Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-03-08
2001-10-30
Fiorilla, Christopher A. (Department: 1772)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S089110, C264S642000, C264S679000
Reexamination Certificate
active
06309491
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to decorative pottery articles and a method of making them and, in particular to composite pottery articles wherein a selected object is incorporated into a pottery article.
2. Background and Brief Description of the Prior Art
In the field of ceramic art or pottery, there is a continual effort to find new and desirable decorative effects and methods to create such effects. From the standpoint of the consumer, one such desirable and decorative effect may be achieved when an object of particular interest to the consumer is incorporated as a visible three dimensional constituent in the outer surface of the pottery, as opposed to being merely a two dimensional surface decoration . Thus, for example, a tourist visiting a site of volcanic activity, such as Hawaii, might find a decorative pottery article even more attractive as a momento of a trip if the pottery displayed, as a visible constituent, a piece of lava rock from a local volcano. However, the incorporation of an object such as a lava rock as a constituent in a ceramic or pottery article is difficult since the physical properties of lava rock are different from those of the materials used in the manufacture of pottery articles and may be incompatible therewith as well as unsuitable for the conditions of manufacture of the pottery. For example, a lava rock, incorporated in potter's clay may loosen and separate, or cause the pottery article to crack as a result of shrinkage during drying and firing. As a result, the decoration of a pottery articles is generally restricted to creating such decoration in the form of a two dimensional design on the surface of the pottery or encapsulating a three dimensional object within a thick glass surface layer of a composite glass and ceramic article. The latter approach can result in problems of incompatibility of the encapsulated object with the material of the thick glass layer as well as the ceramic.
U.S. Pat. No. 1,158,863 describes a process for applying an ornament or design to a pottery article and subsequently baking the design onto the surface of the pottery.
U.S. Pat. No. 2,357,399 discloses the manufacture of composite glass and ceramic articles wherein a surface element may be encapsulated within a thick glass outer layer.
U.S. Pat. No. 2,246,052 discloses a process of making a mosaic by forming the mosaic design by molding or routing prior to firing and avoiding the necessity of placing individual pieces of the design in place.
It is an object of the present invention to provide pottery or ceramic articles having incorporated into the article a decorative object.
It is a further object to provide a method for incorporating selected objects into a pottery or ceramic article.
It is a still further object to provide a method for producing a decorative pottery article having a selected rock incorporated into the pottery article.
It is as still further object to provide a decorative pottery article having incorporated therein a selected rock.
SUMMARY OF THE INVENTION
The above and other objects are achieved in accordance with the present invention which provides a method for incorporating a selected rock into a decorative pottery article comprising the steps of
A) shaping the pottery article from pottery clay and partially drying the shaped article;
B) forming a first hole in the surface of the pottery article, sized to hold the selected rock;
C) forming a shrinkage cushion in the wall of the pottery article, in the region surrounding the hole of step (B);
D) placing the selected rock within the first hole so that it is held in place by the surrounding clay;
E) drying the pottery article;
F) firing the pottery article.
The decorative pottery article of the invention may take any of the various forms commonly associated with the pottery art. Thus the pottery article may be a vase, amphora, tile, mug, or the like made from fired clay and glazed, if desired.
The method of the invention is designed to inhibit the cracking of the pottery due to shrinkage of the pottery clay during drying and firing while the selected rock remains relatively stable. Air drying may result in about a 12% shrinkage of the pottery clay and firing may result in about a 1-2% shrinkage while the rock undergoes no shrinkage.
The shaping and partial drying of the pottery article, as in step (A), are carried out in a conventional manner. The partial drying in step (A) is preferably carried out at ambient conditions for one or two days. The forming of the first hole, that is, the hole into which the selected rock will be positioned (step B, above) may be carried out by various procedures. The hole may be formed either as a through hole or as a depression hole. In one embodiment, using the selected rock as a guide, a cutting pattern of appropriate size is traced onto the surface of the partially dried pottery article and the pottery wall is then cut, for example with a knife, along the pattern to form a through hole into which the rock may be forced. It is preferred to cut the edge of the clay surrounding the hole to a tapered edge, preferably forming an angle such as, about a 45° with the point of the angle facing the rock position. The narrowing of the clay wall at this point contributes to the inhibition of shrinkage.
In another embodiment, the first hole may be formed as a depression hole rather than as a through hole. This may be accomplished by simply pushing or pressing the rock (or other suitably sized object) into the pottery wall, without cutting, before the pottery is completely dry. The rock, or other object, is then removed leaving a depression hole of sufficient size to accommodate the rock.
In step (C), a shrinkage cushion is formed to compensate for shrinkage and inhibit cracking of the pottery during drying and firing. The shrinkage cushion may be provided in various forms. In one embodiment, where the first hole is a through hole into which the selected rock will be placed, the shrinkage cushion may be provided in the form of a multiplicity of secondary smaller holes, preferably through holes, in the pottery wall in the region surrounding the first hole. In an alternative embodiment, the shrinkage cushion may be provided in the form of a groove in the pottery wall, surrounding the first hole. The groove is preferably cut to a depth extending about 75 to 85%, ideally about 80%, through the clay wall. Grooves of shallower depth are less effective in inhibiting the cracking of the pottery during drying and firing. Deeper grooves may unduly weaken the pottery wall. The holes and/or grooves that are used as shrinkage cushions may be of various cross-sectional shapes, such as round, triangular, rectangular or other. When the first hole (step B) into which the rock will be placed, is a depression hole, a shrinkage cushion may be formed by drying the pottery article, for example, at ambient conditions for about 10 days to two weeks, then partially filling the depression hole with a moist clay/glaze mixture.
The glaze/clay mixture serves as an adhesive to hold the rock in place as well as serving as a shrinkage cushion to inhibit the cracking of the pottery wall during subsequent drying and firing cycles.
When the rock is placed in the wall of the partially dried pottery, it is preferred to first wet the rock by dipping in water prior to placing. When the hole of Step B is a depression hole, it is preferred to coat at least the underside of the rock with clay/glaze mixture before placing it in the hole. The remaining empty space in the depression hole may subsequently be filled with additional clay/glaze mixture.
The article is dried in a conventional fashion at room temperature, typically for about two weeks, after which (step F) the holes and/or groove, are filled with a moist clay/glaze mixture. The clay/glaze mixture has a lower softening point than clay and thus serves as a cushion to inhibit cracking. The composition of the clay/glaze mixture employed is typically between about 40/60 and about 60/40, and is most prefera
Chang Inwoo
Cookfair Arthur S.
Fiorilla Christopher A.
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