By reference to page 254, Vol. 8, Scientinc American, our readers will perceive that a patent was granted to Charles Goodyear and Robt. Hearing, assignors to Charles Goodyear of New Haven, Ct., for an improvement in the mode of manufacturing goods from india rubber, gutta percha, & c, and a patent was granted in England, for the same process in 1851. The following abstract of the specification, will be interesting to many ot our readers. It contains all oi importance embraced in the patent: u The improvements made are in the moulds which give form to the vulcanized rubber. & c, heretofore metal moulds have been used without good results. The invention consists in using or employing sand pulverized soapstone, plaster, or some similar granular, or pulverl zed substance, and when put together form porous matter, or moulds made oi porous substances, to sustain and keep the form of moulded articles composed of caoutchouc or its corct-poundSj and other gums susceptible oi vulcanization during the process of heating or vulcanization. We take articles composed of compounds of caoutchouc or other gums susceptible of vulcanization in the green state. We cause them to be pressed or otherwise formed into the exact shapes which they are required to have, after being vulcanized ; we then cover the surface of the articles with pulverized soapstone, or plaster, or other similar non-adhesive powder. We then place the articles in a box filled with sand, the finer the sand the better, or pulverized soapstone, or other similar equivalent granular or pulverized matter, so that each article shall be completely surrounded and covered by the sand or pulverized soapstone or plaster, & c, and imbedded in the same, and thereby sustained when it is desired to give a very smooth surface to the article, we cause'it to be completely surrounded with a layer of soapstone, even though sand may be employed about the layer of soapstone. We sometimes use moist sand or pulverized soapstone. When the articles are thus properly placed in the box, we subject the sand or other material to pressure, so that the box shall be solidly filled ; we then by means of a cover, or sometimes by pressure, confine the sand or other material so that the articles shall be at all times in contact with and pressed upon by the sand or other material during the process oi heating. We then place the articles surrounded with and sustained by sand or pulverized soap-stone or other material in an oven or heater, and subject the same to a high degree of artificial heat, moist or dry heat, say from 260 to 300 Fah , for a period oi from three to seven hours, and upon taking the articles out of the sand or other material, the articles will be found to be vulcanized in the same form in which they wers when put into the sand; we are thus enabled to produce economically great variety of objects. Among them, embossed, or indented, or plain sheets or plates or masses oi regular or irregular forms, convex or concave, such as pieces of furniture, book covers, buttons, toy of various kinds, c,or we make the moulds ?? plaster of Paris, (best calcined), or other substance, which, when dried will be porous and permit the escape of gases evolved from the matter under treatment, and all contained air, and thereby prevent the expansion of confined air and other gases Irom injuring the surface of the moulded substance, or we mould the article in a mould which is to produce the figure, and pack in sand, or pulverized soapstone or other like granular pulverized substance to support the other surface or surfaces of the article to be produced, and thus keep the face, which is to be figured, in contact with the partial mould of metal or plaster, or other material, and thus afford a iree discharge for air and gasses, whilst at the same time the moulds are greatly cheap- ' ened. The moulds or outer casing may be ' made of glass instead of iron or other metal, ] but we prefer the first mode of procedure, as it ; avoids entirely the use of moulds during the ( process of vulcanization. The sand or othe pulverized or grandular material, having the effect thoroughly to support and retain the form previously given to the article by moulding or modelling. The prepared caoutchouc, gutta percha, & c, if it is to be imbedded in moistened plaster should be previously varnished, and to keep the surface ot such articles to be thus vulcanized in sand, smooth india paper, should be interposed between such surface and the sand. The claim for this invention may be found on page 254, as above stated.
This article was originally published with the title "Improvement in the Manufacture of India Rubber Goods"