Hello. Today I will talk about the GY910 thickness gauge. Why is he needed? It is used to determine the coating thickness of magnetic and non-magnetic metals, determine the thickness of metal painting in the automotive, aircraft and shipbuilding industries, determine the coating thickness of metal structures in everyday life (for example, windows, doors), measure the thickness of varnish on copper tracks in the production of printed circuit boards, fast detection of metal parts at the input control, search for metal defects without damaging the paint when buying a used car, measurement of metal oxide film. If you are interested - welcome under cat.
The product was delivered by courier service in 20 days. The thickness gauge is supplied in a cardboard box:
The kit includes instructions, including in normal Russian:
Iron and aluminum plates, as well as a set of calibration plates of various thicknesses:
And, before I move on to the thickness gauge itself - its brief technical characteristics:
GY910 Thickness Gauge Features:
Compact and lightweight - you can always carry with you;
Automatic shutdown to save energy;
Switching between units of measurement;
Automatic metal type recognition.
Specifications:
Measuring principle: electromagnetic induction and Foucault eddy currents;
Measuring range: from 0 to 1300 microns;
Measurement step: 1 micron;
Measurement accuracy: ±(3%+2 µm) / ±(3%+0.078 mil);
Measurement limit: 0-999 µm (1 µm) / 1000-1300 µm (0.01 mm);
Calibration: zeroing, multi-stage manual calibration;
Units: µm, mm, mil;
Minimum concave radius of curvature: 25mm;
Maximum convex curvature radius: 1.5mm;
Measurement zone radius: 3 mm;
Minimum substrate thickness: Fe (0.5 mm) / NFe (0.3 mm);
Power supply: 2 batteries 1.5V AAA;
Environmental conditions: 0°C to 40°C at 20-70% RH;
Storage conditions: -20 to 70°C;
Dimensions: 117x30x22.5 mm;
Weight: 65 gr.
GY910 Thickness Gauge Package Contents:
Thickness gauge LKP GY910;
User manual in Russian;
A set of calibration plates from 50 to 1000 microns;
Iron gauge plate (Fe);
Aluminum calibration plate (NFe);
Lace on hand;
Package;
On the front side of the thickness gauge there is an LCD screen, a calibration button and an On/Off/OK button. The procedure for multi-stage calibration is described in detail in the instructions. I will check the thickness gauge as it is, with factory calibration.
On the back there is a compartment for two AAA batteries, batteries are not included:
When the batteries are low to an unacceptable level, the battery indicator on the screen will flash. The batteries need to be replaced as this will greatly affect the measurement accuracy. This point is specifically discussed in the instructions.
At the upper end of the thickness gauge there is an electromagnetic eddy current sensor, which measures the coating thickness:
To measure the thickness of coatings on magnetic materials (Fe), both magnetic induction and the Hall effect are used, which makes it possible to measure the magnetic field density. To create a magnetic field, a soft ferromagnetic rod with a coil is most often used. Also, in turn, a second rod with a coil is used to detect any changes in the magnetic flux. The coating thickness is determined by measuring the magnetic flux density. The permissible percentage of measurement error for devices of this type is ± 3%.
The eddy current principle is used to measure the thickness of coatings on non-magnetic materials (NFe). An alternating magnetic field is generated on the probe surface of the device with the help of a current (with a frequency from tens of kHz to a few MHz) passing through a coil on which a thin wire is wound. When the probe approaches a conductive surface, an alternating magnetic field generates eddy currents (Foucault currents) on it. Eddy currents create their own (opposite to the primary) electromagnetic fields, which can be measured by the main or secondary winding. The eddy current method is mainly used for highly conductive surfaces, in particular those made of non-ferrous metals (eg aluminium). The voltage value on the measuring winding (the measured value) depends on the distance from it to the electrically conductive surface, which is the thickness of the non-conductive coating.
The type of material, Fe or NFe, is automatically determined by the thickness gauge.
