IVORY. - The modes of polishing objects made of this useful and ornamental substance, differ according to the nature of the works; and although the remarks here offered refer especially to the ivory of the elephant, that of the tusks of other animals, also the corosos or vegetable ivory, and bone are treated nearly or quite the same, when applied to similar uses.
1. - Turned Works with plain surfaces may in general be left so smooth from the tool as to require but very little polishing, a point always aimed at with superior workmen by the employment of sharp tools. In the polishing of turned works very fine glass paper or emery paper is 1st used, and it is rendered still finer and smoother by rubbing two pieces together face to face; 2ndly, whiting and water as thick as cream is then applied on wash leather, linen, or cotton rag, which should be thin that the fingers may the more readily feel and avoid the keen fillets and edges of the ivory work, that would be rounded by excessive polishing; 3rdly, when the work feels smooth, or to hang less to the rag than at first, the work is washed with clean water on the same or another rag; 4thly, it is rubbed with a clean dry cloth until all the moisture is absorbed, and lastly a very minute quantity of oil or tallow is put on the rag to give a gloss.
Scarcely any of the oil remains behind, and the apprehension of its being absorbed by the ivory and disposing it to turn yellow, may be discarded; indeed the quantity of oil used is quite insignificant, and its main purpose is to keep the surface of the ivory slightly lubricated, so that the rag may not hang to it and wear it into rings or groovy marks. Putty powder is sometimes used for polishing ivory work, but it is more expensive and scarcely better suited than whiting which is sufficiently hard for the purpose.
2. - Turned Works consisting of many parts are best polished separately, as they are then more accessible, and the whiting and water do not penetrate and clog the joinings of the several parts, and prevent their easy separation. Accurate workmen frequently polish screw threads, in order to make them move the more easily, and to endure the longer without wearing loose; this is sometimes done with screws in ivory and the woods, as well as those in the metals, and is to be highly recommended.
3. - Turned works ornamented with the eccentric chuck, revolving cutters, etc. also require to be cut with exceedingly sharp tools, in order that but little polishing may be necessary.
The polishing of irregular surfaces is generally done with a moderately hard nail brush, supplied with whiting and water, and lightly applied in all directions, to penetrate every interstice; after a period the work is brushed with plain water and a clean brush, to remove every vestige of the whiting. The ivory is dried by wiping and pressing it with a clean linen or cotton rag, and is afterwards allowed to dry in the air, or at a good distance from the fire; when dry a gloss is given with a clean brush on which a minute drop of oil is first applied.
It is better to do too little polishing at first, so as to need a repetition of the process, rather than by injudicious activity, to round and obliterate all the delicate points and edges of the works, upon the preservation of which their beauty mainly depends.
4. - Superior flat works are accurately filed and scraped, then cleaned with fine glass paper folded around a square stick, afterwards with whiting also on a stick of deal planed very flat and square and used as a file; some workmen cover the wood with one or two layers of flannel or cloth, but the naked wood, although somewhat tedious, will produce more exact surfaces and better defined edges.
5. - Common Filed and Carved Works are finished - 1st, with Trent sand and water on flannel or a brush; 2ndly, scraped Flanders brick used in the like manner; 3rdly, wet linen or woollen rag with powdered chalk, which soon rubs down smooth, and to the condition of ordinary whiting.
6. - Razors and Knife Handles are most generally finished by shaving or scraping, and 2ndly by buffing them on the wheels, as more fully explained under the head Tortoiseshell; but the following methods are by some preferred.
7. - Common Razor Handles. - These are sawn out and filed, then scraped with an old razor blade, called a shaving blade; two razor handles or scales are then held at the one end in a pair of clamps in the vice, and rubbed lengthways - 1st, with chalk and water on felt or cloth, which cuts very quickly; and 2ndly with whiting and water for the finish.
8. - Best Razor Handles. - Two scales are slightly rivetted together and buffed, 1st, on a buff wheel fed with Trent sand; 2ndly, buffed with rottenstone; 3rdly, they are handed up or polished with the naked hand and rotten-stone. Other workmen entirely omit the rottenstone, which requires oil, and conduct the work with chalk and whiting, so that water may be used throughout the work.
9. - Umbrella and Parasol Handles, and many similar pieces are polished first with sand, and then with whiting, on cloth wheels consisting of several circles of thick cloth or felt, clamped between two smaller disks of wood; the cloth projects about an inch around the margin to make a soft elastic edge.