The topic of making circuit boards is not new, much less drawing with a marker or varnish, but in my city there are few places where you can buy a marker. And in almost all stores they are the same - I ran through all the stores and still haven’t found anything new, there are only 2 types of markers, well, they’re also multi-colored, but they definitely don’t suit us. Today we will test this set of markers for drawing printed circuit boards: 2 pens and nail polish (it’s certainly unbeatable).

For the experiment, I took a piece of PCB, sanded it and began to draw something. It turned out something like this, I’ll say right away that our test is brutal and not adequate, but it will already make it clear what’s what. I left the board to poison for six hours.

Now let's talk about the results and experimental plates in more detail.

There was once a colored blue marker, nothing, it doesn’t protect the textolite, what’s with it and what’s without it, and it dried up, I took it apart, and kept the case, in such a case it will fit just perfectly for a dialing device, but now that’s not about it.

• A marker, just like an ordinary black marker
• Marker for signing CDs
• Two different pens - not gel
• And of course nail polish

So, as we can see, varnish did the best job, but it’s not convenient for painting boards, just painting on them.

Next is the marker for the CD, it did a good job, and if you don’t keep it in the solution for 5 hours, it works just as well as varnish. It has one peculiarity - the drawing part is thin, protected a little higher by plastic, and drawing under a ruler is a pleasure.

The custom marker did the same job as the previous one, only it has a slightly larger drawing tip, but it also turns out very well.

Now the pens. There is not a trace left of the pens, I once had a gel pen, and it drew so well that it was a sight for sore eyes! The result was tracks of 0.4 mm, only it disappeared somewhere, during testing I remembered this and decided to check how current pens draw.

The varnish here has only one advantage, and if you put it in a pot of sweat corrector, it’s basically a thermonuclear thing for painting circuit boards! I also have enough markers, and this is just a note.

On the pages of the site there has already been talk about the so-called “pencil technology” for manufacturing printed circuit boards. The method is simple and accessible - a correction pencil can be bought in almost any store that sells stationery. But there are also limitations. Those who tried to draw a printed circuit board drawing using a correction pencil noticed that the minimum width of the resulting track is unlikely to be less than 1.5-2.5 millimeters.

This circumstance imposes restrictions on the manufacture of printed circuit boards that have thin tracks and a small distance between them. It is known that the pitch between the pins of microcircuits made in a surface-mount package is very small. Therefore, if you need to make a printed circuit board with thin tracks and a small distance between them, then the “pencil” technology will not work. It is also worth noting that drawing a picture with a correction pencil is not very convenient, the paths are not always smooth, and the copper patches for sealing the leads of radio components are not very neat. Therefore, you have to adjust the printed circuit board design with a sharp razor blade or scalpel.

A way out of this situation may be to use a PCB marker, which is perfect for applying an etch-resistant layer. Unknowingly, you can purchase a marker for writing inscriptions and marks on CDs/DVDs. Such a marker is not suitable for the manufacture of printed circuit boards - a ferric chloride solution corrodes the pattern of such a marker, and the copper traces are almost completely etched. But, despite this, there are markers on sale that are suitable not only for writing inscriptions and marks on various materials(CD/DVD discs, plastic, wire insulation), but also for making an etching-resistant protective layer.

In practice, a marker for printed circuit boards was used Edding 792. It allows you to draw lines with a width of 0.8-1 mm. This is enough to make large quantity printed circuit boards for homemade electronic devices. As it turned out, this marker copes with the task perfectly. The printed circuit board turned out pretty good, although it was drawn in a hurry. Take a look.

PCB (made with Edding 792 marker)

By the way, the Edding 792 marker can also be used to correct errors and blots that occurred when transferring a printed circuit board design to a workpiece using the LUT (laser ironing technology) method. This happens, especially if the printed circuit board is quite large sizes and with a complex pattern. This is very convenient, since there is no need to completely transfer the entire design onto the workpiece again.

If you can't find an Edding 792 marker, it will do Edding 791, Edding 780. They can also be used to draw printed circuit boards.

Surely novice electronics enthusiasts will be interested in process making a printed circuit board using a marker, so this is what the story will be about next.

