In detail: DIY repair of the MD coil from a real master for the site my.housecope.com.
Metal detector coils play an essential role in finding valuable finds, but with intense work, impacts on rocks and pieces of soil can leave a sad imprint on the coil design, which often leads to its replacement. Before spending money on a new coil, you can figure out what happened and try to repair the coil with your own hands.
Before interfering with the coil mechanism, check if it is still under warranty. The average warranty period for coils is about a year, therefore, in case of a breakdown within the first months after using the metal detector, you should contact an authorized service center, where the coil will be repaired free of charge. If you have been using (and quite successfully) the coil for more than a year, and there was a problem with it, you can try to repair it yourself.
First of all, you need to determine if the coil has really fallen into disrepair. Malfunctioning behavior during operation is a symptom of a malfunction. This is "dulling", and sometimes a complete refusal of the detector to fulfill its duties. The coil starts to squeak at the most inopportune moment, shows an increased or zero index, in general, behaves inadequately. Most often, on such a coil, you can find numerous chips, scratches, and cracks. It can also happen that something inside the coil seems to have fallen off. This may be due to the fact that the rubber seals holding the coil are worn out and no longer perform their function. The coil crawls along the body and, naturally, there can be no question of any sensitivity in this situation.
Video (click to play). |
First you need to prepare well - dry the coil for several hours, prepare the necessary tool. You will need:
- Sharp knife
- Epoxy (when choosing, pay attention to the color, it is advisable to choose a shade that matches the color of the coil)
- Putty knife
- Flat surface for mixing glue
- Sandpaper
This is how a well-served coil looks like - it has a lot of cracks and chips
Expand the cracks carefully with a knife. Mix both of the epoxy kit (resin and hardener) on a flat surface using a plank or discarded plate. Apply the resulting composition to the cracks of the coil, sparing no glue - the remnants can be cut off later. Now you need to wait for the epoxy to dry, which usually takes about a day. After the glue is completely dry, sand the spool body starting with the coarser structure. This will remove any unevenness from the adhesive.
In this way, you can return the coil to almost its original appearance, as well as protect it from further destruction.
As we already mentioned, the coil can simply stop working. If visually everything is in order with the case, only a professional can determine the reasons for the failure of the sensor. But if you clearly feel that something is rattling inside the coil (which should ideally not be), you can try to fix it yourself.
Most often, the seam is fused; you will have to carefully cut it along its entire length with a sharp knife.
Open the coil carefully without touching the wires.
If there is something rumble inside the coil, then you will see that the rubber seals have worn off, have ceased to hold the coil.
Attach the spool with glue or double-sided tape to the top of the case, remove the protective film if using tape. Glue the body with a good glue, such as a car glue.
If you are using double-sided tape, be sure to check its specifications.There are models of scotch tape that can withstand temperatures from -30 to +145 degrees, but you can mistakenly choose the wrong type that can only be operated at positive temperatures. With this option, your coil will not last long, and you will have to start all over again.
We told you how to repair a metal detector coil with your own hands, saving a decent amount of money, which you can spend on additional accessories.
Joint Forum of Treasure Hunters
#1 Victor_ya » 03.04.2016, 22:50
#2 nexus13 » 04.04.2016, 08:57
#3 Victor_ya » 04.04.2016, 12:11
#4 nexus13 » 04.04.2016, 13:46
look in the same place for the characteristics that you need there of this rubbish sea
although if the capacity is kondeya, then even the cheapest one will measure it
#5 Victor_ya » 04.04.2016, 20:16
continue
the next step is to determine the dimensions of the coil, and the frequency can be set to any, which will be discussed later.
we draw a coil on paper, the paper will endure everything, if suddenly it turned out not very
to be continued .
