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Publication numberUS779979 A
Publication typeGrant
Publication dateJan 10, 1905
Filing dateFeb 29, 1904
Priority dateFeb 29, 1904
Publication numberUS 779979 A, US 779979A, US-A-779979, US779979 A, US779979A
InventorsJohn Walter
Original AssigneeJohn Walter
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Manufacturing decorative articles from plastic materials.
US 779979 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)


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- tive Articles from Plastic Materials,

Patented. January it), 1905.


m snomer-unme-oeconarive are-notes rnow; mast-lo MATERIALS SPECIFICATION forming part of Letters Patent No. 779,979, dated January 10, 1905.

Application filed Fehruary 29,1904. Serial 1%, 196,904.

To all whom it may concern:

Be it known that l, JOHN WALTER, a citizen of the United States of America, residing at Detroit, in the county of Wayne and State of Michigan, have invented certain new and usefnl improvements in Manufacturing Decoraof which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to the art of producing decorative articles of various kinds from plastic material, and has particular reference to the construction of a flexible mold for casting the material in.

in the plastic arts gelatin is commonly used as the material for the mold for casting any article which has undercut parts, as in the production of reliefs, panels, medallions, artistic decorations of various kinds, pictorial advertising signs, &c'. Gelatin, however, quickly deteriorates, and the artistic value of the casts made from such molds is soon lost after few casts have been made. lit is. also impossible'to reproduce with a gelatin mold the liner lines and details of the original from which the cast is made and the absence of which greatly impairs such productions.

it is the object of my invention to produce a flexible mold which overcomes these drawbacks, and l have succeeded in constructing a mold of rubber which is far superior to the gelatin mold, not only by reason of its greater durability, which makes it more adapted for commercial uses, but mainly on account of the absolute fidelity with which it reproduces even the finest lines and details of the original, and therefore makes the cast of the highest artistic value. ln thus making a flexible mold from rubber in the manner hereinafter described l have obtained entirely new results in that l have made casts which repre sent the very texture of the material from which the original was made. Thus in the case of an article carved in wood the grain of the wood, tool-marks, and all will be so faithfully reproduced by the cast that the most perfect imitation of wood can be produced with-the companying drawings, in

the artistic value of aid of this rubber mold, as will be more fully described in a concurrent application forLet ters Patent.

In describing the process of making my rubber mold reference will be made to the ac- Figure l is a side elevation of the pattern from which the mold is to be made. Figs. Q, 3., 4:, 5, and 6 illustrate the various steps to be taken in the process of constructing the pool from the pattern shown in Fig. 1, as will be explained by special reference to each figure hereinafter. Fig. 7 is a section of the corn pleted mold together with the supportingmatrix.

in the drawings, A represents the article from which the mold is desired to be made.

if this is. as in the usual practice, a wood carving, the surface of the article is first treated in any known manner to prevent the materials to be brought into contact with it from sticking thereto. Washing it with gasolene in which a little powdered French chalk is incorporated accomplishes the purpose, the surplus French chalk being dusted off after the gasolene has evaporated. The article is then fastened upon a mold-board, as shown in Fig. 2. and covered over with soft clay applied in an even thin layer B as far as it is possible and yet cover all the undercut portions sufficiently to eliminate them from the new surface thus formed. The layer thus applied may have 'an average thickness from one-eighth to one-fourth of an inch. if then proceed after the clay is laid on to make a plaster mold of it. This may be done vby simply covering the article, without taking it off the mold-board, with plastic material of proper consistency to maintain its form with-' out the use of an outside casing, although a suitable casing may be used. For convenience in handling this mold C, as shown in Fig. 3,. is suitably shaped into the form of ablock, and when hardened it is separated from the article embedded therein and theclay removed.

The next step isto' form a duplicate of this plaster mold C of some metal, preferably one that is easy to cast, such as lead or alloys of lead. This metal mold may be made in the after hardening,


usual Way of casting in sand, the plaster mold f Another Way C being used as the pattern. which I have illustrated in the drawings in Figs. 4 and 5 consists in placing theplaster mold C upon a suitable mold-board face side 'up and covering it over with plastic material, counterpart mold D, which, is removed from the mold (J and then used as the mold for casting the lead in, as shownin Fig. 5, in which E represents the resulting lead mold, which of the plaster mold C. After having thus obtained the lead mold E, I can proceed to make the rubber mold. To this end the mold E must be heated to a suitable degree of heat to render unvulcanized rubber plastic when in contact therewith; but since rubber in this condition would stick to the metal the mold must be protected upon its face by some suit able coating. This may be done in various known Ways. A very efficient way is to line it with paper by first applying a coat of paste to the face of the mold and then pressing a double sheet of paper which has been made soft by soaking in water into close contact with every part; of the surface of the mold. A lining of two coats of paper is thus formed, the outer one of which adheres to the surface of the mold, while the inner one has little or no adhesion after the water has evaporated. The mold E being thus prepared, a sheet of thus making a unvulcanized rubber is then laid over it and pressed into close contact with it by using the article A as a pressure-head and heat is applied to the mold. Care must be taken to heat the mold E uniformly to a degree of heat suitable to just render the rubber plastic. If necessary, a sand-bath may be resorted to for the.