The entire process of manufacturing a printed circuit board is similar to that described in the article “Making a printed circuit board using the “pencil” method.” Here's a short algorithm:

A few "subtleties".

About drilling holes.

There is an opinion that you need to drill holes in the printed circuit board after etching. As you can see, in the above algorithm, holes are drilled before etching the printed circuit board in the solution. In principle, you can drill either before etching the printed circuit board or after. From a technological point of view, there are no restrictions. But, it is worth considering that the quality of drilling directly depends on the tool used to drill holes.

If drilling machine develops good speed and there are high-quality drills available, you can drill after etching - the result will be good. But, if you drill holes in the board with a homemade mini-drill based on a weak motor with poor alignment, you can easily tear off the copper spots for the terminals.

Also, a lot depends on the quality of PCB, getinax or fiberglass. Therefore, in the above algorithm, drilling holes occurs before etching the printed circuit board. With this algorithm, the copper edges remaining after drilling can be easily removed sandpaper and at the same time clean the copper surface from contaminants, if any. As is known, the contaminated surface of copper foil is poorly etched in solution.

How to dissolve protective layer marker?

After etching in a solution, the protective layer, which was applied with an Edding 792 marker, can be easily removed with a solvent. In fact, white spirit was used. It stinks, of course, disgustingly, but it washes off the protective layer with a bang. There are no varnish residues left.

Preparing a printed circuit board for tinning copper tracks.

After the protective layer is removed, you can for a few seconds throw the printed circuit board blank into the solution again. At the same time, the surface of the copper tracks will be slightly etched and become bright pink. Such copper is better covered with solder during subsequent tinning of the tracks, since there are no oxides or small contaminants on its surface. True, tinning of the tracks must be done immediately, otherwise the copper in the open air will again be covered with a layer of oxide.

Finished device after assembly

Out of curiosity, I bought a marker for printed circuit boards – edding 791 paint (bought at IEC for 95 rubles). They write on the Internet that it is varnished.

The marker had a tamper-evident sticker on it. To use it, you need to shake it and press the tip in a vertical position so that the ink gets onto it and saturates it.

I prepared the board, punched and drilled holes. Let's start drawing the drawing. I bought a marker with a line thickness of 1-2 mm, it is impossible to do small work with such a marker, the resulting lines are 1.5-2 mm thick. If the tracks are connected, then just wait until the ink dries and use a needle to remove the excess marker. The paths around the holes are made by briefly touching the hole with a marker; the ink from the marker spreads a little in all directions, forming a good area.

Before etching

After etching

After removing the ink.

The ink can be easily removed with alcohol or sandpaper. There are almost no etch marks under the marker; perhaps the board was overexposed.

This marker is well suited for applying, not small, designs on a printed circuit board.

A printed circuit board is a sheet of insulating material, usually fiberglass, on one or two sides of which there are conductive tracks, usually copper. The parts are inserted into holes in the board and soldered to these tracks. The conductive tracks are located in such a way that if they are correctly inserted into the required holes and soldered well, then these tracks will connect the parts together in such a way that a kind of electronic device is obtained.

There is also surface mounting, when the parts are located on the same side as the printed tracks and are soldered to them without pushing the leads into the holes. This method is most often used in very compact devices, when installing miniature parts. At home, so to speak, in kitchen conditions, it’s easier to do the first option. This is what we will talk about here.

There are many ways and methods for manufacturing printed circuit boards in “kitchen” conditions, described in various amateur radio literature. Here, without claiming originality, we consider one of them, suitable for the manufacture of printed circuit boards for simple electronic devices. As an example, we will make a board for the sound signaling device described in this magazine in the article “Electronic bell for a bicycle.” In order not to leaf through the magazine once again, the timer diagram, as well as a drawing of the printed circuit board and wiring diagram, are repeated here in figures 1, 2 and 3, respectively.

Preparing the drawing

But, before making a printed circuit board, you need to find out at what scale its drawing is given. In radio magazines, the drawing is almost always given on a scale of 1:1. But it is different in different publications.

