Coating thickness measurement is an essential activity for many industries, which rely on the quality of their coatings and paintings.
These industries normally use coating thickness measurement as an accurate technique to verify that coatings applied on their products comply with their standards.
What is Coating Thickness Measurement?
As the name suggests, coating thickness measurement is a non-destructive testing method to measure the thickness of a coating applied on the surface of a product.
Apart from keeping the integrity of the part, an interesting aspect of this non-destructive measuring method is that it can be applied on both dry and wet coatings. The main difference between dry and wet coating thickness measurement will be the type of instrument employed.
Why is coating thickness measurement essential in many industries?
The fact that coating thickness measurement can be performed on both dry and wet coatings makes it a great solution for different industries and at different points of their production processes.
For example, quality control (QC) and maintenance departments can benefit from dry coating measurement tools to carry out inspections of dry insulating layers applied on metal substrate, such as paint and plastic layers.
These inspections are commonly performed to identify:
- Loss of coating layer that may result in corrosion.
- Incorrect coating thickness that may lead to premature failure of the coating.
- Coating thickness matches design requirements.
- Coating coming from suppliers matches order requirements (incoming goods inspection).
Timely detecting any problem on the coating can result in an increased lifespan of the coated part and a very significant reduction of costs in the long term.
Moreover, having the appropriate coating thickness allows achieving the desired balance between aesthetics and protection of the coated part. Thick coatings that are not even may result in undesired textures and the possibility of paint cracking leading to failure.
How to measure coating thickness?
As described before, there are two forms of measuring coating thickness: dry coating thickness measurement and wet coating thickness measurement.
Dry measurement is usually applied to measure any insulating layer applied on a metal substrate, such as paint and plastic layers. It is carried out by means of coating thickness gauges, such as our high accuracy digital coating thickness gauges which are capable of detecting insulating (enamel/paint etc.) and non-ferromagnetic (aluminum/zinc etc.) coatings over ferromagnetic substrates and insulating (enamel/ paint etc.) coatings over non-ferromagnetic substrates.
Coating thickness gauges use the magnetic induction measuring principle for ferrous base coatings and the eddy current measuring principle for non-ferrous base coatings. In addition to paint thicknesses measurement, these instruments can measure different types of coatings applied to sub-layers or resulting from galvanic baths such as anodizing, chrome plating, galvanizing, etc.
On the other hand, wet measurement is usually applied as part of the painting or coating application process, since it does not require the coating and varnish layer to be completely dry. This is especially useful for coating service providers, as it allows them to adjust immediately the coating layer as necessary without the need of post processing.
What are the applications of coating thickness measurement?
As mentioned above, coating thickness measurement is essential for many industries.
Some of the sectors that commonly perform coating thickness measurement include, but are not limited to:
- Marine sector.
- Commercial vessels.
- Mega yachts sector.
- Oil & Gas.
Common activities in these sectors that require coating thickness measurement are:
Piping inspections in the oil and gas, and the chemicals sectors to avoid corrosion issues that may result in pipe failure, costly shutdowns and industrial accidents.
Checking the paint coating consistency on an aircraft or component in the aerospace industry for improved safety and performance.
Nautical and maritime maintenance, like in the case of bulkheads, tanks, ship hulls, and other coated components.
Verifying the integrity of pressurized containers such as fire extinguishers, gas tanks, industrial boilers and others that depend on coatings for corrosion protection.
Maintenance inspections on bridges, especially those with metal structures, which are coated to withstand the hardest environmental conditions.
How to select a coating thickness measurement instrument?
Selecting the right coating thickness measuring instrument for your specific application is very important, since making a wrong selection may result in a total inability to obtain any value or obtaining false information.
Any of the aspects mentioned above means undesired consequences such as increased costs, customer dissatisfaction and loss of reputation.
To avoid all those problems, some aspects must be considered to select the right coating thickness measurement for your application:
- The coating type, whether it is dry or wet.
- The type of coating and material coated.
- The roughness of the coating. This also affects the type of probe to be used.
- The area measured and its location.
- The geometry of the part under test.
At this point, it is also important to highlight that there are destructive methods to measure coating thickness. For example, our paint inspection gauge (P.I.G.) – SAPIG548 provides high accuracy measurements in the range of 2-2800µm on every substrate, like steel, non-ferrous metal, plastics, wood, concrete, plaster, among others with the aid of a built-in microscope allows you to measure the thickness of each layer. This instrument, thanks to its microscope, allows measuring both the total thickness of the coating and each single layer deposited on the substrate.
However, the integrity of the part is not kept, as this is a destructive test.
The fact is that, no matter your application, we have a coating thickness measuring instrument to cover your needs.
If you want to check the dry and wet coating thickness measuring instruments we offer to select the one for your application, just click here.
Of course, if you are not sure yet or have any doubts about measuring coating thickness, our recommendation is to contact us and one of our experts will gladly help you.