Metal etching sometimes replaces casting and engraving, it makes the whole process much easier. You can get a pattern both concave - embossed, and convex - bas-relief. Metal etching at home can be chemical and galvanic. The first option is more toxic when used at home, so we will use the second one first, it is also called electrochemical.
Equipment
You need to take a power supply or a transformer that can output from 4 to 7 V. In addition, you need a dielectric bath, it should contain the necessary part and a second metal object that is connected to the anode.
To carry out the etching of a pattern on a metal, it is necessary to use a solution of ferrous sulfate as an electrolyte. If a drawing is needed on a copper or brass surface, then copper sulfate is used. You can also applyferric chloride. The main thing is that the water is distilled.
Preparing the part for etching
In order for the etching to be uniform and in the right places, the part must be cleaned of dirt and degreased. For more convenient work, copper wire is soldered to the part with tin, it will be convenient to hold the object for it. To clean the surface, you need to lower the object to be converted into 10% sodium hydroxide, the temperature of which is 50 ° C, then into a 15% sulfuric acid solution and hold it there for two minutes, then rinse it in hot water. When the procedure is completed, the surfaces of the object will be completely cleaned, and of course, you can not touch them with your hands.
Electrochemical metal etching
We need to protect places that shouldn't be pickled. To do this, it is necessary to apply a special mastic to these areas of the surface. It is made from three shares of wax and two - rosin, they are melted in a tin, stirring. After everything turns into a homogeneous mass, it is allowed to cool and divided into fragments. Each of them is placed in gauze, so that when pressed, as much mastic as necessary can seep through it. After that, the workpiece, which we will pickle, heats up. Now we take the created mixture, which was placed in gauze, and rub the surface with an even layer.
After cooling, the mastic becomes solid. From above it is covered with light water-soluble paint. It can be watercolor or gouache white. After that, the coating should dry. Then you canapply a drawing, it will hold well on the paint. It can be drawn with a pencil or translated through carbon paper. Then this contour must be scratched with a needle to the very metal.
Now the metal is etched by electrolysis, we connect one rod to the anode - plus, the other to the cathode - minus. To the first we connect the part on which the image will be applied, to the second any steel plate. After that, the process of etching the metal begins where the image was scratched.
If you need to create a multi-level drawing, everything is done in the same way as described above. Only the contours are checked every time, and when the smallest of them are etched to the prescribed depth, the part is removed and painted over with heated mastic using a brush. When it hardens, everything is repeated again until the next level of the drawing. In the process, the image is gradually created.
In this way, metal is etched at home, after which the surface is washed with turpentine, and then polished, giving the product a finished look.
Chemical pickling
Now let's look at how to create a pattern on a metal surface without the use of electrical appliances. To do this, we need chemicals that are freely sold in hardware stores. So, let's begin. For etching we need:
- White Spirit;
- paint that does not dissolve in White Spirit;
- acetone;
- resin used to cover roofs;
- s altcookbook;
- blue vitriol.
Cleaning the part
To begin with, the part where the image is planned is cleaned with fine sandpaper and degreased. When the surface is ready, you need a place where the pattern will be applied, sealed with adhesive tape or something similar. After that, the rest of the surface, where chemical etching should not affect the metal, is painted over with paint. It can be of any color, as long as it is resistant to White Spirit.
When the paint is dry, you can remove the adhesive tape. Beneath it is pure metal, ready to be painted on. Now on this "mini-canvas" you need to apply an image. It is made using resin, which is dissolved in White Spirit until it becomes liquid, like paint. She draws the desired image with a brush. What is good about such improvised paint is that if something does not work out in the drawing, then it will be possible to remove it by moistening a rag or cotton swab in White Spirit. If there are very small details in the drawing that did not turn out well with a brush, they can be corrected with a needle, scraping off the excess after drying.
In this way, you can etch a knife, keys, in general, any metal object. Now that the drawing is completely ready, you can proceed to the etching itself.
Etching solution
We need a liter of water, in which we need to dissolve 100 g of copper sulfate, and then add s alt. It must be poured until it ceases to dissolve. The resulting mixture will have a blue color. However, after a metal object is immersed in it, the color will begin to change to green.
So, we are loading the item. The chemical process starts immediately. In all this production, no substances harmful to he alth are emitted, so this metal etching at home is safe.
Actions in a chemical reaction
During the reaction, a plaque is formed, which will become more and more. It slows down the whole process, so you need to periodically wash it off with water. You should not do this with the help of various brushes, brushes and other tools, because you can damage the paint. But she seems to be holding the whole drawing, and it will be a shame if, by etching a knife, for example, you inadvertently damage the drawing on it. This is a very delicate work that requires a steady hand and patience.
The depth of the pattern directly depends on the time during which the metal will remain in solution. There are no exact criteria, so each master must himself observe the course of a chemical reaction. And only after doing this several times, it will be possible to say with confidence how much time is needed for the desired pattern to develop to the intended depth.
Advantages and disadvantages of electrochemical and chemical etching
The advantages of electrochemical metal etching at home include the fact that the pattern being created is clearer, this can be clearly seen if you look atit when magnified. However, the downside is that this method requires an electrical device, which may not be available to everyone.
The advantages of chemical etching include the fact that everything you need can be bought at a hardware store. These ingredients are cheap, and best of all, you don't need to look for a power supply or other devices capable of delivering from 4 to 7 V. However, the imperfect edges of the pattern are a minus.
