Sandpaper

“ It must always be kept in mind that a surface which has been sandpapered has become “gritty,” i.e. the fine sand has come off and is more or less imbedded in the wood. Consequently sandpapering must not be done until all tool work has been finished, as the grit will take the edge off the best tool, and the finer the edge the more quickly will it be ruined.
Fig. 48. An Exercise involving the Use of Sandpaper
Again, a sandpapered surface is always a scratched surface, and the finest of scratched surfaces cannot compare with the perfectly smooth, satiny surface produced by a sharp plane. ”

“ This part of the work calls for good judgment, for unless sandpapered enough, there will be places which will show when the finish is spread on the work, though they may have been invisible before. No one can tell as well as the workman himself when sufficient sandpapering has been done, though it may be evident to any one who knows the signs whether or not the work has been done judiciously. Upon a coarse job it is usually allowable, and sometimes desirable, to sandpaper across the grain, especially if the work is to be painted. ”

“ Mouldings, clips, bolt heads, difficult places to work up to, everywhere bespeak the same thorough touch of the sandpaper. There are many sharp edges about a vehicle which may be denuded of pigment at a single rasp of the paper. Such parts require a good measure of protection, otherwise flaking and chipping of the paint and varnish must naturally follow. The painter may well strive to make the work of sandpapering an exact operation—exact as to thoroughness as applied to all parts of a surface, and exact as to a uniformity of results. ”

“ It is for the one who knows, that all work should be done—not for the casual observer—and these apparently [Pg 124] insignificant details, rather than the part of the work which may seem of more importance, form the basis by which one workman judges the work of another. In nothing do small things count more than in making or destroying a workman’s reputation.
Fig. 97.—Use of Sandpaper upon a Broad Surface.
(B.) Keep the sandpaper dry, and stored in a dry place, as moisture softens the glue so that the sand may be easily rubbed off. ”

“ The body then passes to a skilled workman, who applies the final coats of colour. For facing mouldings and for corners throughout all stages of the processes, dry sandpaper takes the place of pumice and water. All stopping on the chassis, the first lead coat on the bonnet, and all coats of paint on the wheels, are sandpapered dry. Sometimes a third of a man’s time may be taken up in sandpapering alone. ”

“ The wood should be cut out with a knife so as to leave the corners sharp on the narrow bands. The portion cut out should be a semi-circle and can be sanded by making a spindle a little smaller than the distance between the bands and fastening sandpaper on the spindle. Place in the lathe and hold the spiral on the sandpaper cylinder at an angle so that the spiral will fit. Turn gradually and the sandpaper will smooth up the portion between the bands and true it up. At the ends where the grooves are smaller, use a smaller stick around which sandpaper has been wound and work out by hand. ”

“ Sandpaper did not come within their purview. It had no recognised use in hospital. Therefore it did not exist. But, observing that a succession of metal pudding-basins would be an insupportable prospect without sandpaper, I laid in a stock of sandpaper, paying for the same out [Pg 60] of my own private purse. It was a cheap investment. Never have earnings of mine been better spent. Moreover, having once hit on the notion of giving myself a lift illegitimately, so to speak, I added to the smuggling-in of sandpaper a secret purchase of soda. ”

“ After the construction work and nailing is completed, the box may be sandpapered carefully, rubbing in the direction of the grain, and being careful not to round off the edges unduly. The oversandpapering of woodwork marks the work of the careless novice. The box should be handled as little as possible while the metal trimmings are being fitted, and, before the finish is applied, should be gone over lightly with sandpaper to remove dirt. ”

“ Some walls will need a second coat of lining paper and another sandpapering, before they are smooth enough for anything like a fine job. If the owner refuses to stand the expense of putting on lining paper, glue size the wall, and when dry, knock off the prominent grains of sand with sandpaper and knife in plaster paris putty on the rough places. ”