If the board drawing is given in a different scale, it needs to be re-shot or redrawn on a scale grid, so that the image is on a scale of 1: 1. Here the image is immediately on a 1:1 scale, and nothing needs to be reduced or enlarged.

PCB material

The main material for printed circuit boards is foil-coated fiberglass. This is an insulating sheet on which copper foil is glued on one or both sides. From this sheet you need to cut a blank - a piece slightly larger in size than the printed circuit board. It is usually recommended to cut with a metal file, but if you have sufficient physical strength, this can be done with metal scissors - it will be faster and with less sweat.

Then, the foil must be carefully sanded with fine sandpaper, but not to the point of holes, but so as to remove only the layer of oxides. There is no need to achieve a mirror shine; it would be better to have a lot of small scratches. The essence of further actions is to protect from the etching solution required areas foil.

Transferring a drawing

Now you need to transfer Figure 2 to this foil. The easiest way to do this is with an awl, a light hammer, carbon paper (“carbon paper”, which is placed between sheets of paper to write on several sheets at once), and ballpoint pen.

Rice. 1. Scheme of a simple electronic device.

Rice. 2. Printed circuit board for an electronic device.

Rice. 3. Layout of components on the printed circuit board.

You need to place the blank under the sheet with the image of the tracks (Fig. 2). However, you can make a photocopy first so as not to spoil the magazine. Then, between the sheet with the image of the tracks and the workpiece, lay a carbon copy with the ink side facing the workpiece. Using paper clips or another method, secure this “sandwich”.

Next, using an awl and a light hammer, you need to slightly, just a little bit, mark the points where the holes should be. Then, using a ballpoint pen, draw the tracks so that their contours are transferred through the carbon paper to the workpiece. Now let’s disassemble the “sandwich”.

Drilling holes

We take a micro-drill (an electric screwdriver or a small screwdriver will work as a micro-drill), and use a metal drill with a diameter of 1-1.2 mm to drill holes in the punched areas. It is better to blow off the sawdust rather than brush it away with your hand, otherwise you can erase the carbon copy design. Do not paw the surface of the board on the foil side, because your fingers leave “sweat-grease” marks, which can interfere with etching in the future.

Drawing tracks

The next stage is drawing the tracks themselves. There are many ways to do this. You can use nail polish (with an appropriate brush), tsapon-varnish, nitro paint, bitumen varnish. In this case, the writing instrument is a nail polish brush, a drawing pen, a pen for drawing, a sharpened match.

But all this became a thing of the past, after felt-tip pens (markers) for writing on CDs and DVDs appeared in office supply stores.

This can be said to have "revolutionized the kitchen industry" of printed circuit boards. We take a “For CD” or “For DVD” marker, thick black, fresh, smelling “tasty” of either alcohol or acetate, and meticulously draw with it the mounting pads and printed tracks, painting their surface tightly, in several layers.

At the same time, the rest of the surface must be left unpainted (and unpatched). The mark from the For CD or For DVD marker dries instantly, so the workpiece is ready for etching immediately after the drawing process is completed.

Etching tracks

The most suitable reagent for etching is a ferric chloride solution. Now ferric chloride in powder form is sold almost everywhere in the same place where radio components are sold. You need to dilute 50-60 grams per glass of warm water.

Stir with a non-metallic object (an ordinary metal teaspoon is convenient, of course, but it will ruin everything and spoil itself). Then, having done in a corner of the board unoccupied by paths small hole, you can hang this fee for it on a nylon fishing line and lower it into this very glass (the glass must be non-metallic).

So that the board is somewhere in the middle of the glass, completely covered with a solution of ferric chloride. After all the unpainted foil has dissolved, remove the workpiece and rinse with water. Wash off the marker paint with any alcohol-containing liquid, for example... cheap cologne.

