conditions using hydrogen peroxide. Everything is very simple and does not require much effort.
For work, we need the following list of tools:
- Program - layout 6.0.exe (other modification is possible)
- Photoresist negative (this is a special film)
- Laser printer
- Transparent film for printing
- PCB marker (if not, you can use nitro varnish or nail polish)
- Foil textolite
- UV lamp (if there is no lamp, we are waiting for sunny weather and using the sun's rays, I have done this many times, everything works out)
- Two pieces of plexiglass (you can use one, but I made two for myself) you can also use a CD box
- Stationery knife
- Hydrogen peroxide 100 ml
- Lemon acid
- soda
- Salt
- Smooth hands (required)
In the layout program, we make the layout of the board
We carefully check it so as not to confuse anything and put it on print
Be sure to put all the checkmarks on the left as in the photo. The photo shows that we have a drawing in a negative image, since we have a negative photoresist, those areas that UV rays hit will be paths, and the rest will be washed off, but more on that later.
Next, we take a transparent film for printing on a laser printer (available for sale), one of its sides is slightly matte and the other is glossy, so we put the film so that the pattern is on the matte side.
We take textolite and cut it to the size of the required board
Cut the photoresist to size (when working with photoresist, avoid direct sunlight, as they will ruin the photoresist)
We clean the textolite with an eraser and wipe it so that there is no debris left
Next, tear off the protective transparent film on the photoresist
And carefully glue it to the textolite, it is important that there are no bubbles. We iron well so that everything sticks well
Next, we need two pieces of plexiglass and two clothespins, you can use a CD box
We put our printed template on the board, it is necessary to put the template with the printed side on the textolite and clamp it between the two halves of the plexiglass so that everything fits snugly
After we need a UV lamp (or a simple sun on a sunny day)
We screw the light bulb into any lamp and set it above our board at a height of about 10-20 cm. And turn it on, the exposure time from such a lamp as in the photo at a height of 15 cm is 2.5 minutes. I do not advise longer, you can ruin the photoresist
After 2 minutes, turn off the lamp and see what happens. Paths must be clearly visible
If everything looks good, proceed to the next step.
We take the listed ingredients
- Peroxide
- Lemon acid
- Salt
- soda
Now we need to remove the non-exposed photoresist from the board, it must be removed in a solution of soda ash. If it doesn't exist, then you need to make it. Boil water in a kettle and pour into a container
Pour in plain baking soda. You don’t need much for 100-200 ml 1-2 tablespoons of soda and mix well, the reaction should begin
Let the solution cool down to 20-35 degrees (you can’t put the board in the hot solution right away, the entire photoresist will come off)
We take our board and remove the second protective film MANDATORY
And we put the board in the COOLED solution for 1-1.5 minutes
Periodically we take out the board and rinse it under running water, gently cleaning it with a finger or a soft kitchen sponge. When all the excess is washed away, such a fee should remain
The photo shows that it was washed off a little more than necessary, probably overexposed in the solution (which is not recommended)
But it's okay. just take a marker for printed circuit boards or nail polish and cover up all the missteps with it
Next, pour 100 ml of Peroxide into another container, 3-4 tablespoons of citric acid and 2 tablespoons of salt.
Conditions on a specific example. For example, you need to make two boards. One is an adapter from one type of housing to another. The second is the replacement of a large microcircuit with a BGA package with two smaller ones, with TO-252 packages, with three resistors. Board sizes: 10x10 and 15x15 mm. There are 2 options for manufacturing printed circuit boards in: using a photoresist and using the "laser iron" method. Let's use the "laser iron" method.
PCB manufacturing process at home
1. We are preparing a PCB project. I use the DipTrace program: convenient, fast, high quality. Developed by our compatriots. Very convenient and pleasant user interface, in contrast to the generally recognized PCAD. There is a conversion to PCAD PCB format. Although many domestic firms have already begun to accept in the DipTrace format.
DipTrace has the ability to see your future creation in volume, which is very convenient and visual. This is what I should get (the boards are shown at different scales):
2. First, we mark the textolite, cut out the blank for printed circuit boards.
3. We output our project in a mirror image in the highest possible quality, without skimping on toner. Through long experiments, paper was chosen for this - thick matte photo paper for printers.
4. Do not forget to clean and degrease the board blank. If there is no degreaser, you can walk on copper fiberglass with an eraser. Next, using an ordinary iron, we “weld” the toner from the paper to the future printed circuit board. I hold for 3-4 minutes under slight pressure, until the paper turns slightly yellow. I set the heat to max. I put another sheet of paper on top for more even heating, otherwise the image may "float". An important point here is the uniformity of heating and pressure.