Let's open the thickness gauge:
The thickness gauge uses a precision op-amp from Texas Instruments and a carry-through binary counter from NEXPERIA:
The “heart” of the thickness gauge is the microcontroller:
We insert batteries into the thickness gauge:
Units of measurement are changed by briefly pressing the power button, microns, millimeters (pictured) and milli inches are available:
You can turn off the thickness gauge by pressing and holding the power button, or if you do not touch it, then after five minutes it will turn off by itself.
Let's check the accuracy of the measurements with the supplied calibration plates.
Magnetic material (Fe):
Non-magnetic material (NFe):
Let's move on to the test on the car. The test was carried out on a friend's car. The car is practically new, bought second-hand, "unbeaten, unpainted." Or rather, a bit, already with my friend, the autolady crushed his fifth door. Video, unfortunately, will not. An acquaintance forbade him to spread, after examining the car, and he still had to sell it.))) Others also did not agree to this. Therefore, only a few black and white photos, so as not to shine the color of the car. Just in case.
Measurements are very easy to carry out, no need to lean towards the thickness gauge and try to see the readings when it is leaning against the car. We smoothly apply the sensor to the place of interest and after a couple of seconds we sharply pull it back by at least 5 centimeters from the body of the car. The current readings will remain on the screen.
So, for the first time in my life I checked the car. It took me five minutes to identify the main jambs. This time is enough to check all the main elements by going around the car in a circle. Of course, if I had spent more time, I could have found some little things, but why is this in this case? And the case is interesting.
I started with the hood, on the driver's side of the windshield. And right away - luck (though luck, depending on whom):
Nice layer of putty.
The rest of the hood was not puttied:
There will be no more photos, because it will be possible to determine the make of the car from the photo.)
I continued walking around the car in a clockwise direction. On the fifth door, I found putty left over from the meeting with the autolady, the owner of the car confirmed that everything was for sure. I go around the car further and get to the driver's door. The door was almost completely covered with a good layer of putty. Further it turned out that the left front fender was changed, it probably cost more to fix it. This was revealed by the layer of paint, which is different in thickness from all other painted parts of the car. Probably, the blow fell on the driver's door and fender, at the same time the hood was damaged. And also during the inspection it became clear that the car was repainted, with the exception of the roof. Only the original paint remains on the roof. This is easy to understand by the thickness of the paint, and also by the fact that non-factory painting is uneven in thickness, unlike factory painting. Moreover, the color was chosen amazingly, and it was clearly a specialist who straightened and puttied. Even the reflection of the impact is not visible. Well, what about, "nebit-nekrashen" ...))) I upset the owner. A thickness gauge upon purchase would have helped with this, saving money.
Thank you for your attention.
The product was provided for writing a review by the store. The review is published in accordance with clause 18 of the Site Rules.
I plan to buy +13 Add to favorites Liked the review +6In the process of searching for a used car suitable for me, I was faced with the need to check the paintwork (LCP) for uniformity, to identify painted or putty parts. At first, a professional paintwork thickness gauge fell into my hands, but they didn’t give it to me for long, and the process of finding a car, on the contrary, was stretched out in time. The meter had to be returned to the owner, and a suitable machine was not found.
Is it possible to make the simplest paint thickness gauge yourself?
The first result of an Internet search was a classic circuit based on a two-winding transformer with an open magnetic system.
A signal is applied to the primary winding, and a signal is sent to the meter from the secondary winding. The measured sample closes the magnetic system and the thicker the paint, the less the connection between the windings, the lower the output signal. But it was too lazy to look for suitable iron for the transformer and wind it, continued the search. In addition, such schemes have a strong nonlinearity in the dependence of the signal level on the coating thickness.
Then I came across a circuit that works based on a change in the inductive resistance of the sensor. A calibrated signal (preferably sinusoidal) is applied to the measuring coil, the coil is included in the arm of the measuring bridge, after zero is set, the measurement is taken.
Couldn't it be even simpler? The train of thought is something like this: "if the sensor is an inductance, then you need a device for measuring inductance"
I also remembered that I have several Arduino boards lying around. Took a couple of years ago to play.