purpose; but ordinarily with small articles the the heat of a flame may be used, since the'paper lining greatly helps to diffuse the heat through the whole mass and prevent overheating at any particular spot. Pressure maybe applied by means of screws F or otherwise, and it is obvious that with sufficient pressure the softened rubber will flow and fill out the smallest spaces, even the very pores of the wood from which the article A is carved. In thus pressing, the article A forms the upper die and the mold E the lower die, as shown in Fig. 6, and they must properly register with each other. To obtain this registration mechanicy, some pins or projections a are provided upon the mold-board, as shown in Fig. 2,

v which results in forming the mold E with registering sockets to receive these projections. After the rubber mold is thus formed and the parts have cooled down the article, with the 1 rubber mold adhering-to 1t, can be taken right rubber adheres of paper. water the rubber mold can then out of the mold E, since the pnly to the loose inner lining soakingin cold is a duplicate be readily stripped oil the part A without destroying or marring its minutest details, and after the paper is soaked off and removed the rubber mold is placed back either into the mold E or into the plaster mold 0, making thus a compositeymold. In making plaster castings the inner or rubber portion of the mold is first soaked in water and then placed back into the outer-mold, which it then completely fits, since the slight swelling of the rubber by soaking compensates for the paper which has been removed. .material has hardened the inner or rubber mold is taken from the outer mold and the finished articles detached by carefully peeling off the rubber mold from it. A rubber mold of this character is an entirely new thing in the plastic art, being not only a mold of flexible material in the sense that gelatin is, but being flexible as a whole, which the gelatin mold is not, since gelatin must be associated with a flask or casing of some kind. It will thus be readily understood that my ininvention brings within the scope of the plastic art the commercial production of high reliefs and other work which produced heretofore I in a one-piece mold. Besides, the work produced will perfect copy of the original without restriction to the number of articles that may be produced from the same mold.

The method herein described of making the rubber mold could be departed from in many of its details without departing from the scope of the invention, which includes the ultimate production of a rubber mold which has the character of a mere mask or skin, so-

that it is capable of being removed fromthe cast articles much like a well-fitting glove from the hand without injury or damage to either.

Having thus fully described my invention, what I claim is 1. The herein-described method of forming a rubber mold for use in casting articles from plastic material which consists in first masking the face of the pattern with a layer of clay, then making from the masked pattern a mold of suitable material, then lining said mold with a material adapted to form a parting, then placing a sheet of unvulcanized rubber between the mold and the face of the pattern, pressing the same together and simultaneously applying heat to render the nubber plastic; then removing the molded rubber and pattern together from the mold, and finally stripping ofl the molded rubber fromthe pattern.

2. The herein-described method of forming a rubber mold for use in ca sting articles from I plastic ing t e face of the pattern in a manner to retain the with a layer of general outline After the plastic material, which cohsists' in first maskand applying heat to the without the details and undercut portions,

then constructing a metal mold of the masked pattern, then lining the same with paper, then pressing a sheet of unvulcanized rubber between the rnold and the face of the pattern mold, then cooling the parts, then removing the molded rubber and pattern together from the mold, then stripping the" "i-nolded rubber from the pattern. 10

In testimony whereof I afiix my signature in presence of two witnesses. JOHN WALTER. Witnesses;


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2476994 *Feb 2, 1948Jul 26, 1949Jr Clare L MiltonProcess for making molds
US2611170 *Nov 13, 1946Sep 23, 1952Irene H TheisMold for forming plaques
US2682084 *May 3, 1950Jun 29, 1954Anchors George RMethod of duplicating false teeth
US2712160 *Feb 21, 1951Jul 5, 1955 Method of making individual bowling
US2887746 *Mar 12, 1957May 26, 1959Bogoff HenryMaking of cuff links and the like
US2947046 *Jul 1, 1957Aug 2, 1960Lunkenheimer CoMethod of making plastic laminated core boxes and patterns
US3010166 *Aug 4, 1958Nov 28, 1961Skoning John H SMold for casting operations
US5250250 *Sep 19, 1991Oct 5, 1993Dennis GorskiProcess for forming artificial rocks
US5395577 *May 27, 1993Mar 7, 1995Gorski; DennisProcess for forming artificial rocks
US5683646 *May 10, 1995Nov 4, 1997Mcdonnell Douglas CorporationFabrication of large hollow composite structure with precisely defined outer surface
US6458305 *May 21, 2001Oct 1, 2002Chu Hsiao YunMethod for producing colored sculpturesque polyresin model and product produced thereby
US7931248Dec 28, 2005Apr 26, 2011Boral Stone Products LlcFlat mold for corner-shaped simulated stone products
WO1996035567A1 *May 10, 1996Nov 14, 1996Mcdonnell Douglas TechnologiesFabrication of large hollow composite structure
Cooperative ClassificationB29C33/3857, Y10S425/044