US3676174A - Coating and forming - Google Patents

Abstract

FORMED OBJECTS ARE GIVEN A HARD COAT BY RUBBING A DRY POWDER AND PLASTER OF PARIS THEREON, PAINTING THE SURFACE WITH A MIXTURE OF THIS POWDER AND POLYVINYL ACETATE, AND ALLOWING THE PAINTED SURFACE TO CURE. THE POWDER MAY BE WOOD FLOUR OR MICROPOROUS CELLULOSE. IF DESIRED, A METALLIC COATING MAY BE PROVIDED BY FURTHER PAINTING ON A COATING OF A FINE METAL POWDER SUSPENDED IN POLYVINYL ACETATE. THE MIXTURE ITSELF OF POWDER, PLASTER OF PARIS AND POLYVINYL ACETATE MAY BE SHAPED OR MOULDED INTO THE FORM OF USEFUL OR DECORATIVE OBJECTS.

Description

United States Patent 3,676,174 COATING AND FORMING Herman Spector, 75 Central Park W., New York, N.Y. 10023 No Drawing. Continuation-impart of application Ser. No. 698,707, Jan. 18, 1968, now Patent No. 3,558,340. This application Nov. 16, 1970, Ser. No. 90,161 The portion of the term of the patent subsequent to Jan. 26, 1988, has been disclaimed Int. Cl. B44c 1/06; B4441 1/094 US. Cl. 117-26 7 Claims ABSTRACT OF THE DISCLOSURE RELATED APPLICATION This application is a continuation-in-part of my copending application Ser. No. 698,707 filed Jan. 18, 1968, now Pat. No. 3,558,340, and relying on a British filing date of Jan. 20, 1967.

BACKGROUND OF THE INVENTION This invention relates to a process for hard coating and rendering permanent objects such as art objects, and also to casting and coating compositions.

Modelling clays of the commercial type, known in the market as Plastina, Plasticine, or the like, are composed of a fine clay suspended in oil or wax rather than water to render it more or less permanently pliable. This clay has many advantages in that it does not dry out so that a sculptor or other worker may work at his convenience without his workpiece drying out as is the case with water based clays. However, a piece of sculpture or the like made from oil based clay must be passed through additional time consuming and expensive processes to render it permanent. Usually it has to be cast in a plaster or rubber mold and then recast in some permanent medium. This invention allows a sculpture or other workpiece of oil based clay, to be hard coated and rendered permanent. As used herein, the term oil based clay is intended to include wax and wax and oil based clays.

SUMMARY OF THE INVENTION Wood, plastic, metal, ceramic, paper or clay is coated by the steps of rubbing into the surface a fine powder mixture with plaster of Paris, painting the surface with a mixture of the above powder and polyvinyl acetate, and allowing the painted surface to cure. The cured surface may then be painted conventionally or a metallic coating may be provided by further painting the surface with a mixture of fine metal powder suspended in polyvinyl acetate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Step N0. 1'

An art object or the like is modelled from an oil based clay such as Plasticine. These clays are well known by sculptors, students, hobbyists, and other workers as non-hardening, non-drying pliable materials.

3,676,174 Patented July 11, 1972 Step No. 2

A powder is prepared by mixing a fine wood flour of IRS No. 50 fineness with fine plaster of Paris. The powders should be mixed in a ratio of about equal amounts of volume for best results. The clay object to the coated is completely dusted with the powder mixture which is rubbed into the surface with a resilient object or by the fingers. Any remaining loose powder not rubbed into the clay surface is brushed off with a soft hair brush.

Step No. 2 has been tried using talc, starch, and other fillers for the wood flour and with tile grout, cement, lime, and plastic urea resins in place of the plaster of Paris. These substitutes were used in various combinations, alone and mixed with each other, without satisfactory results. The use of a mixture of wood flour and plaster of Paris gives a hard, dry, tough, non-pliable, non-oily base which gives a clay object the ability to be further coated.

Step No. 3

From 25 to 50 parts by volume of the above mixture and parts by volume of polyvinyl aceate diluted with water to the consistency of milk are mixed together in a small container. The liquid mixture is rapidly applied to the coated clay surface of Step No. 2 and allowed to dry or cure. The liquid is best applied with a soft hair brush although it could also be sprayed. Curing time is usually completed in a few minutes. For particularly fine detail work, two or more thin coats are best applied allowing a few minutes for each coat to cure. When dry, all details, hair lines, creases, and indentions in sculptured objects are brought out and highlighted.

Acrylic, casein, and other water soluble resins were substituted for the polyvinyl acetate solution used in Step No. 3; however, the results were not satisfactory.

