The bent mountings are designed for molten metal, such as brass or copper and are supplied with either clay, graphite or carborundum tubes.
The inner and outer surfaces of the wall were both painted with two coats of stiff cement grout neat, and in addition the inner surface was rubbed smooth by carborundum brick.
The carborundumbrick was selected on account of its hardness.
The object was to rub this interior surface with carborundum before the surface of the concrete had taken its final set.
It was of interest to find whether carborundum possesses the quality of phosphorescence.
The difficulty is that the binding material gives way, and the carborundum is slowly thrown off after some time.
To make such a button of carborundum crystals I proceed in the following manner: I take an ordinary lamp filament and dip its point in tar, or some other thick substance or paint which may be readily carbonized.
Some effects, which I had not observed before, obtained with carborundum in the first trials, I attributed to phosphorescence, but in subsequent experiments it appeared that it was devoid of that quality.
When the powder is used I have found it best to proceed as follows: I make a thick paint of carborundum and tar, and pass a lamp filament through the paint.
When the metal disc is covered with carborundum crystals, the film is far more intense, and snow-white.
A carborundum coating seems to be more durable than other coatings, not only because the carborundum can withstand high degrees of heat, but also because it seems to unite with the carbon better than any other material I have tried.
With a diamond, carborundum or zirconia button the photosphere can be as much as one thousand times the volume of the button.
The only difficulty which I have experienced in its use in connection with these experiments was to find some binding material which would resist the heat and the effect of the bombardment as successfully as carborundum itself does.
Carborundum can be obtained in two forms--in the form of "crystals" and of powder.
The sponge becomes saturated with water because of the capillary action of the carborundum upon the water.
Among these are, the writing diamond, the carborundum or abrasive pencil, the cutting-wheel, and etching by means of hydrofluoric acid.
A rod of carborundum composition may be ground or filed to a point, and this forms a very useful pencil for general work.
If a pointed brush is necessary, the point may be ground on an ordinary grindstone or carborundum wheel by pressing the loose end of the spun glass against the grinding wheel with a thin piece of cardboard.
The rough shaping is done with coarse carborundum or emery, and successive stages are carried on with finer and finer material.
This tube may be held in an American hand-drill, but a mixture of carborundum or emery and water is supplied to the rotating end.
Carborundum is produced by fusing carbon and silicon by means of a huge electric arc, the result being a mass of beautifully colored crystals which are harder than any known substance except diamonds.
Carborundum is rapidly taking the place of emery for abrasive purposes.
For this, a very little fine flour of emery or carborundum is the best and quickest.
In general, only a little grinding will be required, and one small pinch of carborundum or emery will be ample.
When the core is complete, more of the carborundum mixture is shovelled in and tramped down until the furnace is heaping full.
Illustration: The Furnace-Room, where Carborundumis Made.
When the core becomes white hot it causes the materials surrounding it to unite chemically, producing the carborundum crystals.
At the centre of the furnace, surrounding the core, there remains a solid mass of carborundum as large in diameter as a hogshead.
To return to carborundum: when the furnace has been cooled and the walls torn away, the core of carborundum is broken open, and the beautiful purple and blue crystals are laid bare, still hot.
Illustration: The Interior of a Furnace as it Appears after the Carborundumhas been Taken Out.
When the fused mass of the carborundum furnace is broken up there is found surrounding the carborundum core a similar substance though not quite so hard and infusible, known as "carborundum sand" or "siloxicon.
Carborundum or crystolon is also made up into refractory ware for high temperature work.
They got carborundum as early as 1885 but miscalled it "crystallized silicon," so its introduction was left to E.
In the foreground are the fused masses of the product] [Illustration: Courtesy of the Carborundum Co.
The production of aluminium in Switzerland and Scotland, carborundum and calcium carbide in the United States, and soda by the Castner-Kellner process, began to be conducted on an immense scale.
A trough is filled with water to catch the dust from the carborundum wheel, while the knives are being ground.
The flesh side is finished by fluffing it on the emery or carborundum wheel (Fig.
Knives are often roughened owing to the carborundum wheel wearing irregularly.
In order to sharpen the blades of the cylinder, a carborundum wheel is fixed in close proximity, its position being indicated in the drawing by the wheel cover (67).
