What is paint decontamination? Paint decontamination is any method that removes contaminants…
Paint meter – what is it and how to use it?
Paint thickness gauge – what functions should it have and how to use it?
A paint thickness gauge will allow us to check the condition of the car's bodywork before purchasing. How to use it and how to choose a good device? We give you a hint!
How does a paint thickness gauge work?
The condition of the bodywork is one of the most important issues that we should verify before choosing a used car. Thanks to the paint thickness gauge, we will find out whether the car has been repaired.
Of course, there is nothing wrong with removing parking dents or scratches. However, an appropriate device will allow us to check whether the seller's assurances regarding the condition of the car match the actual condition of the vehicle.
How does a paint tester work? This type of equipment uses magnetic induction or eddy current methods. The sensor checks the thickness of the non-metallic layer placed on a metal substrate. In other words, it detects the distance between the measuring probe and the "bare sheet metal". If we were to use the analogy of furniture, the meter would show how thick the layer of paint is on the wood.
The non-metallic layer may consist of paint or a protective coating, but also filler if the bodywork has been repaired. The paint thickness gauge gives results in micrometers (one millionth of a meter, symbol μm).
What types of paint thickness gauges are there?
Paint thickness gauges can be divided into three main types based on differences in design. The devices can be equipped with a flat, pressure or ball probe.
A flat probe is a basic sensor that is installed in cheap paint thickness meters. It must be pressed precisely against the surface to be checked to obtain the result. A more advanced solution is a paint tester with a pressure probe. It ends with a sensor that hides in the housing when pressed against the bodywork.
The third type is a paint tester with a ball probe. It provides the most accurate measurement results. It can be used to check the coating thickness on convex and concave surfaces, and not only on flat surfaces, as is the case with less advanced probes.
What functions should a paint thickness gauge have? What is the difference between a cheap meter and an expensive one?
A basic paint thickness gauge will probably have a flat probe attached directly to the device. Such equipment may be sufficient in many situations, but it will not offer very accurate results. It is possible that it will have a resolution that will allow you to check the paint thickness with an accuracy of 10 μm. In addition, a cheap meter will be suitable for testing bodies made of steel and galvanized steel, but not necessarily aluminum bodies.
What features should a good and more expensive tester have? Which paint meter should I choose? If we want the best results, we should choose a thickness gauge that also detects aluminum.
In addition, the tester should have good resolution and show results with an accuracy of 1 μm. An important feature is the probe. As we mentioned, the best one is the ball one. Not only the type of sensor is important, but also its mounting method.
A survey is the right solution
The recommended variant is the probe on the cable. Due to the fact that it is not attached directly to the meter body, we can reach the nooks and crannies with it, for example the inner wheel arches or the engine compartment. Besides, the paint thickness gauge with wired probe ensures more accurate measurement. We hold the device with the display in one hand and the sensor in the other. You won't have to exercise to check the result, a trembling hand will not distort the result, as may be the case with testers with an integrated probe.
What other features of the paint meter should you pay attention to? It is worth checking in what temperature range a given device operates, whether it can be used to make reliable measurements both when temperatures exceed 20 degrees Celsius and when there is frost.
A useful option is to remember measurement results. More advanced models have the ability to export data to a file or application smartphone. Features that make measurement easier include: large, backlit screen, built-in flashlight and sound prompt system.
Paint thickness gauge
How to properly check the paint thickness with a meter?
Before we start checking the bodywork with a meter, it is good to know what results we should expect. The typical thickness of the paint coating is from 70 to 170-180 μm. It is worth noting that there may be differences depending on the country of production or vehicle brand. Models from Japan or South Korea often have a thinner coating compared to European cars, and a result of 100 μm will not be unusual.
Not all body elements need to be uniformly thickly painted. However, fluctuations should not exceed 40%. However, if they are larger, it may be a sign that the part has been painted, especially if the meter shows a result exceeding 200-300 μm or the elements on opposite sides of the vehicle differ in terms of the result (for example, the left fender has a paint thickness of 120 μm and right 250 μm).
Ways to use a paint thickness gauge
How to use a paint thickness gauge? It will be best if the car is clean. While a ball probe tester can handle dirt, a basic meter may show false results. Proper preparation of the vehicle for sensor testing is described in the text How to decontaminate car paint?.
Place the probe perpendicularly on the body and press lightly. The order in which items are checked does not matter much. The point is to examine the entire body. We can start with the roof, because it is an element that is relatively rarely painted.
Then we use the gauge on the selected side, from the front fender, through the front and rear doors, to the rear fender. Then we go to the other side of the vehicle. Remember to check the paint on the pillars, trunk lid and hood, as well as in the recesses after opening the doors (thresholds, pillars, etc.)
Importantly, we check a given element in several or even a dozen places. For example, we examine the door not only in the middle, but also on the pillar, upper and lower edges, and in the front and rear parts. During the repair, the painter could use such a shading technique that the difference in color was as small as possible. A given fragment may have a different thickness compared to the rest of the door, fender or hood. We describe the entire process in the article How to measure the thickness of car paint?.
Should I buy a meter or hire a specialist to measure the thickness of the paint?
Even a basic paint thickness sensor can give us an answer about the condition of the car. Operating the device is simple and does not require the help of a specialist.
Nevertheless, if in doubt, take the car to a specialist who will help assess the condition of the bodywork. It is possible that entire elements in the car have been replaced to match the color. It will be a good idea to check whether the windows have the same production date and whether there are any signs of disassembly of components. We write in the text what to pay attention to when choosing a second-hand car We buy a used car.