I formulated, for myself, the task - "Measuring the inductance on the Arduino with a minimum of attachments."
As a result of searching, I came across the page https://github.com/sae/Arduino-LCQmeter/blob/master/LC-gen.ino
this program became the prototype of the simplest LKP meter.
As the main board, Arduino nano was chosen for its small dimensions.
The essence of the work is as follows: a “pump” pulse is applied to the measured LC circuit, after which the counter is started until the signal on the circuit passes through the “0” of the comparator, after which the process is repeated.
As a result, the counter reading is proportional to the resonant frequency of the LC circuit.
At first I tested the idea on the table, with the output of information to the computer. It seems to work
Although I had an LCD module, but with it the device turned out to be bulky and required the manufacture of a case.
I decided to make an indication of the thickness on the LEDs.
I drew a diagram, soldered the shield on a breadboard, provided for battery voltage control.
The problem turned out to be the manufacture of the coil. If I found many and different cups of ferrite armor cores, then I did not find a single coil frame. After several attempts to make the frame myself, the following solution was found: two cardboard cheeks were installed on the conical body of a ballpoint pen, and approximately the appropriate number of turns were wound to fit inside the core. The wire took the minimum thickness that was at hand (about 0.08), I don’t remember the number of turns, something around 100. After winding, I removed one cheek. and pushing the other cheek, he placed the resulting coil inside the core. Dropped coils, tucked into the coil with tweezers. After that, he dripped superglue onto the coils and closed the coil with the remaining cheek. I fixed the coil on the board with hot glue.
The capacitor is preferably metal-film, but not ceramic, since ceramics of such a capacity have an unacceptable TKE
As a result, we got this design:
Program text for download:
Working with the device:
Since different machines have different paint thicknesses, the calibration procedure is done first. In addition, the calibration procedure makes it possible to reduce the influence of temperature on the measurement results. To calibrate, you need to press the device to the surface of the car, and press the "calibration" button
After the calibration, the value of the thickness of the paintwork, expressed in "arbitrary units" is written to the eeprom.
to carry out the measurement, the device is applied to different places of the car's paintwork and the "Measurement" button is pressed. If the deviation of the measured result from the recorded one is small, the green LED lights up.
If the deviation exceeds a certain limit - the white LED lights up - "suspicious"
If there is a second layer of paint, or there was polishing, one of the blue "paint" or "polishing" lights up
If the coating is close to zero or exceeds 0.2, then the red LEDs "putty" or "metal" light up
Each thickness measurement is taken 3 times and then the value is averaged. Perhaps once is enough. This will allow you to get results almost instantly.
Do not consider this craft as a sample of the finished product. This is just an example of how you can solve the problem with "improvised" means. But, I suspect that on the basis of this meter, you can make a meter with professional accuracy. To do this, you will need to wind the coil with high quality, select a capacitor with a minimum TKE, connect the screen module, select the formula for converting the "raw" value into micrometers.
Boris Padorin, LLC "Dolina-Service"
When carrying out work related to painting metal surfaces, it often becomes necessary to determine the thickness of the car's paintwork. There are several ways to do this.
In industrial production, as a rule, ultrasonic thickness gauges are used for this, which operate on the principle of echolocation. A sensor is applied to the paintwork, which is essentially a piezo transducer, which receives a series of ultrasonic pulses. The ultrasonic electrical signal travels through the car's paint and then reflects off the steel surface.
The reflected electrical signal is recorded by the sensor and fed to the phase detector, which compares the phase of the sent and reflected pulses, and then generates a signal commensurate with the delay time, and hence the thickness of the paint.
This method is quite accurate, but extremely difficult for self-production. It is much easier to make a thickness gauge based on inductive or capacitive sensors.
If the coating is paintwork, then it is possible to use a capacitive sensor, which consists of two small metal plates. They are attached to a dielectric substrate and are applied to the surface under study.
