with milk, followed by a wiping down with bathroom alcohol. Piano keys are the only thing I can think of that could best utilize the application of milk as a cleanser. Knife handles and gun grips and other smooth ivory objects can best be cleaned with alcohol. Q-tips are good for this and even a toothbrush. Once cleaned I recommend a waxing with a good paste wax. I like Renaissance wax from England. While expensive, one jar will wax everything a man owns for the rest of his life. Carved items, where dirt has worked itself into recesses, can be cleaned with a soft toothbrush and alcohol. If the dirt is stubborn one can use toothpaste or soap and warm water however the polish is going to dull down with this method and so it is recommended only for those who can re-establish the polish via buffing. A light buffing on most items will bring the luster back quickly and with ease – proceed with caution. Bleach (chlorine) can be used to clean ivory but it is tricky in that it eats away at the ivory. Application and scrubbing needs to be done quickly in warm water and then rinsed thoroughly in a tub of vinegar water, which stops the bleaching action. Be aware the bleach will also whiten the ivory and will destroy the polish so you will lose some or all of the aged patina the object holds and you will need to re-polish the object. Bleaching has its place in but it is generally not recommended . There are many people who believe that oils are good for ivory. Never use olive oil on ivory as it will permanently discolor the material and attract dirt and, eventually, bacteria. Never use oils in the working of ivory. Among knife makers there is an old wives' tale that speaks of immersing ivory in milk or oils before working it - save yourself a great deal of grief by discarding this crazy idea and never letting it re-enter your head. After a smooth ivory object is completed and polished, a thin coating of mineral oil cna be applied. Mineral oil is sold as a laxative in most drug stores and comes in differing viscosities. I recommend thin or light mineral oil as opposed to heavy or thick. This is best for knife handles and gun grips and is especially applicable to newly worked ivory that is in a dry climate. It is often applied to such items during the colder months in northern states. It is best to think of keeping a light film of this oil on the ivory just as one would keep a thin film of oil on a gun to keep it from rusting. This is not something that is needful forever. I usually recommend such treatment for the first few years after the item is made and then one can switch over to the Renaissance wax which is not as messy. Keep in mind - most folks need only concern themselves with this if they are in dry climates. When shipping ivory one can put a film of oil on the ivory and then wrap it in Saran wrap . This is a good idea as shipping involves temperature and humidity swings beyond measure - it is cold and dry at 30,000 feet in a cargo plane full of postal. Keeping moving air and direct sunlight away from ivory is a ideal. A curio cabinet is a good place to display ivory items as there is no moving air. In dry times one can place a cup of water in the cabinet to bring up the humidity with ease. Keep in mind that all of these precautions are for large pieces of ivory, such as knife handles, gun grips, etc. Items like pool cues are far less susceptible to needing this care because the ivory has not been buffed but has been sealed over with a clear finish - thus protecting it from the open air. Ivory knife handles in particular are subject to cracking from dry air moving over their surface. It is best to display knives in a sealed display case so they are not subject to air movement. Given the precautions, one would think ivory is not a desirable material, but rather the opposite is true. Ivory, with minimal care, will give you long lasting beauty and joy. Given its longevity you can expect a well-made ivory item to last indefinitely. Frequently, archaeologists unearth ivory items that date back to the dawn of civilization. The oldest known piece of artwork created by man was made of ancient mammoth ivory. All cultures throughout history have utilized and treasured ivory. The Romans considered ivory to be the noblest of all materials on earth.
David Warther |