#6 wins32 » 04.04.2016, 22:11
probably it's not a secret for anyone that I collected md so that's what I mean
the coil to it must be done by yourself with a frequency spacing between TX and RX 800 - 1200
AKA does not have this yes
and the frequency is selected by capacitors according to the inductance
and the resistance has nothing to do with it
containers are easier to pick up with this
and the main reason for not doing it myself is due to the fact that the coil must be reduced and it is desirable to reduce it with the help of an oscilloscope
Or are AKA coils not converging?
mixing by the way is done in the coil body
#7 Victor_ya » 04.04.2016, 22:26
comrades I have assembled the coil, it works, everything is ok, so bear with me a little
Added after 1 hour 14 minutes:
will continue
before winding, the question arose - how many turns? there is a special program, but I did not understand it, and did it my own way, if there are a lot of wires, then you can wind, for example, 10 turns, measure the resistance and calculate the number of turns by 10-12 ohms with a small margin , I had a demagnetizing loop with a resistance of about 12.5 Ohm, I waved the whole thing, it turned out to be 200 turns, it turned out to be too much and very thick, I decided to wind it up, stopped at 160, the resistance turned out to be exactly 10 Ohm,
the amount is known, you need to wind the second one, the coils wind in one direction and that the ends are in one place you need a ”winding
Added after 22 hours 53 minutes:
so the coils are wound, we wind them well with a thread so that the turns fit tightly to each other, although some of them tighten only in several places, so the coil is more pliable when stacked on top of each other and is impregnated when filled with resin better, so I can't say which is better ...
then you need a connector, wire, capacitors. I had to look for the connector, and I did not find an ambush with a wire, such as on the coils (four-core, each pair in its screen, people use it in the general screen, they also did not find it), bought a two-core one, collected all the capacitors that were, we need thermostable film ( 47N 0.1mk 0.22mk 0.33mk 0.47mk) I bought something in addition, experiments
we make connections according to the diagram below, but only while the Tx circuit (the capacitor to the coil is connected in series to pin 3, it is very important not to confuse) and connect to the MD, the MD will show the frequency of the coil, select the capacitor until the desired frequency is obtained
to be continued.
#8 Victor_ya » 06.04.2016, 23:03
to configure the receiving coil Px circuit (capacitor in parallel), you will need an auto-generator, which we assemble according to the diagram below, the most problematic is to find transistors kt326B (or 2t326B), it is not in the magazines, a familiar radio amateur helped.
with the help of an auto-generator, the circuit is excited and you can measure its frequency, you will need a frequency meter for measurement, expensive multimeters have it, I used VC9808 + (it has everything you need), it was lent to me by a friend of my comrade Lyokha from our forum, the main thing is to accurately measure the frequency, a cheaper device deceived me by a whole kilohertz, selecting capacitors we achieve a frequency less than that of the Tx circuit by about 200 Hz, the OFFSET is MANDATORY.
Added after 23 hours 23 minutes:
so, the coils are configured, we solder the cable to the plug and to the coils as in the diagram from the 7th post, put the coils on paper on top of each other by 2-3 cm (this option is for pouring the coils into foam, the option with the finished case is slightly different), further away from metal and
we connect to the MD. at the points of contact of the coils, you need to put pieces of fabric
now you need to reduce the coils, that is, to achieve a minimum voltage between them, usually this is done using an oscilloscope, but you can also use a multimeter. we translate the cartoon into the measurement of an alternating voltage of 2 volts and connect the probes to the Px circuit, turn on the MD, but first make the chuyka smaller (half or slightly less), after turning on all the devices, the voltage value will appear on the multimeter, after which we begin to move very slowly the coil which is on top (usually Px), we achieve a voltage reduction to 0.1-0.2 volts and translate the measurement limit to 200 millivolts and continue moving even more slowly until a value of 5-10 millivolts is obtained (the less the better), after which we outline the boundaries of the coil with a pencil with a small margin, cut out the template, put it on the foam and circle it with a marker, then cut it out with a clerical knife
#9 Victor_ya » 10.04.2016, 23:01
contour addition Px
after the coils have been tuned and preliminarily reduced, you need to check the soil balance for ferrite, it should be within -10 +10, if it does not converge, then we try to select a capacitor
Added after 17 minutes 10 seconds:
the foam was cut out, in the area of the sealed entry we pierce the foam with a copper puddle wire (the diameter is somewhere 0.3 mm, twisted and tinned three thin hairs), so that there would be 20 cm on both sides, this wire will be soldered to contact No. 2 and will serve contact for the graphite screen, then fill in the base on which the coils will be laid, about 3 mm of epoxy resin, after drying we lay the coils, bring them together, fix them with hot melt glue at several points
#10 Victor_ya » 12.04.2016, 23:32
the distance between the coils was enough for the ears, I carved the ears out of ABS plastic, made them double, the first between the coils, the second above the coils, see the photo, in the first, in the lower part I made several holes so that the resin would flow, it will be stronger.