Between the plates, the actual capacitance is measured, which is directly dependent on the dielectric constant of the car's paintwork and its thickness. Calibration of the thickness gauge should be performed for each type of paintwork.
The most convenient to use inductive sensors. Such a sensor is essentially a miniature E-shaped transformer, made on one side of the coil, without end plates. If the open side of such a sensor is applied to the surface under study, then the thickness of the non-magnetic gap created by the paint coating changes the inductance of this coil.
One of the measurement methods is that the coil is used as an LC - LF generator. The electrical signal is fed to the frequency detector, and then to the display module. The method is not bad, but rather complicated. The electrical circuit of a simple car thickness gauge, but quite accurate, is given in this article below.
Vehicle Paint Thickness Gauge - Description
A device for measuring the thickness of the car paintwork is a generator of constant frequency and amplitude, in series with the output of which an inductive sensor is connected. The voltage after the sensor is detected, normalized and fed to the display unit.
To display the information received, it is possible to use a small-sized dial indicator by calibrating its scale, but LED indication is more suitable.
In this thickness gauge, a transformer from a subscriber loudspeaker is used as a sensor. As mentioned above, the transformer is not closed and is impregnated with epoxy resin together with other radio elements in a case of suitable dimensions.
The working part of the sensor is polished to a shine. The advantages of the device are its small size and the ability to determine the thickness of any non-magnetic paint coatings, even coatings that can conduct electric current, for example, the thickness of aluminum spraying or copper plating on a steel surface. The thickness gauge is calibrated using plates (non-magnetic) of a predetermined thickness.
Details of the coating thickness gauge
In the electrical circuit, it is possible to use various operational amplifiers with low current consumption and low supply voltage. For the used op amps, the resistance values between pins 4 and 8 determine the current consumption and are 1 ... 1.5 MΩ.
It is possible to use dual op-amps, for example LM358 or similar. The K561LA7 chip can be changed to K561LE5 or arbitrary inverter logic elements. If it is necessary to increase the accuracy of the ADC, instead of a digital microcircuit, it is possible to use a LM339 quad comparator. It is possible to significantly simplify the electrical circuit by using the A277 chip (K1003PP1) for linear light indication, although the current consumption will increase.
In this case, the K561LA7 and KR1533ID3 microcircuits, together with the strapping resistances, will not be needed - the input contact of the microcircuit is connected to the output of the second op-amp. in the circuit it is used not only as a stable frequency generator for an inductive sensor, but also as a negative polarity inverter to create a voltage of -2 volts, which is necessary for the normal operation of the operational amplifier.
An unmistakably assembled electrical circuit begins to function immediately - it remains only to individually calibrate the LED indication of trimming resistances and non-magnetic plates of a predetermined thickness.
In this article, we will tell you about the paintwork thickness gauge (diagram).
I once sold my car, and in order not to delay the sale process for a long time, I did not bother with determining the price for which I would sell it. I walked through the car market, found out how similar car models were sold, after which I subtracted from the “maximum” the cost of eliminating the main, clearly noticeable shortcomings, and in less than an hour the car was sold. One of the shortcomings was the presence of a small dent on the left front fender, small scratches on the hood. I later learned that the buyer was a professional bodybuilder. He eliminated the “body” flaws and exactly one week later he sold my former car, earning an additional thousand overseas rubles. When I asked him what he did with the wing, he replied that he did not fool around, but applied a half-centimeter layer of putty. As you know, a thick layer of putty tends to dry out and fly off. Subsequently, his buyers clearly "flyed a pretty penny."
To avoid such troubles that enterprising car dealers can arrange for you when you need to buy an “iron horse”, this article is intended.
The described device is relevant when, when examining the state of the car body, it often becomes necessary to measure the thickness of the paintwork. The device allows you to control the thickness of the paint coating applied to any ferrous metal products.
When measuring the coating thickness, the device is applied to the controlled surface, the button is pressed, slightly shaking and turning the device, the maximum deviation of the arrow is achieved and the thickness value is read. The thickness of the coating of car bodies with ordinary paint is in the range of 0.15 ... 0.3 mm, and with metallic paint - from 0.25 to 0.35 mm. If the thickness is greater, then be careful when buying such a car, unintentional costs may appear.