At the conclusion of Step No. 3, the clay object has a hard coat and is in permanent form. If desired, it may be further finished by painting with clear or colored urethane finish, lacquer, shellac, varnish, or other hard drying material. In addition, metal powders, such as gold or bronze, may be applied mixed as a suspension in a lacquer or other vehicle. For a less smooth surface, the metal powder may be applied in the liquid mixture of Step No. 3. This provides a more textured surface. Colored over coatings may be painted over the metallized finish and wiped off while still wet to allow desired metallic highlights to appear. When completed, a coated clay object may be waxed for additional protection.

The following additional steps may be followed if it is desired to give the coated object a metal plated appearance.

Step No. 4

Apply a hard clear coating, as described above, of lacquer, shellac, varnish, or the like.

Step No. 5

Mix a dry powder of one part plaster of paris, one part wood flour, and six parts fine metal powder. Mix this dry powder with an equal part by volume of polyvinyl acetate solution diluted with water and rapidly brush the resulting mixture with long steady strokes onto the coated clay object. This mixture hardens rapidly and requires that the brush and the mixing container be washed after each use in water. Several such coats will provide a harder and more dense metallic coating.

Step No. 6

If a bronze coating was applied in Step No. 5, dilute ammonium sulphide may be applied to give a brown or black patina. To get bronze highlights through the patina, the coated clay object may be lightly burnished with fine sandpaper. In a like manner, green to tur- 3 quoise patinas may be provided by applying or brushing on dilute cupric nitrate, dilute ammonium acetate, dilute cupric carbonate, or dilute sodium thiosulphate and ferric nitrate. After burnishing, the metal coated clay object may be waxed and polished with a soft cloth.

When skillfully carried out, an oil based clay sculpture coated according to this invention will give the appearance of a bronze casting and will be a permanent art object.

The ingredients of the above coatings may be diluted in a suitable vehicle, e.g., water, and then cast in molds. After evaporation the hard formed articles can be shaped by machining and if not quite hard by pressure.

The end product from casting the above compositions into art objects for example, is lighter in weight than mere plaster of Paris with water. The product is tougher, harder, less brittle and less subject to chipping, breaking, crumbling, crazing or chalking than corresponding compositions of plaster of Paris with water.

The product cast from the present compositions can be coated easily by a mixture of polyvinyl acetate with powder, plaster of Paris and water. The powder in coating or casting may include metal particles to give a metallic character to the product. The particles are preferably about 40 to 350 mesh and may be bronze, copper, brass or a mixture of metals. Other metals of silver color such as aluminum may also be used.

Objects to be coated may be of wood, metal, concrete, plastic, clay, paper or ceramics. Structural elements such as blocks or the like may be coated for decorative effects. A metal plated appearance can thus be achieved. The coated product may be colored by inclusion or dyes, or colored powders such as metal oxides and may be antiqued. The object may be polished, smoothed or burnished after coating.

Further examples of the invention are as follows:

CASTING MATERIALS AND PLATING MATERIALS The products used for this new, novel casting (molding) material are:

40 to 60% by volume of fine mesh plaster of Paris mixed with 40 to 60% by volume of wood flour (microporous cellulose) 150 mesh or finer. Mix these two powders dry.

Add polyvinyl acetate emulsion, dilute with water (by volume from 25 to 60%).

I have found that a polyvinyl acetate emulsion diluted with water in the ratio of 60% PVA and 40% water or 50% each by volume added to above mixed powders makes a most satisfactory casting material as to setting time, amount of hardness, toughness, and other qualities expressed above in my description of castings.

Water is cheaper than the polyvinyl acetate emulsion, but this emulsion is the binder, additive or catalytic agent that creates a new material.

There is a chemical reaction between the polyvinyl acetate diluted with water and the plaster of Paris, and a reaction of the wood flour and the adhesive qualities of the polyvinyl acetate solution.

The powders and the diluted PVA emulsion are mixed in a container.

The liquid mixture is either (1) Cast in a mold.

(2) Applied to any hard surface or object by brush or air spray.

(3) When casting, the mixture of the powders and the polyvinyl acetate emulsion should be prepared in sutficient quantity for the size or volume needed for the job.

(4) Allow the casting to dry and cure before removing from the mold.

(5) Any imperfections in the surface of the casting, can be easily remedied or repaired with the application of alsmall amount of newly made batch of casting materia (6) Before casting is completely hard or cured, any irregularities or imperfections may be easily trimmed with a knife.

(7) Hardened castings can be sandpapered. It is advisable to do this before complete curing.

