Printed circuit boards are widely used by radio amateurs when creating various mechanisms, as well as for connecting various electronic components. Such boards are made by many radio amateurs at home, on their own. To do this, the special pattern that makes up the printed circuit board is transferred to the so-called sheet textolite. To transfer the pattern, a laser printer is used, which prints the location of the tracks, and an ordinary iron, with which these tracks are transferred from paper to textolite. Then, having transferred the pattern to the textolite, it is necessary to engrave it. There are several recipes, methods of etching printed circuit boards, which are actively used by radio amateurs at home.
The use of ferric chloride
Often when etching printed circuit boards at home, ferric chloride is used. To carry out the etching procedure, it is recommended to use a plastic or glass container in which water has been poured. It should be noted that the water temperature should vary between 50 and 70 degrees Celsius. Otherwise, if the water temperature is higher than these values, then the pattern applied with toner or varnish will gradually melt and then work.
To etch the board in ferric chloride, you must first prepare a special solution. It is necessary to take ferric chloride and in small portions, constantly stirring, add it to the water. It should be noted that when making such a solution, it is recommended to use a respirator, since when ferric chloride gets into the water, a chemical reaction begins, as a result of which harmful vapors for the human health are formed.
As a result, after adding ferric chloride to water, a composition with a brown tint should be obtained. It should be noted that if the resulting mixture has a dark greenish tint, then the chemical reaction process will last much longer.
To etch a printed circuit board, it must be placed in the resulting solution so that the printed conductors are at the bottom. When engraving double-sided panels on the bottom of the container, it is recommended to lower the layer in which there is a maximum and high level of density.
To fix the board in the solution, you can use small pieces of foam or a thread stretched longitudinally over the container. When etching, it is recommended to periodically shake the board, which is in solution. The average etching time in a ferric chloride solution can be 10 minutes to 1 hour.
It should be noted that the etching time in a fresh, freshly prepared solution can be around 3-30 minutes. This is due to the fact that the concentration of the made solution and the water temperature indicators affect the speed of chemical processes.
The use of copper sulfate and table salt
Making a solution of copper sulfate and table salt is quite simple. To do this, take 200 ml of warm, clean water and add 1 tbsp of copper sulfate and 2 tbsp. table salt. Then the resulting mixture must be thoroughly mixed, after which you can proceed to the etching procedure.
It should be noted that etching printed circuit boards by this method is very time-consuming. However, the advantage of such a solution is self-healing. Also, most experienced users, in order to speed up the reaction and the burning process, recommend periodically heating the solution and shaking the board from time to time.
Use of hydrogen peroxide and citric acid
Many hams use tools like citric acid and hydrogen peroxide to bait the boards quickly, especially at room temperature. This method is very popular among users due to the availability of ingredients to create a solution.
To make an etching composition, you need to take 100 milliliters of hydrogen peroxide (3%) and add citric acid (30 grams) to it. Then a small amount of table salt (about 5 grams) should be added to the resulting composition.
It should be noted that it is not recommended to dilute the resulting mixture. This is because the peroxide stimulates the burning process. Therefore, the higher the concentration of peroxide in the composition, the more intense the chemical process itself will be. It should be noted that the solution based on peroxide and citric acid is disposable. Therefore, it is not suitable for frequent reuse or long-term storage.