The paint coating thickness gauge is built according to a simple scheme, provides acceptable measurement accuracy, and most importantly, its compactness and “mobility” allow it to be used in the automotive market when choosing a car.
Schematic diagram of the coating thickness gauge is shown in the figure below.
The basis of the scheme is taken from one of the popular magazines. The author of the device is Yu.Pushkarev. When studying his scheme, I did not find any technical flaws at first, but after assembling and checking, I once again understood why a novice radio amateur loses the desire to become a radio amateur. I eliminated the shortcomings in the circuit, after which the device really worked as it should.
The device is powered by a Krona battery, the current consumption does not exceed 35 mA, the device remains operational when the battery voltage drops to 7 V. The operating temperature range is from +10 to +30 C. The device is assembled in a plastic box with dimensions of 120x40x30 mm.
The master oscillator assembled on the DD1 timer (see the diagram in Fig. 1) generates rectangular pulses with a frequency of 300 Hz and a duty cycle of 2. The R3C2 integrating circuit converts the rectangular pulses into a sinusoid, which improves the measurement accuracy. The signal level regulator - trimmer resistor R5 - sets the optimal mode of the measuring transformer T1. The amplitude of the signal at the output of the UZCH DA1 is approximately 0.5 V.
The W-shaped plates of the measuring transformer are butted together, but without a package of end plates. The role of the magnetic contact here is played by the metal base, on which the studied paint and varnish coating is applied. The thicker it is, the larger the non-magnetic gap in the magnetic circuit of the measuring transformer. A larger gap corresponds to a smaller connection between the windings, therefore, a lower voltage on the secondary winding of the transformer. The R6C4 circuit is an additional filter that eliminates the high-frequency components of the signal. Capacitors C5 and C7 are separating.
The microammeter RA1 shows the current of the secondary winding of the transformer rectified by the diode VD1. The voltage regulator DA2 allows you to maintain the stability of the gain UZCH DA1 when changing the degree of discharge of the battery GB1. Resistor R8 and push button switch SB2 allow you to periodically check the battery voltage. The measurement is carried out with the button SB1 pressed.
The VT1R9R10R11 transistor stage is designed to supply an initial bias - to create a threshold that turns off the VD1 diode. Thanks to him, the arrow of the microammeter deviates only if there is a magnetic contactor in the field of the measuring transformer. This is necessary to set the maximum measurable thickness and increase the measurement accuracy. With the specified resistor values, the limits of the measured thickness are from 0 to 2.5 mm. Measurement accuracy with a thickness of 0 to 1.0 mm - ± 0.05 mm, and from 1.0 to 2.5 mm - ± 0.25 mm. To reduce the measurement limits from 0 to 0.8 mm, and therefore increase the measurement accuracy, the resistor R10 is increased to 3.9 kOhm. This allows you to raise the triggering threshold of the diode VD1, and "stretches" the scale.
The details of the device are placed on a printed circuit board (Fig.), made of fiberglass 1 mm thick foil-coated on one side. The transistor cascade VT1R9R10R11 was initially absent and appeared only in the course of refinement. There was no place on the board for it, so the cascade was assembled by surface mounting.
All fixed resistors are MLT-0.125, tuning resistors are SPZ-276. Capacitors C1, C2, C4 - KM-6 (or K10-17, K10-23), capacitors C3, C5, C6 - K50-35. The PA1 microammeter is the recording level indicator from the Elektronika-321 tape recorder (frame resistance 530 Ohm, full deflection current of the arrow - 160 μA).
Transformer T1 is wound on a magnetic circuit Ш5Х6 (an output or matching transformer from pocket receivers was used), the primary winding contains 200 turns of PEL 0.15 wire, the secondary - 450 turns of the same wire. Only W-shaped plates are required. During assembly, they are lubricated with epoxy glue, after the glue has dried, the ends of the package are leveled with a velvet file. The transformer is glued from the inside into a rectangular hole in the device box so that the working ends of the magnetic circuit protrude 1 ... 3 mm beyond the box.
