INDIA-RUBBER VARNISH.
A. Ford, of London, has obtained a patent for making solutions of India-rubber and gutta-percha, which solutions can be used for water-proofing as a varnish. The India-rubber or gutta-percha, is dissolved in warm turpentine or naptha. The turpentine, or naptha, is prepared by mixing a caustic alkali, such as potash, in it—one pound to the gallon—then agitating them in a suitable vessel, and allowing them to stand for about three days, when a dark colored residuum is found at the bottom. The clear liquor is then poured off and used for dissolving the India-rubber. It is stated that this makes a very beautiful varnish.
A patent has been obtained by Alex. Parkes, of Bury Port, Wales, for a preparation of oils similar in its nature to the improvement of Mr. Daines. He treats oils with the chloride of sulphur, which changes their character, rendering them similar to vulcanized India-rubber, and insoluble in mineral naptha and sulphuret of carbon. He heats about 2 parts by weight, of the chloride of sulphur with 8 parts, by weight, of oil, up to about 250°, when the combination of the two is effected. This vulcanized oil, it is stated, can be mixed with gutta-percha or India-rubber, to cheapen the manufactured articles made from these materials. This, apparently, is also an important invention.
Mr. Parkes has also taken out a patent for a varnish made of gun cotton dissolved in alcohol, or anysolvent of gun cotton. This varnish is transparent, and he applies it to coat silk, sewing cotton, thread, leather, plaster, wood, &c., to render them water-proof. Gun cotton dissolved in chloroform is a well known varnish.
This article, in the form of purified white India-rubber, has been patented in England, for making artificial teeth, gums, and palates. By its adoption, many advantages hitherto impossible to be attained, have been introduced. The adhesion is complete, it can be moulded with perfection, to suit every inequality of the gums and teeth, and supplies an artificial periosteum, as it were, to the teeth, when become painful by the wasting away of the gum, added to these is the elasticity of the material, which completely obviates the inconveniences that arise from any motion with artificial teeth, as made by other means.
TheMoniteur Industrielmentions an ingenious method of obtaining fine emery paper for polishing metals. Strips of paper coated with fresh starch-size are hung on ropes at different altitudes in a small room, which is afterwards carefully closed. A quantity of fine emery is then blown in by means of a ventilator, through an aperture left for the purpose, by which means a dense cloud of emery dust fills the room, but only the finest particles rise in the air to a sufficient height for them to be deposited onthe upper slips; those of the second row receive a somewhat coarser sort, and so on, while such particles as are too heavy, and therefore too coarse for delicate polish, fall to the ground at once. Thus emery paper of different degrees of fineness may be obtained by a single operation, and sorted with mathematical certainty.
At a recent meeting of the Society of British Architects, J. B. Daines stated that by subjecting eight parts (by weight) of linseed oil and one part of sulphur, to a temperature of 278°, in an iron vessel, he obtained a species of paint possessing singularly preservative properties. Applied to the surface of a building with a brush, it effectually keeps out air and moisture, prevents deposits of soot and dirt, and preserves the beauty of the stone, wood, or brickwork to which it is applied. It has long been known that a portion of sulphur can be dissolved in oil, but until recently such a composition, as a paint or varnish, has attracted no notice; in fact, its preservative and impervious qualities when dry, were unknown. It is well known to chemists that sulphur, (the substance employed to givebodyto the oil,) is unalterable in the air, and is not acted on by moisture; hence its quality as a preservative for coating the outside of structures exposed to the weather. It is capable of preserving plaster of Paris figures exposed to the air, also monuments, and buildings of the brown freestone, which are liable to detrition, from the action of the weather. It is stated that it improves the colorof the stone to which it is applied, as well as preserves it; therefore it is a most useful paint, and deserves to be very generally employed.
Mr. C. Goodyear has recently taken out a patent in England, for a new compound, composed of India-rubber and coal tar vulcanized with sulphur. Coal tar is heated in an open boiler until it acquires the consistency of melted rosin, when it is mixed with India-rubber, in proportions which may vary according to the character of the material to be produced for a specific purpose. It is mixed with sulphur and then heated to vulcanize it.
Dissolve two pounds of strong glue in one quart of water, in a glue kettle, or in a water bath; when the glue is entirely melted, add little by little to the amount of ten ounces of strong nitric acid. This addition produces an effervescence due to the disengagement of hyponitric acid; when the whole of the acid is added, remove the vessel from the fire and leave it to cool.
Glue thus prepared, kept in a stopped flask, will remain good for two or three years.
A series of interesting experiments have just been concluded at the Birmingham Waterworks, relative to the strength of gutta-percha tubing, with a view to its applicability for the conveyance of water. Theexperiments were made (under the direction of Henry Rolfe, Esq., engineer,) upon tubes three-quarters of an inch in diameter and one eighth of gutta-percha. These were attached to the iron main, and subjected fortwo monthsto a pressure of 200feet head of water, without being in the slightest degree deteriorated. In order to ascertain if possible, the maximum strength of the tubes, they were connected with the Water Company’s Hydraulic Proving Pumps, the regular load of which is 250 lbs. on the square inch. At this point the tubes were unaffected, and the pump was worked up 337 lbs., but to the astonishment of every one the tube still remained perfect. It was then proposed to work the pump up to 500 lbs., but it was found that the lever of the valve would bear no more weight.
Theutmost powerof the hydraulic pump could not burst the tubes.
The gutta-percha being somewhat elastic, allowed the tubes to become slightly expanded by the extraordinary pressure which was applied, but on its withdrawal, they resumed their former size.—London Mechanics’ Magazine, Vol. LI.
Two pounds of tallow, a pound of hog’s lard, a half pound of turpentine, and the same quantity of bees-wax are melted together in an earthen pipkin. The boots and shoes are dried and warmed, and the composition is well rubbed into them with a piece of tow dipped into it; the articles being held near a hot fireuntil they have imbibed as much as they can take up. This mixture is used with very good effect by sportsmen.
Another mixture for the same purpose, which is much used by fishermen, is applied in the same way. It consists of a pound of bees-wax, a half pound of rosin, and the same quantity of beef-suet.—Morfit.