US 2869265 A
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Jan. 20, 1959 G, KLEIN METHOD OF MAKING UTILITY AND DECORATIVE ARTICLE OF STAINLESS STEEL Filed Feb. 5-, 1957 IN VEN TOR.
United States Patent METHOD 0F MAKING UTILITY AND DEEORA- .TIVE ARTICLE OF STAINLESS STEEL Gunnar Klein, Halden, Norway Application February 5, 1957, Serial No. 638,346
1 Claim. (Cl. 41-26) The present invention-relates to a method of making utility and decorative objects such as saucers, trays etc. of metal which is provided with enamel and the invention especially relates to providing such objects with transparent enamel in such a way that the metal itself is visible through the enamel, giving various combinations of light reflex therethrough.
It is well known that noble metals such as silver and gold can be provided with transparent enamel so that the silver or gold is visible through the enamel, thus giving the surface attractive appearances. Such objects made of noble metals are, however, very expensive and are therefore not commercially available as utility objects.
The applicant found that stainless steel could be used in the same way when the stainless steel surface is polished to a high degree and the stainless steel surface will then have an appearance very much like the surface of a silver object. It is, however, also well known that stainless steel cannot be provided with enamel by means of the conventional methods for enamelling metals. This is due to the fact that stainless steel does not form oxides on the surface which will combine chemically with the enamel during the fusing of the same. The applicant found, however, that these difliculties could be overcome by roughening the surface of the stainless steel object, and by doing this, the enamel will physically adhere sufliciently well to the roughened surface.
The surface of the stainless steel object could be roughened by grinding or sand blasting the same, but the latter method is not satisfactory because the surface which is visible through the transparent enamel will not have a good and attractive appearance. If the method is to be used the surface of the stainless steel object has to be roughened in such a way that the surface which is visible through the transparent enamel should be brilliant and give different light reflexes, so that the surface in combination with coloured transparent enamel would be base for beautiful articles.
The applicant found then that by grinding the stainless steel surface by means of an adhesive he was able to roughen up the complete surface to be enamelled and simultaneously to give the surface different grounded designs.
It is, however, very difficult to grind the surface to be enamelled in this way on an article, such as saucers, trays or the like, because of the different curved surfaces.
It was then found that a very satisfactory result could be obtained if the surface to be enamelled was ground before the article was formed into shape, that means in sheet form or as a blank.
However, when the article was formed, for instance by drawing from the treated blank, it showed that the fused Patented Jan. 20, 1959 2 enamel did not adhere well at the edges, that means at the marginal area of the ground surfaces. The enamel had a tendency to crack and fall off from these marginal areas.
It was then found that this could be prevented if the marginal areas of the ground surfaces were given an aftertreatment after the article was formed. A suitable aftcrtreatment was found to cover all the surfaces of the article except the marginal areas of the ground surface and sandblast this. 1
When such a treated surface is covered with enamel and fused this sandblasted marginal area will appear as a darker border.
When the ground, formed and aftertreated, finished article has been covered with enamel the surfaces to be enamelled are then covered by means of a stencil and superfluous enamel is removed, for instance by means of a brush. The article is then placed in an oven and the enamel is fused in the usual way whereafter the article is allowed to cure and the bare metal is polished to a high degree. The result is a very attractive and beautiful article with a high light reflex and radiance which is seen through the coloured transparent enamel.
The invention will in the following be explained by means of examples shown in the accompanying drawings, wherein Fig. 1 is a blank of stainless steel,
Fig. 2 is the formed article,
Fig. 3 and 4 are sectional fragments of the article.
The blank 1 of stainless steel is by means of grinding given a design 2 which completely covers the surface to be enamelled. The blank 1 is thereafter formed into the shape of the finished article such as shown in Fig. 2. After this treatment the marginal area 3 of the surface 2 must therefore be sandblasted because the design on the surface 2 on this marginal portion has been smoothed out during the forming. A stencil 4 is thereafter brought into a position in the article so that the stencil 4 will cover all of the surface 2 except the marginal portion 3. The marginal portion 3 is thereafter sandblasted and the whole area 2 and 3 is thereafter covered with enamel 5. Superfluous enamel is removed from the edge 6, for instance by means of a brush. After the enamel has been dried the article is placed in an oven and the enamel is fused in a conventional manner. The article is thereafter removed from the enamel, allowed to cool and the bare surfaces of the stainless steel, such as the surface 7, is thereafter polished to a high degree.
Method of making utility and decorative articles of metals, such as saucers, trays etc., comprising grinding the surface of a blank of stainless steel, forming the blank into the desired shape, sandblasting the marginal area of the ground parts of the surface, covering the ground and sandblasted surface with enamel, drying the enamel, brushing away the enamel from the parts of the surface which on the finished article are to be bare metal, fusing the enamel by heating the article in an oven, cooling the article to room temperature and polishing the bare surfaces of the article.
References Cited in the file of this patent UNITED STATES PATENTS