The timer KR1006VI1 can be replaced by LM555, and the stabilizer KR1157EN502A can be replaced by 78L05, KR142EN5A (L7805V). It is better to use 78S05, which is manufactured in a small package, has a lower output power, but you don’t need a large one. As a differential amplifier DA1, a KIA LM386-1 chip is used.
To establish the device, set the slider of the resistor R7 to the middle position. The transformer with the working end of the magnetic circuit is applied to a flat, clean surface of a steel sheet and the resistor R5 switches the arrow to the final division of the RA1 microammeter scale. After that, laying sheets of paper 0.1 mm thick (density 80 g/m2) between the transformer and the metal surface, calibrate the device. This is an ordinary "office" A4 paper, sold in standard packs and not used anywhere. To calibrate the device, its case is carefully disassembled, a graph paper is placed under the arrow, on which the readings are marked during the calibration. After that, a scale is drawn in a graphic editor, which is printed on a color printer and glued inside the device, after which the device is assembled.
Resistor R8 is selected so that with a fresh battery, when you press both buttons SB1 and SB2, the microammeter needle deviates to the final division of the scale. Having connected a battery discharged to 7 V to the device, repeat the measurement on the scale of the microammeter and make a mark corresponding to the discharged battery. It is possible in another way - connect in series "Krone" an ordinary finger-type battery, changing the polarity to the opposite. To the difference in readings with and without a finger battery, add another quarter, this will be the limit value of the discharge. Be sure to display this value on the scale. I divided the rate from the discharged state in two colors - green and red section of the scale.
P.S. : When using the device in low ambient temperature conditions, it is advisable to keep it in the inner pocket of your clothing, taking it out just before the measurement.
In my meter, for lack of a smaller one, I used a transformer with a Ш8Х8 core, and an increase in the mass of the magnetic circuit necessitated a decrease in the generator frequency. To do this, I increased the value of C1 to 47 nF. The device showed excellent performance.
Do not use metal alloy materials to calibrate the instrument. At first I used the plane of the caliper, and although it is iron, it contains impurities of non-magnetic metals, to which the device does not react at all.
When assessing the technical condition of a used car, the first thing they pay attention to is the body, whether there are any defects on it. In addition to the obvious damage visible to the naked eye, there are others hidden from the inattentive gaze. To say for sure whether a used car has hidden defects, you need to know the exact thickness of the paintwork: if you had to deal with second-hand car dealers, then you might notice that they carry a special device with which, within two to three minutes can determine whether the car was involved in an accident or not.
In some cases, a thickness gauge can save you a lot of money.
This device is the paintwork thickness gauge. In skillful hands, such a device helps to find out a lot of useful information about the past of a used car.
Types of thickness gauges
Today, there are several types of this device on the market with a variety of operating principles, but the most common among motorists are ultrasonic, magnetic, electromagnetic and eddy current thickness gauges. Their price and capabilities, of course, differ from each other, so we will consider each type and its specialization separately.
Ultrasonic Thickness Gauge
- Ultrasonic thickness gauges. They are a universal solution for checking paintwork with a thickness gauge: such a paint thickness gauge works equally well not only on metal surfaces, but also on composite materials, ceramics and plastics, which gives ample opportunities for use: you can qualitatively check the paintwork with an ultrasonic thickness gauge not only on the body , but also on the decorative part of the car, such as a plastic bumper or a carbon insert.
The only downside is the price. The cost of the simplest ultrasonic thickness gauge for car paintwork starts at 10,000 rubles. However, such a device is considered professional, not focused on the average buyer, so this drawback, one might say, is far-fetched.