“ After this another coat of Shellac Varnish is applied, both to the front and the back of the wood panel. Three hours after that, it can again be lightly sandpapered, and then it is ready for painting. The sandpaper is essential because it roughens the surface and forms a bond between the pigment and the wood. If you paint on a highly polished surface, whether it be glass, metal, wood or canvas, there is very little bond between two glossy coats, and the chances of peeling are very great ”

“ If this is not available, any other means may be employed to saw the dowels into disks 1⁄8” or 3⁄16” in thickness.
[Pg 46]
Lay a piece of sandpaper on a flat surface and rub the checkers on this to remove saw marks. Two grades of sandpaper give a better finish than one.
To play the game, it is necessary that there should be two colors of checkers. Some woods present sufficient difference in their natural colors to serve this purpose, but it is generally better that one set at least should be artificially colored. ”

“ Instead of using the oilstone an easier, tho less perfect, way to flatten out the burr on the edges is to lay the scraper flat on the bench near the edge. The scraper steel is then passed rapidly to and fro on the flat side of the scraper, Fig. 157. After that the edge should be turned as before.
Fig. 157. Resharpening a Cabinet-Scraper: Flattening the Edge.
Sandpaper. The "sand" is crushed quartz and is very hard and sharp. Other materials on paper or cloth are also used, as carborundum, emery, and so on. Sandpaper comes in various grades of coarseness from No. 00 (the finest) to No. ”

“ By using sand paper in this manner, every grain of the sand is brought into contact with the work; furthermore, a small area of sand paper is brought into contact with the work, and the wood fibre can fly off and not lodge in the sand paper; while at the same time the angles of the grains of sand or glass are presented more acutely to the work, and therefore cut more freely and easily. Hence the sand paper lasts much longer, because a given pressure is less liable to detach the sand from the paper. ”

“ After merely mentioning the pneumatic rammer for forcing sand into foundry moulds, we pass to the pneumatic sand-papering machine, which may be described briefly as a revolving disc carrying a circle of sand-paper on its face revolved between guards which keep it flat to its work. The disc flies round many hundreds of times per minute, rapidly wearing down the fibrous surface of the wood it touches. When the coarse paper has done its work a finely-grained cloth is substituted to produce the finish needful for painting. ”

“ For polishing, they have sand-paper and emery-paper purchased from the whites; but as these are expensive, they are usually required only for the finishing touches, the first part of the work being done with powdered sandstone, sand, or ashes, all of which are used with or without water. At certain stages in the progress of the work, some articles are rubbed on a piece of sandstone to reduce the surfaces to smoothness; but the stone, in this instance, is more a substitute for the file than for the sand-paper. ”

“ Shading may be done in various ways. Lines may be engraved and filled up with a glue cement, or hatchings may be drawn with a scorching solution, or the wood may be burnt with hot sand. The sand is made hot in an iron pot, and the piece to be darkened inserted. Or it may be scorched with a hot iron or spirit or gas flame. The simplest way is with the poker used in poker work." In England the sand is heaped upon a metal plate which is heated underneath. The veneer is held with tweezers and pushed into the sand, the gradation of heat giving gradation of tone. ”

“ The fine sand material, though possessing quite a smooth surface, is like a sponge in its power of suction, and, when used, is unrolled and pressed over the pulp by a machine.
This done, the plate containing the paper is moved to an adjoining part of the building, which is roofless, and is there exposed to the rays of the sun, which finishes the drying process and gives a beautiful glaze or polish to the paper. Nothing so well dries the paper as the sun, as we have proved by frequent experiments. After the sun, fire is the most efficacious agent ”

“ Sand and emery papers are produced by coating a stout paper with glue, and then sprinkling sand or emery-dust upon the surface. Man’s skill has devised for this purpose an ingenious machine. This first coats the paper with glue from a revolving brush, which plays over the surface of melted glue in a steam gluing-pot below. Having accomplished this result, it softens the glue with a spray of steam, and sifts the sand upon the surface, all surplus sand dropping110 into a box below as the sanded or emery-surfaced paper passes over a roller. ”