Carborundum is used as an abrasive, that is, as a material for grinding and polishing very hard substances.
Surrounding this core is a layer of crystallizedcarborundum C, about 16 in.
Outside this is a shell of amorphous carborundum A.
Emery, carborundum and alundum wheels are developed from the grindstone of the distant past.
The crystals of carborundum thus produced require seven horse-power hours for each pound; in hardness they are excelled by the diamond only.
This alloy is so hard that it cannot be machined or drilled by ordinary means; it must be treated by emery or carborundum wheels.
Its successors of to-day, the carborundum wheel especially, can be of varied shapes, and transfer these to metal with celerity and economy.
Emery either spread on paper, or glued upon a wheel, grinds with an accuracy and speed new to art; and all that emery can do is outdone by carborundum and alundum, which slice away metal as if chalk, be its hardness what it may.
Carborundum wheels are replacing lathes as a means of finishing axles, piston-rods and rolls; their accuracy is unsurpassed, while they demand but one third the time needed by a steel tool.
This specimen was shipped to Denver and polished there, and required many days of grinding with carborundum and diamond dust.
By a process of grinding with carborundum and diamond dust, then rubbed with leather buffer.
The only difficulty which I have found in its use in connection with these experiments was to find some binding material which would resist the heat and the effect of the bombardment as successfully as carborundum itself does.
A carborundum stone for rapidly re-covering the shape of a chipped or blunt tool.
Carborundum paper, made like emery paper, is now largely used in place of garnet paper in American shoe factories, and finds a market in other directions.
In such a furnace as that above described the charge weighs about 14 tons, the yield of carborundum is about 3 tons, and the expenditure of energy about 3.
This can be done by using a half-inch drill which has been ground on a carborundum stone to a conical point the proper length.
With a file and carborundum stone, they are edged and shaped into blades as sharp as knives.
Carborundum is harder than any gem material but diamond.
Most hardware stores have specimen crystals as attractive advertisements of carborundum as an abrasive material, or the Carborundum Co.
It will scratch sapphire and ruby, which are rated 9 in hardness, hence we may call carborundum 9-1/2 if we wish.
Some of the softer materials, such, for example, as turquoise, are rubbed down on a fast flying carborundum wheel of similar type to those used in machine shops for grinding steel tools.
The carborundum wheels have the grains of carborundum cemented together by means of some binding material and this gradually crumbles, exposing fresh, sharp cutting edges.
So-called carborundum bricks have been put on the market, which have a coating of carborundum and clay fired on to the firebrick, and which are said to have a greatly extended life for certain purposes.
It is probable that the carborundum gradually decomposes in the firing, leaving a thin coating of practically pure silica which forms a smooth, impervious and highly-refractory facing.
Then the sawed face is ground as smooth as possible on carborundum wheels of different grits.
The piece is first cut with either a diamond or carborundum saw.
Like carborundum and aluminum, this product could not have been produced in commercial quantities in advance of a means for producing electricity in enormous volume.
While carborundum has already a large place as a commercial product, there is no doubt but that the uses to which it will be put will vastly increase as time goes on.
Imagine the load that a string of horses two miles long could draw, if all were pulling together, and you will get something of an idea of the energy expended during the burning of one of these carborundum furnaces.
These carborundumcrystals are next crushed under rollers of enormous weight, after which the crushed material is separated into various grades for use in making grinding-wheels of different degrees of fineness.
The crude materials used in the manufacture of carborundum are, sand, coke, sawdust and salt; the compound is a combination of coke and sand.
Surrounding the core for a distance of ten or twelve inches, radiating in every direction, beautifully colored crystals of carborundum are found, so that a single furnace will yield over 4000 pounds of this material.
It is quite a good thing the snow put the party off, for it is the funeral day of the young Prince Arusigawa, and also we were not nearly ready with the cutting-machine--the automatic carborundumapparatus is still far from complete.
The success met with in making carborundum led to the devising of a method of manufacturing artificial graphite in the electric furnace.
In the past few years, lapidaries and gem-workers have learned to cut stones and gems with steel disk-wheels, the cutting edges of which are furnished with carborundum or emery powder or insets of diamonds.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "carborundum" in a variety of sentences. We hope that you will now be able to make sentences using this word.