pouring epoxy resin must be done in two or three passes, pour the windings first and let dry for 5 days.
after pouring, the parameters of the coils will go away, the “mixing” voltage will start to grow, I managed to initially reduce it to 5mV, after pouring in a day it became 40mV, after three it was already 120mV, a small coil wound on two fingers, 10 turns and connected in series, will help to return the voltage back to pin 4 of the Tx coil (pre-tied with a thread, smeared with resin and dried), connect and start moving between the coils, catch the voltage drop in the Px circuit to the minimum, the correct connection of this coil is of great importance, if there is no decrease, then you need to turn the coil and change the ends , after we fix it and fill it again, after drying, we check the voltage again, I reduced it to 4mV with this coil, after filling it took up to 8mV, if the voltage is still high, you can lower it with a small piece of ferrite, just drive and look for a place (some do not turn with a small coil , and ferrite is used)
#11 Victor_ya » 14.04.2016, 23:29
then we cut off the polystyrene, grind the excess resin as much as possible to reduce the weight, lay the tin, fix it (I use poxypol), knead the graphite powder with nitro lacquer NC (for two tablespoons of varnish,half a spoon without a slide of graphite) mix and quickly apply in two layers (we do it on the street, very smelly varnish and dries quickly), graphite can be found on the railway IN DEPO (graphite pantographs from electric locomotives), it needs to be ground off with a large file or a drill with a large with a drill, a day after application, we check the resistance of the graphite screen, at different points (we hold one probe on a tin, and we poke around in different places) the resistance should turn out to be approximately in the region of 1 kOhm
#12 vladimi78 » 17.04.2016, 20:21
#13 Victor_ya » 17.04.2016, 21:28
after which I covered the whole coil with epoxy to protect the screen, also covered the sides and bottom with anti-gravel and now I'm redoing the entrance to the coil, because I found the cable, the final photo will be a little later and there will be a small addition, because I made a small mistake, but fixed it
#14 wins32 » 17.04.2016, 22:10
#15 Victor_ya » 17.04.2016, 23:18
the weight of its main minus, I don’t remember exactly, in my opinion 720, if I do more, I’ll already order the case, there the weight will be less, well, how the factory will look
Added after 22 hours 52 minutes:
I can't upload a photo, squeaks
The maximum total size of your investment has been reached.
Added after 23 hours 51 minutes:
Well, I'm ready, I'll be testing this weekend
about the mistake I made, the frequency offset of the Px circuit must be done at 500 hertz somewhere (by selecting a capacitor I set the ground balance to ferrite -3, before that it was +65), initially I made 200, the coil worked properly, but the ground balance was wrong , while the signum did not care, the view was normal and it even seemed that the depth through the air was greater
#16 Victor_ya » 07.09.2016, 23:07
I ordered such a set, I will make a sniper rifle, I use an old stand for winding, I circled the body with a pencil, figured out how the coils would lie, stuffed nails and go
ps what I wrote earlier when making the first coil can be partially forgotten, a lot of unnecessary
#17 Victor » 08.09.2016, 08:41
#18 Victor_ya » 08.09.2016, 21:57
So a new problem with the breakdown of search equipment overtook me. This time the coil has already broken. That important component of the device, without which the search is simply physically impossible. Without a coil, the head of a metal detector is just a set of chips.