5. After that, after letting the board cool down a bit, put the blank with the paper stuck to it in water, preferably hot. Photo paper gets wet quickly, and after a minute or two, you can carefully remove the top layer.
In places where there is a large accumulation of our future conductive tracks, the paper sticks to the board especially strongly. We haven't touched it yet.
6. Let the board get wet for a couple more minutes. Carefully remove the rest of the paper with an eraser or rubbing with your finger.
7. We take out the workpiece. We dry. If somewhere the tracks turned out to be not very clear, you can make them brighter with a thin CD marker. Although it is better to ensure that all tracks come out equally clear and bright. It depends on 1) the uniformity and sufficiency of heating the workpiece with an iron, 2) accuracy when removing paper, 3) the quality of the textolite surface, and 4) successful selection of paper. With the last point, you can experiment to find the most suitable option.
8. We put the resulting blank with future conductor tracks printed on it in a solution of ferric chloride. We poison 1.5 or 2 hours. While we are waiting, we will cover our "bath" with a lid: the fumes are quite caustic and toxic.
9. We take out the finished boards from the solution, rinse, dry. Toner from a laser printer is wonderfully washed off the board with acetone. As you can see, even the thinnest conductors with a width of 0.2 mm came out quite well. There is very little left.
10. Ludim printed circuit boards made using the "laser iron" method. Wash off the remaining flux with gasoline or alcohol.
11. It remains only to cut out our boards and mount the radio elements!
conclusions
With some skill, the "laser iron" method is suitable for making simple printed circuit boards at home. Short conductors from 0.2 mm and wider are quite clearly obtained. Thicker conductors work just fine. The time for preparation, experiments with the selection of the type of paper and temperature of the iron, etching and tinning takes about 3-5 hours. But this is much faster than if you order boards from a company. Cash costs are also minimal. In general, for simple budget amateur radio projects, the method is recommended for use.
In the article we will talk about the methods of manufacturing a printed circuit board and etching the board.
There are many ways to make a printed circuit board. The main method that I personally use is the manufacture of a board from foil textolite (getinaks), by applying a drawing with a drawing pen and etching in a chemical solution. It so happened that I started drawing circuit boards from the sixth grade of the school (today - from the fifth), when computers were the size of entire rooms. At that time, I "pulled". Therefore, I draw a board on a sheet of paper in a cage faster than on a computer, using special programs. True, the most voluminous board in terms of element base that I have ever drawn by hand was a board consisting of fourteen microcircuits and a couple of hundred simple elements.
The manufacture of the board, by applying a drawing with a drawing pen or, more often recently, LUT (laser-ironing technology) and etching in a chemical solution, consists of the following steps, the difference from other methods may differ slightly in the operations themselves and in their sequence:
1. Layout of the placement of radio elements on the board and routing of conductors (tracks). Currently, there are many programs for the development of radio boards. It's easier to just use them. It is possible to engage in development without the use of special programs, but this requires some perseverance and many times more time. In this case, for convenience, the board is drawn on a sheet of paper in a cage, and for redevelopment it is drawn again;
2. A board of the required dimensions is cut out of foil textolite, or getinaks. A more convenient material is textolite, which is essentially a multilayer fiberglass, and the foil keeps better on it than on getinaks. Getinax is a sheet material made of pressed paper impregnated with bakelite varnish. Getinaks is a lower quality material than textolite, and has several properties that I personally do not like:
- can flake;
- printed conductors bounce off overheating faster than textolite, which makes it difficult to replace radio components without damaging the board in the event of their failure;
- there are cases of overheating of radio components, from which the radio board can “smoke”. The same happens when moisture enters high-voltage circuits. Burnt getinax often turns into a conductor (something like graphite). The same happens with getinax if moisture accidentally enters high-voltage circuits. The latter can bring you a lot of trouble;
But with all this, it is decently cheaper and cut with scissors. This is useful when you need to make a quick one-sided board on SMD parts.