The simplest and most inaccurate magnetic thickness gauge
- Magnetic thickness gauges. They work according to the following principle: the device contains a magnet connected to an arrow pointer. You just have to attach the thickness gauge to the car body: the thinner the paint layer on the car, the stronger the attraction of the magnet to the body, the arrow will deviate more. Accordingly, the smaller the angle of inclination of the arrow, the thicker the level of coating on the body, which should alert you. The advantages of thickness gauges with a magnet include ease of operation, no need for batteries and a low price - the cheapest such unit costs about 450 rubles. However, such thickness gauges also have disadvantages. The most serious: low accuracy of readings. These devices show more or less correct results if the coating layer does not exceed 1.5 millimeters.
- Electromagnetic thickness gauges LKP. They are considered the most reliable and practical devices, since they give the most accurate results, and the cost does not exceed 3000 rubles. Alas, there are also disadvantages. Checking the paintwork with an electromagnetic thickness gauge makes sense only on surfaces with an impurity of iron. Such an aggregate, as they say, will not pull plastics and non-ferrous metals - remember this at the time of purchase.
Eddy current thickness gauge Et 11S
- Eddy current thickness gauges. Its “trick” is the ability to estimate the thickness of the applied coating on any metals, besides, it gives the most accurate measurement results. The disadvantages of such devices include the dependence of measurements on the electrical conductivity of the metal whose coating thickness you are measuring. That is, when working with copper, aluminum and other metals with good current conductivity, the measurement results will always be accurate. But using a paint thickness gauge on, for example, iron, errors will appear in the measurements, sometimes very serious ones. An eddy current automobile thickness gauge costs around 5,500 rubles.
How to properly use and calibrate the instrument
It is necessary to use the thickness gauge wisely, otherwise it simply does not make sense. Here are a few simple tips for those who want to use a thickness gauge productively to check the thickness of a car's paint.
Buy smart. The cheaper the thickness gauge, the less its functionality: the cheapest measurement solution will help you understand whether the car was puttied or not, but there will be problems with determining an additional layer of paint. In addition, not all surfaces can be measured. To work with aluminum, you need to purchase a more expensive device, and for plastic, you will have to fork out for an ultrasonic thickness gauge, the price of which can be no less than a cheap used car.
In order not to waste money, buy a car thickness gauge with a knowledgeable person, or contact a sales assistant: explain the situation to him, and he will tell you which unit is right for you.
If your friends have a thickness gauge that suits you, just ask for it for a while. By the way, some car companies have a service for renting a paint thickness gauge. Instead of buying, you can rent a device for a small price while buying a used car.
Calibration
Video: Setting up and calibrating the thickness gauge model CHY 115
The first thing to do after purchase is to calibrate. Of course, in production, thickness gauges are calibrated, but a new unit needs to be checked. Calibrate when temperature fluctuates or when batteries are changed.
In order to calibrate the paint thickness gauge, reference plates made of plastic or steel are used, on which a layer of paint of a certain thickness is applied. If, for example, the device works with steel and aluminum, then the kit will include steel and aluminum plates for calibration. Also included is a calibration film on which measurements are made.
Calibration process:
Calibration plates with film
- Place the thickness gauge on the desired plate and reset the values displayed by the gauge.
- Next, put the device on the calibration film and wait until the device gives out data
- Numbers are printed on the calibration film. The same indication should be on the dial of the thickness gauge.
If the readings are different, readjust your machine so that the readings on the film and on the instrument match. If you neglect calibration, it may backfire on you in the future.
Adjust the thickness gauge for each specific case separately. Today, most thickness gauges have a range change function - always use this function as it greatly reduces the possibility of incorrect measurement.
How to check a car with a thickness gauge
Use the thickness gauge correctly. This is important because the result of your measurements depends on it. For measurements, use the following algorithm:
Body paint thickness chart for various car brands
Before working with a thickness gauge and measuring the thickness of the paint, it is necessary to clean the car. On a dirty body, the readings of the device will be inaccurate.
Using a thickness gauge, apply it to each part of the body, starting with the front wing (any), then moving along the entire body. Measurements on each part of the body (hood, roof, door, fender, etc.) are carried out at 3-5 points, preferably at the edges and in the center. The device is applied perpendicular to the body part, if at an angle, then the readings of the device will be inaccurate.