As is usually the case, the breakdown came unexpectedly. It was the very day of the cop at the settlement. At first, the device behaved quite well. He only squeaked lazily at the shaking md. Several finds have been dug up, everything is fine. But with each passing minute, MD behaved worse and worse. More and more often he gave empty phantom signals. The weather that day was wet, snow and rain. That I was even soaked myself. Then ICQ was just beeping at everything incessantly. That's it, the device is bent!
The reason for the breakdown turned out to be quite commonplace - water seeped through the fill to the windings. While driving home, I made plans to repair the coil: dry it and fill the cracks with epoxy. But at home he changed his mind and still decided to thoroughly repair it! Namely, overfill it.
What are the prerequisites for a breakdown? One of the most basic is the use of such a material as a fill, which does not adhere well to the plastic body of the coil. And under the influence of external factors, it lags behind the body and cracks appear. Also, this fill itself is fragile. It may not withstand impacts on stones and trees. You can use protection, but it will not prevent damage to the fill, but will only delay it for some time. This is, of course, if the device is used by a really stubborn treasure hunter.
Further, the process of repair began. If you have never held the instrument in your hands, or are afraid to completely ditch the coil, then it is better not to repair it yourself.
- The first stage we have is the hatching of the factory fill. Where she lags freely, and where you need to use force. Use a sharp knife to pry the fill and try to pull it out from there. You need to start from those places where the fill has already cracked. And gradually and leisurely to remove it. Don't overdo it with the knife! The coil windings are in soft hot melt glue. You can safely damage them. Note the exposed black color. This is a graphite screen. Your job is not to damage it or to let as little graphite come off as possible.If you ripped it off, then it would be better to restore it with the help of graphite brushes from power tool motors, ground into powder and mixed with varnish. With a damaged graphite screen, especially if too much of it has gone, the device will give phantoms. After dismantling the factory fill, dry the coil again.
- After removing the fill, a bare wire will stick out from the inside. This is the screen. It must be bonded to the graphite layer. This requires a conductive adhesive.
- Having connected the wire to the screen, degrease the plastic edges, for example, with alcohol. We need this for better gluing of the two-component epoxy glue with the plastic sides of the coil.
- For greater strength of the pouring, I made a reinforcement of gauze. I just cut out strips of bandage and spread them all over the spool. We get a kind of internal protection that will multiply the strength and prevent our new fill from cracking from the inside.
- After being reinforced with a bandage, the coil is ready for casting. Install it evenly so that the epoxy spreads evenly over the entire area of the coil, there are no smudges and there are no bumps and depressions in it. We dilute the epoxy according to the attached instructions and carefully pour it into the coil, making sure it spreads evenly. Fill with glue with a hill. So that he also grabs the upper part of the sides of the plastic case.
- Well, now we are waiting! According to the instructions, the two-component epoxy adhesive cures for 24 hours. After 24 hours, we calmly test the coil for stability. Everything is fine, then it's done! You can also remove any sharp spots and burrs with sandpaper. And cover it on top with protection or anti-gravel. I had one more problem - the wire in the plug was soldered again. He soldered it again, put on a heat shrink and filled the contact area with the wires with hot glue from a gun. Just the place. which is covered with a piece of transparent insulation.
Well, in the field, she already looked like this.
In my garden, the device gave phantoms. When I shook and twisted it, it still beep. I wrote it off to the city. And in the field, in an abandoned village, the device behaved like new! Phantoms 0, not a single falsehood. Finds came across, the repaired coil hooked on a silver wedding ring. In general, I am satisfied with the repair! Despite the fact that a new coil of the same costs 10 thousand rubles!
But history has recently repeated itself almost one to one, but only this time with a sniper ... However, this is a completely different story.
I also advise you to subscribe to the Staraya Vyatka channel, where you will find a lot of videos about detecting, metal detectors, navigation, cartography and coin care:
Since those distant times, when my friend was making his first steps in treasure hunting, he had a Garrett ACE 250 metal detector with a 9 by 12 inch coil, he used it for a long time and successfully, but after that he bought a Minelab X-Terra 705 and no matter what his first I did not sell the metal detector, I used it as a training device for friends who wanted to try their hand at treasure hunting. Over the long period of such use, the metal detector coil had worn out, cracks appeared on it, in general, it was impossible to operate the coil in this form, although nominally it remained a working metal detector and settled in the garage and lay in the farthest and darkest corner. And then a friend asked for my help in repairing the coil.