Rinse with water again, dry with a hairdryer and you can arrange the parts according to Figure 3 and solder.

lupo, well, then continue in the same way, especially since the board is custom-made, and, obviously, time is limited, and you will spend quite a lot of time on mastering LUT. My “secrets” from the days when I painted with paint:

A) use of an insulin syringe with a removable thin (pink) needle ground down (not bitten off!) to 4-5 mm.
b) use not nitro paints, but PF enamels diluted with appropriate solvents (in no case with acetone or acetone-containing solvents! - contrary to apparent logic, PF diluted with acetone will dry for a week).
c) sufficiently liquid dilution of the enamel and adjustment of the “feed” by inserting a wire into the needle - the diameter is selected experimentally - to prevent spontaneous leakage of “ink”. For the same purpose, it is not advisable to fill the syringe more than 2-3 mm above the needle level. In this case, the paint is “sucked out” from the needle due to the capillary effect only when drawing. You need to have a piece of cardboard on hand - even with a short break, you will have to “paint” the needle by inflating the syringe, and at the same time a drop will crawl out, which, if you try to “paint” the syringe directly on the board, will lead to a blot.
d) first, ALL the nickels of the contact pads are outlined, then the board is given time to dry to the point of “non-sticking” to the nickels of the ruler - at least 3 hours)
e) drawing lines is carried out under a ruler with the lower edge beveled inward - to prevent paint from leaking. In this case, according to the project, horizontal lines are first drawn (with a margin on both sides - PF, unlike nitrate, is good because it is easier to carefully clean it up until it is completely dry (even under a ruler, which is very convenient when cleaning “grids” formed with this technology, for example, on turns of multi-bit buses), then the board is given time to dry, and then vertical lines are drawn. At this moment, “forgotten” horizontal lines are usually discovered - then vertical lines are also drawn with a reserve, and in place of the missing horizontal lines. Marks are made with a BALLPOINT PEN for subsequent finishing touches.
f) after the verticals have dried, the diagonals are drawn if necessary, and you can immediately clean up smudges, “tails” of the horizontals, etc. The advantage of PF is that it retains its plasticity for quite a long time and does not chip when stripped, unlike nitrate. Thanks to this, once you have mastered the skill, you can CALMLY “draw” two tracks between the legs of the microcircuit with a pitch of 2.5 mm. 0.5 mm track if these recommendations are followed - standard width paths, with VERY great care, careful selection of paint thickness and the diameter of the insert wire - 0.3 mm can be pulled out. Will they merge with the heels of their legs? And X with them - after drying, the insulating gaps are calmly and without tension “finished” with a scraper. There is no need to try to eliminate streaks IMMEDIATELY - this will only lead to dirt on the board! Let them dry (I usually marked the resulting “strips” that required further attention in the design drawing with a highlighter marker, and eliminated them after COMPLETE drawing of the board tracks).
g) let the board dry for at least 4 hours, at least until the feeling of your finger “sticking” to the last drawn tracks disappears.
h) Well, that's it... Next - ferric chloride, final inspection and, if necessary, cleaning. The strength of the paint makes it possible, in case of high unevenness of the distribution (a very dense pattern with thin tracks in some places, and large etched areas in others), in order to avoid etching of already etched tracks, stop the general mixing of the solution and apply manual forced (with a foam swab) on large etched surfaces.
i) I wash off the paint from the etched board not with a solvent, but under a tap - using a piece of burlap and Pemoxol (or any other abrasive detergent) - this allows you to immediately tin the board with a soldering iron after washing off the paint and blotting up drops from the board, dousing it with alcohol-rosin flux (preferably activated LTI-120)
j) Enjoy!

Nostalgia... I haven't used this method for years... And if you have time and a laser printer, ask in the Search on the forums or in Google. LUT(Laser Ironing Technology), and there will be happiness. With practiced skills (not a single recommendation is a dogma, much depends on the printer, media, paper and personal preferences), this technology allows you to produce boards with a quality even higher than industrial silk-screen printing, with a very stable result. I’ll add a secret on my own behalf, which for some reason was missed in the “educational education” on LUT - with this technology, wide (power) paths and large painted areas are printed rather poorly - very ugly pinpoint etch marks occur. In this case, I usually draw all the tracks in a project wider than 1 mm and draw the “islands” of the foil only with a contour (a 0.5 mm line), after printing the design on the board, painting the inter-circuit space in the classical way - with a syringe with paint.