Be sure to check the paintwork inside the body - in the cabin. Open the door and measure the thickness of the paint on the racks, measure the paintwork of the frame, where there will be access.
After taking all the measurements, calculate the arithmetic mean for each part, compare the obtained values \u200b\u200bwith each other. Take several measurements in a row to get the most accurate result. There is always an error, so never trust the numbers obtained after one measurement - it is better to take several measurements and calculate the arithmetic mean, this guarantees the maximum reliability of the data.
Video 1: How to measure paint thickness with a thickness gauge
Pay attention to thick sections of bodywork. When measuring, keep in mind that the places of the body with a new painting differ in thickness from the places where there is a layer with only factory paint. Most often, the repainted places are 2-3 times thicker. If, when taking measurements, you find a section that is 100-150 microns thicker than the rest of the body, then you can be sure that it was repainted. If the thickness exceeds 160 microns, then there is a possibility that this place on the car body was also puttied.
There are also reverse situations: for example, the average thickness of the paintwork is 110 microns, and in some place it is less, about 80-90 microns. Why? Apparently in this place the body was polished using polish, which contains abrasive materials - during such polishing a small layer of coating is removed.
Video 2: How to measure paint thickness with a thickness gauge
When measuring, pay due attention to the sealant and the gaps between the body elements. A layer of sealant is applied at the welding points of the body components, on the doors, the rear panel of the car, inside the hood. If you find that there is no sealant, or it is applied unevenly, and the bolts are not covered with paint, or there are chips, then this means that the part was removed for repair or replaced with a new one. Some used car dealers don't wash the car on purpose so you can't check the condition of the sealant. So if the seller doesn't want to take the car to the car wash, he may be afraid that you will find a lot of chips.
Look at the gaps of the car doors, trunk, hood when they are closed: if they are different, or the opening elements cling to the body, then they may have been replaced, or an additional layer of paint has been applied.
Use a paint thickness gauge to determine where "crossovers" are located on the vehicle. These are places where coating layers merge from various car body parts; these places cannot be found without special devices. Transitions are found in those places of the body where it is impossible to unscrew the parts.
An amateur is not a professional. Of course, finding out the past of the car by the thickness of the coating is the easiest way, but it will not always help. Auto repair shops also have not the most stupid people who know the thickness of the factory body paint perfectly and will adjust the new coating layer to the range used by the manufacturer of a particular car model.
In addition, in some cases, a different thickness of the coating on the body is normal. Car parts are painted individually, or using different painting technologies, which, of course, affects the thickness of the paintwork. The error of factory painting ranges from 10 microns to 35 microns, while it is necessary to take into account the possible error in measurements of an automobile thickness gauge (2-4 percent).
As you can see, there are a lot of subtleties, so do not hesitate to turn to an experienced person who can literally determine by eye whether they are deceiving you or not.
What should measurements show?
As a rule, on modern cars, the thickness of the paintwork does not exceed 200 microns.
- Therefore, if a measurement with a thickness gauge shows 200 - 300 microns of paint, then this indicates a slight re-painting, for example, a scratch has been painted over. This does not affect the technical characteristics of the car in any way, but it gives a reason to bargain.
- If the values are from 300 to 1000 microns, then there is putty under the paint, and this is a risk that over time it will crack and fall off along with the paint.
- If the numbers on the thickness gauge show more than 1000 microns, then the car was in a major accident and it is better to refrain from buying.
- The maximum that the device can show is 2000 microns, which indicates that the putty layer is very thick.
Video: How to choose and what is inside the thickness gauge.
Is the thickness gauge worth the money?
Yes, it’s worth it: the paintwork thickness gauge can fully pay off during the first purchase of a car: for example, if you find body defects, you can drop $ 150-300 from the price of the car, depending on the situation and the pliability of the seller.
All information in the article is purely promotional in nature, since technology does not stand still, cars are painted using the latest developments, so first of all, consult with specialists.