The lower part of the coil at the point of filling was in a terrible state, two rather large cracks with a bottom length of one to one and a half centimeters and a large crack on the side of the coil.
To repair the bottom layer of the coil, we need:
- Incandescent lamp.
- Stationery knife.
- Two-component adhesive (epoxy resin).
- Small spatula.
- Glue mixing pad.
- Medium and fine emery.
The first thing that had to be done before repairing the coil was to dry it properly, for this I kept it under an incandescent lamp for about 10 hours. Then, using a clerical knife, I very carefully expanded the cracks on the coil.
I squeezed out two-component glue from two tubes on a plate and mixed the two substances with a spatula. Using a spatula, carefully spread the resin onto the spool. In places subject to resuscitation, do not spare the resin, you can apply "with a slide" all unnecessary, we will remove later. In order for the resin to dry, you must give it at least 24 hours. After that, treat the bottom surface of the coil with emery, first coarser, after fine. Processing the coil with emery will remove all new irregularities, as well as small and medium scratches, which, purely outwardly, will very refresh the coil.
When choosing a two-component glue, I did not pay attention to its color, as it turned out I came across gray. To observe purely external harmony, it is worth choosing a glue whose color matches the original filling of the coil.
This is how the former problem areas on the coils look like; after the surface treatment, the coil surface became even and smooth. After such a procedure, she can even be used in an underwater search, she won’t care.
As you can see, there is nothing difficult to repair the bottom surface of the metal detector coil, it can be done even at home with a minimum of money.
If you do not have a new XP Deus X35 coil, if your coil is not a high-frequency blonde Deus HF, and you still have an old regular coil in use, do not rush to install the XP Deus 5.1 firmware. There is a chance the firmware will kill the coil. The commentator edukol shares his experience. Continue reading →
Great goldfinches. Today we will make XP Deus with our own hands. We'll need ... three completely dead XP metal detectors, some glue, old packaging ... I am sharing the secrets of how to revive the XP Deus. And don't care if this zombie only lives for 30 days. Enough for us. Do you need money? Continue reading →
Some manufacturers will now have something to learn ... Remember the Hellish ICQ, which found the treasure? It clearly lacked one detail. Namely, a search coil made of a teapot stand ... Don't rush to laugh, you may have to cry. If a metal detector coil can literally be made from trash, what are you paying $ 150 and $ 200 for? Some even want $ 1,500 reels. Well, aren't they stupid? Buy a kettle for $ 10 and don’t suffer. Do not know how to make a coil out of a teapot for your detector? Look. It's simple! Continue reading →
Some metal detector experts (such experts really exist, these are not just nice words) shared critical reviews with the advent of the XP Deus 28 coil. The coil was openly criticized, not advised, and in general for the XP manufacturer it was a good lesson from the diggers. But as you can see, the coil is still on sale today. To XP's credit, it should be said that criticism was accepted, the dissatisfied were not banned or kicked to the edge of the Internet, and as a result, the coil was finalized to a working condition. Interesting video review of XP Deus 28! Continue reading →
Minelab has named its Minelab Equinox coils smart. And in general, half of the metal detector is in these very coils. You understand that the price of such a reel will be big, no need to be surprised ... What Minelab says is of course interesting, but you still can't hide the truth. And I just want to exclaim. Minelab, are you serious? We are looking at cool photos, the coil of the new Minelab Equinox metal detector under X-ray. Continue reading →
I decided to assemble my first pulse metal detector Clone PI-W and, so, it came to making a mono search coil. And since I am currently experiencing some financial difficulties, I was faced with a difficult task - to make the coil myself from the cheapest materials.
Looking ahead, I will say right away that I coped with the task. As a result, I got the following sensor:
By the way, the resulting ring coil is perfect not only for Clone, but also for almost any other impulse (Koschey, Tracker, Pirate).