3. The ends of the board are processed from sharp corners and burrs with a file or sandpaper;
4. The cut board is wrapped in a sheet with a drawn board. With a thin core, with light blows of a hammer, pits (marking) of future holes are made in those places that were previously marked on the sheet;
5. In the marked places, holes are drilled for future radio components. For small parts - resistors, capacitors, thin-terminal transistors, a 0.5 mm drill is used, for thicker leads, a 0.7 mm drill is used. Other sizes can be used if needed. As a drill, it is more convenient to use a portable drilling machine, which can be purchased at a specialized radio store. You can also use a hand-held electric drill with some skill;
6. After drilling the holes, the board is processed with sandpaper. All burrs resulting from drilling are cleaned off, and the foil is cleaned for further drawing tracks and etching;
7. A drawing pen is made from an ordinary empty rod from a ballpoint pen. To do this, the rod is heated over the flame of a match (or lighter), and when the plastic melts, the rod is pulled out. After the plastic hardens, the end of the drawing pen is cut off to obtain a hole with a diameter of approximately 0.2 ... 0.4 mm;
8. Lacquer (more conveniently - nail polish) 2 ... 5 cm in height is typed into the drawing pen, after which a printed circuit board is drawn: soldering pads are made around the holes, and printed circuit paths are drawn between these pads. With some skill and using rulers as guides, the quality of the picture may not be inferior to factory radio boards;
9. After the varnish dries, the parts of the board not covered with varnish are etched by placing the board in a solution of ferric chloride. At the same time, the copper tracks protected by varnish are not etched, and the copper coating of the board that is not covered with varnish, entering into a chemical reaction, dissolves in ferric chloride. To speed up the etching process, the solution with the board can be heated in a water bath, or simply placed on a central heating battery;
10. After etching, the board is washed with water and using a cotton swab moistened with acetone or another solvent, the varnish is removed from the board, after which it is washed again under running water;
11. Soldering radio components is best done using low-melting solder and flux - rosin dissolved in alcohol.
Should be added:
As a drawing pen, you can use a disposable syringe, while breaking the oblique cut of the needle, grind it so that there are no sharp scratching surfaces of the tip. Recently, there are many markers on sale, the dye of which is not washed off with water and gives a sufficiently strong protective layer, so they can also be used as a drawing pen.
Some masters, after etching the board, are also tinkering. Tinning is done in one of two ways:
1. Soldering iron;
2. The iron bath is filled with Rose or Wood alloy. The alloy, in order to avoid solder oxidation, is completely covered with a layer of glycerin on top. For tinning, the board is immersed in the melt for no more than five seconds. The bath is heated with an electric stove.
Recently, the printer method of transferring a radio card pattern has become more and more widespread.
It consists in the following:
1. With the help of special programs, a radio board is designed and drawn;
2. The image of the board in mirror image is printed on a laser printer on a substrate. In this case, thin coated paper (covers from various magazines), fax paper, or film for laser printers is used as a substrate.
3. A substrate is applied to the prepared board with the front side (picture) and, with the help of a very hot iron, is “lapped” to the board. To evenly distribute the pressure of the iron on the substrate, it is recommended to lay several layers of thick paper between them. The toner melts and sticks to the board.
4. After cooling, two options for removing the substrate are possible: either the substrate is simply removed after transferring the toner to the board (in the case of film for laser printers), or it is pre-soaked in water and then gradually separated (coated paper). At the same time, the toner remains on the board. After removing the substrate, in those places where the toner still separated, you can retouch the board manually.
5. The board is etched in a chemical solution. During etching, the toner does not dissolve in ferric chloride.
This method allows you to get a very beautiful printed circuit, but you need to get used to it, because it may not work out the first time. The fact is that a certain high-temperature regime is necessary. There is only one criterion here: the toner must have time to melt enough to stick to the surface of the board, and at the same time it must not have time to reach a semi-liquid state so that the edges of the tracks do not flatten out. Removing the paper sheet requires some softening with water, otherwise the paper sheet may come off with the toner. Drilling of holes in the printed circuit board is carried out after etching.
PCB etching
There are many compositions for chemically etching copper from a printed circuit board. All of them differ in the speed of the reaction and the availability of chemical reagents necessary for the preparation of the solution. Do not forget that any chemistry is harmful to health, so do not forget about precautions. Here are the chemical solutions for etching printed circuit boards that I personally used:
1. Nitric acid (HNO 3)- the most dangerous and not popular reagent. Transparent, has a pungent odor, is highly hygroscopic, and evaporates just as strongly. Therefore, it is not recommended for storage at home. For etching, it is not used in its pure form, but in a solution with water in a ratio of 1/3 (one part acid to three parts water). Do not forget that water does not pour into acid, but vice versa - acid into water. The etching process takes no more than five minutes, with active gas evolution. "Nitrogen" dissolves the varnish, so before using it, you need to let the varnish dry well. Then, during etching, it will not have time to soften and fall behind the copper coating. Precautions must be strictly followed.