Process of plating or coating ceramic objects, clay, wood, plastic, metal, plaster of Paris, or any other object where electroplating is not practical or feasible Objects can be plated or coated with powdered metals such as bronze, brass, copper, aluminum, etc. and/or for direct color effects dry color powders may be added, also silic acid and metal oxides.

(I) BRONZE (NON-FERROUS) PLATING OF OBJECT A bronze metallic electrolytic powder is used for plating. The mesh of the metal powder can be from about 40 mesh to 325 mesh.

The finish desired will determine the number mesh needed. For a most practical smooth bronze plating finish, I have used mesh. For rough texture I have mixed or added heavier mesh bronze powders, and brass key filings may be added. Copper or brass can be added or substituted. These mixtures or combinations of metals and meshes will depend on the desired End Resultant Finish.

l(II) PREPARATION AND APPLICATION OF PLATING MIXTURE (A) Dry mix 1 part of plaster of Paris (line) with 1 part of wood flour (described above).

(B) Add this dry mixed powder to the bronze metal powder in this proportion: 1 part volume mixed powder 4 parts volume bronze metal powder.

(C) Dry mix thoroughly.

.(D) Add P.V.A. emulsion previously diluted with water 50/50 so resultant mixture has the consistency of heavy cream.

(E) Mix thoroughly and apply to object with brush. Apply with steady stroke. This plating material hardens rapidly. The container and brush must be washed in water after each use.

(F) Several coats of this metal powder, gypsum, wood flour and polyvinyl acetate emulsion will provide a very hard, durable and dense metallic coating.

(III) FINISHING AND PATINA OF PLATED OBJECT (A) When object has hardened, dried and is completely cured, object may be sanded with fine sandpaper wherever high lights are desired, or where the sheen of cast polished bronze is wanted.

(B) Patina or antiquing bronze plated object-The non-ferrous metal plated object can now be antiqued or colored, in part or whole, depending on the finish desired.

(1) To turn the non-ferrous plating to black or deep brown finish quickly, apply a small amount of ammonium sulphide by hair brush or Q tip. Dilute with water for lighter color effects, I have found that vapors of concentrated solution of ammonium sulphide, which are heavy will color copper a beautiful burnt orange or red, as you pass over object and touch lightly in spots.

('2) For green antiqued patina, mix acetic acid, or citric acid, or ammonium acetate with malachite (copper carbonate), add a small amount of polyvinyl acetate emulsion. Apply with brush and allow to dry. The chemical reaction for a real antique finish takes a few days. Repeat if darker effects are necessary.

(3) To antique brass, simply cover with a solution of antimony chloride and allow to dry.

(4) For blue green bronze apply a solution of sodium thiosulfate and ferric nitrate.

(5) For intense green, mix acetic acid and copper nitrate 50/50. Apply and allow to dry. Chemical reaction -will be complete in a few days. I have used different amounts of acetic acid and ammonium acetate, copper nitrate and malachite mixed together and applied to object. Unusual antique effects.

(6) When the desired colors or combination of colors have dried and are set, the object should be sanded lightly to bring out the metallic bronze sheen.

(7) Object can be burnished, waxed or polished with soft cloth.

'(C) Finish.-When skillfully carried out, the plating and the application of the chemicals for a patina, the object has a realistic appearance, weight, feel of an expensive casting at a fraction of the cost.

The casting has now become a durable, permanent art object.

What is claimed is:

1. The process of coating a shaped object comprising the steps of:

-(a) preparing a dry powder mixture comprising wood flour and plaster of Paris;

{(13) dusting the object with the dry powder mixture;

-(c) rubbing the dry powder mixture dusted onto the object into its surface;

(d) removing excess powder from the surface of the object;

(e) preparing a liquid mixture of wood flour and plaster of Paris in water with polyvinyl acetate; -(f) painting the surface of the powder coated object with the liquid mixture; and

(g) allowing the painted surface to cure to provide a hardened coating and permanence for the coated object.

2. The process according to claim 1 wherein in steps (a) and (e) wood flour and plaster of Paris are mixed in substantially equal parts by volume.

3. The process according to claim 2 wherein succes- 5 sive coats of the liquid mixture are painted on the surface of the object and allowed to cure between coats.

4. The process according to claim 2 with the additional step of further finishing the coated object by painting it with a conventional hard drying covering.

5. The process according to claim 2 with the additional steps of:

(h) preparing a second liquid mixture of a fine metal, ,wood and gypsum powder in water with polyvinyl acetate;

(i) painting the object with the second liquid mixture;

and

;(j) allowing the painted surface to cure.

6. The process according to claim 5 wherein the fine metal powder is bronze and with the additional steps of:

WILLIAM D. MARTIN, Primary Examiner R. -M. SPEER, Assistant Examiner US. Cl. X.R.