Next, I will tell you how to make a search coil for a metal detector with your own hands, spending less than 500 rubles on it.
I will tell you in great detail, since the devil is often in the details. Moreover, there are a dime a dozen short stories of making coils on the internet (like, we take this, then we cut it off, wrap it, glue it and it's done!) ... And it turns out that everything is more complicated than it seemed at the very beginning.
This will not happen here. Ready? Go!
The easiest way for me to make it myself was this design: we take a disk made of sheet material with a thickness
4-6 mm. The diameter of this disc is determined by the diameter of the future winding (in my case, it should be equal to 21 cm).
Then, on both sides, glue two discs of a slightly larger diameter to this pancake, so that it looks like a spool for winding wire. Those. such a greatly increased diameter, but flattened in height coil.
For clarity, I will try to depict this in the drawing:
Hope the main idea is clear. Just three discs glued together over the entire area.
I planned to take plexiglass as a material. It is perfectly processed and glued with dichloroethane. But, unfortunately, I could not find it for free.
All sorts of collective farm materials such as plywood, cardboard, bucket lids, etc. I immediately discarded it as unusable. I wanted something strong, durable and preferably waterproof.
And then my gaze turned to the fiberglass.
It's no secret that anything your heart desires is made of fiberglass (or glass mat, fiberglass). Even motor boats and car bumpers. The fabric is impregnated with epoxy resin, shaped and left to cure completely. The result is a durable, water-resistant, easily recyclable material. And this is exactly what we need.
So, we need to make three pancakes and ears for attaching the bar.
Calculations have shown that to obtain a sheet with a thickness of 5.5 mm, you need to take 18 layers of fiberglass. To reduce the consumption of epoxy, it is better to pre-cut the fiberglass into circles of the required diameter.
For a disc with a diameter of 21 cm, just 100 ml of epoxy was enough.
Each layer must be thoroughly smeared, and then put the entire stack under a press. The higher the pressure, the better - the excess resin will be squeezed out, the mass of the final product will be a little less, and the strength will be a little more. I loaded about a hundred kilograms on top and left it until morning. The next day, we got a pancake like this:
This is the most massive part of the future coil. He weighs - be healthy!
Then I'll tell you how this spare part can significantly reduce the weight of the finished sensor.
A disc 23 cm in diameter and 1.5 mm thick was made in exactly the same way. Its weight is 89 g.
The third disc did not have to be glued. At my disposal was a sheet of fiberglass of a suitable size and thickness. It was a printed circuit board from some ancient device:
Unfortunately, the board had plated holes, so I had to spend some time drilling them.
I decided that this would be the top disk, so I made a hole in it for the cable entry.
The remains of the PCB were just enough for the ears to attach the sensor body to the rod. Sawed two pieces in each ear (to keep it strong!)
In the ears, you need to immediately drill holes for a plastic bolt, since then it will be very inconvenient to do this.
By the way, this is the fixing bolt for the toilet seat.
So, all the components of our coil are ready. It remains to glue it all into one big sandwich. And don't forget to put the cable inside.
First, I glued the upper disk made of leaky fiberglass with an average pancake of 18 layers of fiberglass. It took literally a few milliliters of epoxy - this was enough to smear both glued surfaces over the entire area.
Using a jigsaw, I sawed off the grooves. In one place, of course, I overdid it a bit:
To make the fish soup well, I made a small bevel at the edges of the cuts:
Now you had to decide which option is better? Ears can be placed in different ways.
Commercial coils are more often made on the right side, but I prefer the left one. In general, I often make left-wing decisions.
In theory, the right way is better balanced, tk. the bar mount is closer to the center of gravity. But it is far from the fact that after the coil is lightened, its center of gravity will not shift in one direction or another.
The left mounting method looks visually more pleasant (IMHO), and in this case, the total length of the metal detector when folded will be a couple of centimeters less. For someone who plans to carry the device in a backpack, this can be important.