2. A solution of sulfuric acid (H 2 SO 4) and hydrogen peroxide (H 2 O 2). To prepare this solution, it is necessary to throw four tablets of hydrogen peroxide into a glass of ordinary battery electrolyte (a solution of sulfuric acid in water) (the pharmacy name is Hydroperit). The finished solution should be stored in a dark container that is not hermetically sealed, since gas is released during the decomposition of hydrogen peroxide. The PCB etch time is on the order of one hour for a well stirred fresh solution at room temperature. This solution after etching can be restored by adding hydrogen peroxide H 2 O 2 . The assessment of the required amount of hydrogen peroxide is carried out visually: the copper board immersed in the solution should be repainted from red to dark brown. The formation of bubbles in the solution indicates an excess of hydrogen peroxide, which slows down the etching reaction. Precautions must be strictly followed.
Attention: When using the two previously mentioned solutions, all precautions must be taken when working with caustic chemicals. All work must be done only in the fresh air or under a hood. If the solution comes into contact with the skin, it must be washed immediately with plenty of water.
3. Ferric chloride (FeCl 3)- the most popular reagent for etching printed circuit boards. Dissolve 150 g of ferric chloride powder in 200 ml of warm water. The etching process in this solution can take from 15 to 60 minutes. The time depends on the freshness of the solution and the temperature. After etching, the board must be washed with plenty of water, preferably with soap (to neutralize acid residues). The disadvantages of this solution include the formation of waste during the reaction, which settle on the board and prevent the normal course of the etching process, as well as a relatively low reaction rate.
4. A solution of sodium chloride (NaCl) and copper sulfate (CuSO 4) in water. In 500 ml of hot water (about 80 ° C), four tablespoons of table salt and two tablespoons of copper sulphate crushed into powder are dissolved. The solution is ready for use immediately after cooling (when using heat-resistant paint, cooling is not necessary). The etching time is about 8 hours. To speed up the etching process, the solution with the board can be heated up to 50 °C.
5. A solution of citric acid in hydrogen peroxide (H 2 O 2). In a small bath (up to 100 ml), a printed circuit board is poured with a large volume of hydrogen peroxide, after which 1 tablespoon of citric acid is added there. After that, the process of etching the printed circuit board begins. It is actively accompanied by a change in the color of the liquid from transparent to blue. The edges turn out to be even and, if you first walk along the foil-coated fiberglass with fine emery, then everything will be etched very evenly.
Using this method, I managed to get boards with the following parameters:
The gap between the conductors is 0.2 mm.
With a set conductor thickness of 0.25 mm, in fact, it turned out to be 0.2-0.22 mm.
Board dimensions up to 100x200 mm.
If you need to pickle faster, you can add a pinch of regular table salt. It will speed up the process, but be careful: During the pickling process, thermal energy is released and usually the solution warms up quite a bit. For my long-term practice of working with this solution, it exploded 2 times and “smeared” everything around. Of course, everything was very quickly wiped off with an ordinary rag with soda and there were no marks on clothes or things from it (unlike ferric chloride, it does not remain), but it is quite interesting to observe this.
The average pickling time is 20-30 minutes.
I did not use other solutions for etching printed circuit boards. It is most pleasant to work with the last item, since the components can be obtained in any city.
If you need quality
In principle, a printed circuit board can also be ordered at a plant specialized for their production. Of course, it costs more than you would make it yourself, but the workmanship will be many times better. If you have a lot of such prototypes, then I highly recommend watching a video on the production of printed circuit board assembly right away.
The point here is the following. The factory takes money for 2 things: for pre-production, during which it translates your PCB files to its standard and manufactures tooling, and for the fabrication itself. The production itself is not an expensive thing: factories buy blanks for radio boards in large volumes and the production itself is cheaper from them, but they charge an average of 2-3 thousand rubles for preparation. For me, paying that kind of money for the manufacture of one board does not make sense. But, if there are 10-20 of these boards, then this money for preparation is divided between all the boards and it turns out cheaper.
High-quality installation is the key to reliable and long-term operation of a device. In this article I will try to briefly and in detail explain the whole process of creating printed circuit boards. The LUT method is the most accessible of all existing ones, many have probably heard the name, and many are familiar with it, since more than half of people who are passionate about electronics use this particular technology to create printed circuit boards at home.