“ The process of boiling short 2 feet logs of wood in a digester under a pressure of 20-50 lbs. has long been known. The wood after boiling is partly washed and then worked up into pulp by the usual mechanical process. The wood is easily ground and yields pulp containing long fibres which in their physical properties closely resemble those of pure wood cellulose, but the original constituents of the wood are present almost unchanged, just as in mechanical pulp. The product obtained by grinding is a very tough flexible material of a brownish yellow colour, and the paper is known as Nature brown. ”

“ The object being merely to dry the pulp, a very heavy web can be obtained, since the water leaves this pulp very freely. The wood pulp thus obtained is perfectly clean, of a soft, white spongy fibre, and a greater portion of it is mixed with a small proportion of rag pulp and worked into book and fine printing papers. Sometimes the wood pulp is used alone or mixed with white paper shavings for book paper. The fibres are rather deficient in strength, but as a material for blotting paper they are said to be unsurpassed, while the wood paper is much liked by printers. ”

“ Then a second, and even a third sand of increasing fineness is to be applied. The next substance is emery of progressive degrees of fineness, after which tripoli is employed; and the last polish is given with tin-putty. The body with which the sand is rubbed upon the marble, is usually a plate of iron; but for the subsequent process, a plate of lead is used with fine sand and emery. The polishing rubbers are coarse linen cloths, or bagging, wedged tight into an iron planing tool. In every step of the operation, a constant trickling supply of water is required. ”

“ By combination with a mixture of nitric or sulphuric acid and water, soft paper becomes parchment-like and very hard. This requires careful experimenting, for its success depends on the quality of the acid and the texture of the paper. Very remarkable results have been obtained from this, such as material resembling ivory, horn, and tortoise-shell, in large blocks.
Waste-paper is so common and cheap that papier-mâché can always be made anywhere. It is well adapted to close cracks in wood, walls, or elsewhere; and for those who wish for an employment or amusement, it affords endless facilities. ”

“ The steps subsequent to cooking chemical pulps of all kinds are similar. After emptying the digesters, the soft, discolored mass of fibers is washed and bleached. The yield of cellulose fiber is close to fifty per cent of the air-dry weight of the wood. The shives and undigested particles are removed by screening, and the pulp is either run out like ground wood on wet machines, or made up into rolls, or 36sheets, on a paper-machine. The soda pulp is shipped in rolls and the sulphite in sheets, as this is the most favorable form in which to handle them at the paper-mill. ”

“ Only a little need be said, and that of the most modern operations, of finishing, of the grinding, tarnishing, and polishing, ornamentation with gold-leaf and platinum-foil, luster, and enamel coloring, etc. One of the most noteworthy of these operations is that of tarnishing by the centrifugal sand-blast. The objects to be treated by this process are fastened upon revolving wooden pegs in the walls of a wooden box; the sand is introduced into the middle of the box, and is thrown by rapidly rotating fans against its sides and against the glass figures. ”

“ Whatever material may be used for making into paper it has to undergo stages of preparation which can be divided into removing all foreign matter and dirt, reduction to fibrous state, bleaching, beating, and lastly converting what is the pulp into paper. If the material has already been manufactured, as in the case of rags, ropes, sails, sacking, and other textiles, the first process is somewhat simpler than in the case of really raw materials, such as esparto, bamboo, or wood. ”

“ The value of Esparto for the manufacture of high-class printing and medium quality writing paper is well known. This material has qualities which cannot readily be obtained from other fibres, such as rag and wood pulp. It is chiefly used in papers required for lithographic printing, books, and art illustration, since it gives a sheet having a good surface and one which is soft and flexible.
The grass is obtained from Spain, Morocco, Algeria, Tunis, and Tripoli, in which countries it grows wild, requiring very little cultivation. ”