In general, I made my choice and proceeded to pasting. I spread it liberally with bauxite, securely fixed it in the desired position and left it to harden:
After hardening, I sanded everything sticking out from the back side with sandpaper:
Then, using a round file, I prepared grooves for the conductors, brought the connecting cable through the hole and glued it tightly:
To prevent strong bends, the cable at the entry point had to be reinforced somehow. For these purposes, I used, from where I got it, this rubber stuff:
It remained to glue the third pancake (bottom).
It took a few milliliters of bauxite to glue the third pancake and a couple of hours of time for everything to set. Here's the result:
An enameled copper wire 0.71 mm in diameter was used as a winding wire. After winding 27 turns, the sensor became 65 grams heavier:
Now the winding had to be caulked somehow. I used a mixture of epoxy resin and finely chopped fiberglass as a putty (I learned about this super-duper recipe from this article).
In short, I cut a little fiberglass:
and coolly mixed it with bauxite with the addition of paste from a ballpoint pen. The result is a viscous substance, similar to wet hair. With this composition, you can cover up any cracks without problems:
Pieces of fiberglass give the putty the required viscosity, and after hardening, provide increased strength of the glue line.
So that the mixture is properly compacted, and the resin soaked the turns of the wire, I wrapped it all with electrical tape in an interference fit:
The electrical tape must be green or, at worst, blue.
After everything had solidified well, I wondered how solid the structure was. It turned out that the coil can easily support my weight (about 80 kg).
In fact, we do not need such a super-strong coil, its weight is much more important. Too much mass of the sensor will definitely cause pain in the shoulder, especially if you plan to conduct a long search.
To reduce the weight of the coil, it was decided to cut out some sections of the structure:
This manipulation made it possible to lose 168 grams of excess weight. At the same time, the strength of the sensor practically did not decrease, as can be seen from this video:
Now, in hindsight, I understand how it was possible to make a coil even a little easier. To do this, it was necessary to pre-make large holes in the middle pancake (before gluing everything). Something like this:
The voids inside the structure would hardly affect the strength, but they would reduce the total weight by another 20-30 grams. Now, of course, it’s too late to rush about, but for the future I will take it into account.
Another way to simplify the sensor design is to reduce the width of the outer ring (where the wire turns are laid) by 6-7 millimeters. Of course, this can be done now, but so far there is no such need.
I found an excellent paint for fiberglass and fiberglass products - epoxy resin with the addition of a dye of the desired color. Since the entire construction of my sensor is made of bauxite, the resin paint will have excellent adhesion and will fit like a native.
I used PF-115 alkyd enamel as a black dye, adding it until the desired hiding power was obtained.
As practice has shown, a layer of such paint is held very firmly, and it looks as if the product was dipped in liquid plastic:
In this case, the color can be any, depending on the enamel used.
The total weight of the search coil with the cable after painting is 407 g
After our homemade metal detector coil was completely ready, it was necessary to check it for an internal breakage. The easiest way to check is to measure the winding resistance with a tester, which should normally be very low (maximum 2.5 Ohms).
In my case, the resistance of the coil, together with two meters of the connecting cable, turned out to be in the region of 0.9 ohms.
Unfortunately, in such a simple way it will not be possible to identify the turn-to-turn closure, so you have to rely on your accuracy when winding. A short circuit, if any, will immediately manifest itself after starting the circuit - the metal detector will consume an increased current and have an extremely low sensitivity.
So, I think that the task was completed successfully: I managed to make a very durable, waterproof and not too heavy reel from the most waste materials. List of expenses:
- Fiberglass sheet 27 x 25 cm - free;
- Fiberglass sheet, 2 x 0.7 m - free;
- Epoxy resin, 200 g - 120 rubles;
- Enamel PF-115, black, 0.4 kg - 72 rubles;
- Winding wire PETV-2 0.71 mm, 100 g - 250 rubles;
- Connecting cable PVS 2x1.5 (2 meters) - 46 rubles;
- Cable entry - free of charge.
Video (click to play). |
Now I am faced with the task of making exactly the same rogue barbell. But that's a completely different story.