All you need to create fairly high-quality printed circuit boards at home is a laser printer, an iron - preferably domestic and, of course, a piece of foil fiberglass. A template with exact dimensions must be printed on a laser printer (namely, a laser printer), be sure to have the darkest possible shade, then carefully cut out the template.
At the same time, many advise printing the template on photo paper, but I personally have never used photo paper (and I don’t have a laser printer, I have to run to the nearest Internet club every time), in my case, plain A4 paper.
After this operation, you need to prepare the board, and for this, the first step is to cut the fiberglass to the size of your board, then carefully clean the surface of the foil with a fine sandpaper to a shine, then rinse the foil with a solvent or acetone. After that, we immediately begin the process.
Let's heat up our iron. Initially, I advised using domestic ones, the reason is quite simple - the bottom of branded irons is not smooth, and their weight is not very good, but domestic is what you need. We lay the template evenly on the board so that the toner looks at the side of the foil, then carefully begin to iron the board. Those who are doing the process for the first time, I advise you to fix the template relative to the board, so that in the end a curved board does not come out.
You need to iron for 90 seconds (I personally do this), after which we cut down the iron and let the board cool for one or two minutes, then we bring a vessel with water and throw the board there for a few minutes, after which we carefully remove paper.
The result is an almost finished semi-finished product, in places where the toner did not stick well or is completely absent - you can cover it with ordinary nail polish or manicure. To do this, take a varnish, a toothpick and finish the board. Let the manicure or varnish exhale for 15-30 minutes (depending on the specific varnish). Next, you need to prepare for the last stage - etching, and we'll talk about this further ...
After the template
applied to the surface of the foil fiberglass, it's time to start the process of etching the board - this stage is the easiest. Someone uses copper sulfate for etching, others ferric chloride, in my area this is all a luxury, so I have to use an alternative method of etching printed circuit boards.
First, a little about the ingredients. All we need is a teaspoon of table salt, citric acid (2 bags of 40g), and hydrogen peroxide - 3% solution.
Where to get all this? Table salt can be stolen from your own kitchen, hydrogen peroxide is sold in 100mg bottles at any pharmacy (we need 2 bottles), and citric acid can be purchased at any grocery store.
Next, you need to look for a suitable vessel - plastic, glass or enameled. In this vessel, we mix all our components and add 20-50 ml of ordinary tap water to the solution. At the end, it remains to throw our board into the solution.
After 40-60 minutes, the board will be etched. The disadvantage of this solution is that it is enough for 2-3 boards the size of a pack of cigarettes, in fact, almost a one-time solution, but accessible to everyone.
All that remains next - you yourself know better than me - drilling holes for components, tinning the tracks (if you wish, but I advise you, the tin layer saves the copper tracks from oxidation) and the final assembly of electronic components.
The LUT method allows you to get fairly high-quality tracks with a thickness of up to 0.3-0.5 mm, therefore, it can be used to create printed circuit boards of almost industrial quality, but if you make a board, say for surface mounting (in the case of assembling digital devices of one kind or another ), where processors and integrated circuits with numerous small pins are involved, then the LUT method is not the best option, then a more modern and high-quality method for creating printed circuit boards, photoresist, comes to the rescue.
Hello dear friends! At 5:30 in the morning, I specifically woke up early today to write something useful. And yes, today is May 9 on the calendar, so I congratulate you on this great day, Victory Day!
And Today we will talk about a solution for etching printed circuit boards, which is striking in its availability and simplicity. Yes, today we’ll talk about how you can pickle a board with hydrogen peroxide and citric acid, and a little bit of salt.
What pickling solutions exist
For etching printed circuit boards, there are many different solutions, among which there are popular etching mixtures and there are not very popular ones.
In my opinion, the most popular pickling solution in the amateur radio environment is ferric chloride. Why this is so, I do not know, maybe it's a conspiracy of radio shop sellers who specifically offer ferric chloride and tactfully keep silent about alternatives. And there are alternatives:
- Etching with copper sulphate and salt
- Etching with ammonium persulfate
- Etching with sodium persulfate
- Etching with hydrogen peroxide and hydrochloric acid
- Etching with hydrogen peroxide and citric acid
If you have more options for etching solutions, I would be grateful if you share them in the comments on this post.
What are the disadvantages of etching in ferric chloride
A solution of ferric chloride is good for everyone, it is not difficult to prepare and the etching process usually goes quickly. When cooking, it is very easy to deal with the concentration, which is called “by eye”. Once prepared solution is enough for dozens of boards. But it has some disadvantages that are very disturbing:
- The solution is not transparent, which makes it difficult to control the process. You have to constantly remove the board from the pickling solution.
- A solution of ferric chloride is very dirty plumbing. Each board etching session ends with the process of shuffling plumbing (sinks, bathtubs and everything that the solution can come into contact with).
- It stains clothes very badly. When working with ferric chloride, you should wear clothes that you will not be sorry to throw away, because the solution is very strongly eaten into the fabric, so much that it is almost impossible to wash it off later.
- The solution aggressively affects any metal in the vicinity, even if stored in a leaky container, nearby metal objects may become rusty. Somehow I closed a jar of ferric chloride with a metal lid (the lid was painted), after a couple of months this lid turned into dust.
How to Etch Boards in Hydrogen Peroxide and Citric Acid
Although I have always been a supporter of the conservative path, despite all the advantages of the FeCl3 solution, its disadvantages are gradually pushing me to search for alternative pickling mixtures. And so I decided to test the method of etching circuit boards in hydrogen peroxide and citric acid. 
On the way home, I went to the grocery store and, in addition to products for a delicious dinner, grabbed 4 sachets of citric acid, 10g each. each. Each bag cost me less than 6r.
I went to the pharmacy and bought a bottle of hydrogen peroxide, it cost me 10 rubles.
I don’t have any project at the moment, so I decided to test the method purely, to understand what the whole point is. I found a piece of foil textolite in my stash and made a few strokes with a permanent marker. This is a kind of imitation of tracks and copper polygons, for experimental work it will do just fine. 
The solution is not difficult to prepare, but it is important to observe the proportions. Therefore, pour 100 ml of peroxide into a plastic tray and pour 30 g of citric acid. Since I had 10 g bags, I poured out 3 bags. It remains to salt the whole thing, put 5 g of table salt, this is about 1 teaspoon without a slide.
I noticed that even more salt can be added than is required, this leads to an acceleration of the process. Mix thoroughly. It is very important that you do not need to add water to the solution, so for preparation we choose such a container so that the solution covers the board, or we increase the amount of the solution, observing the proportions. 
We put our "printed circuit board" in the resulting solution and observe the process. I want to note that the solution turned out to be completely transparent.
During the etching process, bubbles begin to form and the temperature of the solution increases slightly. Gradually, the solution begins to turn greenish - a sure sign that the etching is in full swing. In general, the whole etching process took me less than 15 minutes, which I was very pleased with. 
But when I decided to pickle another board in the same solution, a little larger than this one, then everything turned out to be not so positive. The board was etched exactly by half and the process slowed down very much, slowed down so much that it was necessary to complete the process in ferric chloride.
Apparently the power of the solution is enough for the time while the chemical reaction between hydrogen peroxide and citric acid is going on. The process can be extended by adding and adding the required components.
Benefits of etching in hydrogen peroxide and citric acid
From the experience gained, we can conclude that this method, like others, has its pros and cons, it has both its advantages and disadvantages.
Main advantages:
- Ease of Access - All components are readily available at your nearest pharmacy and grocery store.
- Relative cheapness - all components for preparing the solution are not expensive, less than 100 rubles. (at the time of writing)
- Clear Solution - The resulting solution is clear, making it easier to observe and control the etching process.
- Etching occurs quite quickly and does not require heating
- Doesn't stain plumbing
What are the cons
Unfortunately, in addition to all the advantages, this etching method is not without its drawbacks.
Cons of etching in hydrogen peroxide and citric acid:
- Disposable solution - the solution is suitable for single use only, i.e. during a chemical reaction taking place in it. It will not be possible to pickle a lot of boards in it, for each time you will have to prepare the solution again.
- Expensive - despite the fact that all the ingredients are cheap, in the long run the solution is more expensive than the same chlorine gel. After all, for each new board, the solution will have to be prepared anew.
That's basically all the shortcomings. In my opinion, this method of board etching has the right to life and it will definitely find its supporters and admirers. And in some cases, this method may be the only possible alternative, for example, in a remote village with a pharmacy and a grocery store.
And on this I will round off. It's already dawn outside the window and it's time to cook a delicious breakfast.
I once again congratulate you on Victory Day and wish you good luck, success and a peaceful sky over your head!
N/A Vladimir Vasiliev