The monitoring of climatic conditions such as temperature, relative humidity, dewpoint and moisture in industry is often vital to the success of the application of a coating. These parameters determine both the conditions for the application of the coating, and the resulting quality and performance of the coated product.
In the protective coatings industry, moisture can form on the surface when the surface temperature is low enough to cause condensation from the atmosphere. The dewpoint temperature (Td) is the point at which this occurs.
Monitoring the surface tempearte (Ts) realtive to the air temperature (Ta) and its relative humidity (%RH) allows the dewpoint temperature to be calculated and compared to the surface temperature. This difference in temperature (TΔ) is the key parameter dictating when it is safe to apply the coating.
The temperature of the coating material is also important as temperature affects the coating′s shelf life, viscosity and its application characteristics.
The continuous monitoring of the climatic conditions during the cure process (drying) is also required. If the temperature is too high, the coating can dry too quickly, leading to surface defects. If the temperature is too low, the cure time is extended, leading to delays in applying a further coat, other types of surface defects may affect the further coat, such as amine blush.
The cure process for powder coating requires a specific temperature to be achieved for a specific period. Monitoring the oven profile allows the user to ensure that the product is brought to the appropriate temperature and held at that temperature for the specified time. If the oven or product is too hot, the coating can burn, if it is too cold, the coating does not cure, leading to poor adhesion and appearance.
The presence of moisture within a material will result in poor adhesion, premature coating failure and poor appearance. For example, applying a powder coating to a damp wooden panel will cause steam to be created when the panel passes through the curing oven, thus causing damage to the coating.
Elcometer offer a complete range of dewpoint and relative humidity meters, thermometers, digital thermometers, hygrometers, dataloggers, moisture meters and anemometers to monitor climatic conditions.
Digital Coating Thickness Gauges (Dry Film Thickness Gauge)Digital coating thickness gauges (also known as paint meters) are the most widely used due to their high level of accuracy and they can be used to measure the coating thickness on almost any substrate, whether ferrous or non-ferrous.
Elcometer offer a range of digital coating thickness gauges from the new Elcometer 456 – available with either integral or separate probes, the Elcometer 415 Paint and Powder Thickness Gauge, to the Elcometer 311 Automotive Refinishing Gauge.
A clean surface is key for the successful performance of a coating.
During the initial surface preparation, in addition to brushing or grinding, a coated surface can be blasted, high pressure water-jetted or simply washed down. In many cases, the abrasive media or water is recycled. In these instances, it is important that the level of contaminants in the recycled material is carefully monitored to avoid the re-contamination of the surface being cleaned.
Surface Profile Gauge
Surface Profile Gauges are used to measure the profile height of a surface. The degree of the surface profile on the surface affects a coating’s overall performance and determines aspects such as adhesion, coverage and overall volume of coatings used. If the surface profile is too large the amount of coating required increases, otherwise there is a danger that the peaks remain uncoated – allowing rust spots to occur. If the surface profile is too small there may be insufficient key for adequate adhesion leading to premature coating failure.
To ensure the correct surface preparation optimises the performance of the coating and material usage, the profile height of a surface needs to be accurately assessed and measured. It is essential to know this parameter as it determines the adhesion, coverage and overall volume of coating used.
Elcometer offer a wide range of digital and mechanical Surface Profile Gages, Surface Roughness Testers, Surface Comparators and Testex Tapes, for surface profile testing or for surface roughness testing. A Surface Profile Gage helps to record and access the value from the top of the peak to the bottom of the valley measuring the profile height of a surface. A Surface Roughness Tester records and measures the roughness over a specified distance, recording peak-to-valley average. A Surface Comparator is used as a very quick guide to compare freshly blasted profiles to pre-defined profiles. The standard Surface Comparators are available as either grit, shot or sand. A Surface Profile Replica Tape (Testex Tape) is used to compress against a roughened material to replicate details of its surface roughness and is then used with a Thickness Gauge to measure the peak-to-valley height of a surface profile.
Wet Film & Powder Thickness
Measuring coatings before they have cured can predict the final film thickness.
Applying too much coating not only wastes time and materials, it can also affect the performance and finish of the product. Too much wet film can cause the coating to crack as it cures; too little coating increases the risk that the substrate will not be sufficiently protected, leading to rust spots.
In the powder coating industry, ensuring the end product has the correct levels of adhesion and appearance is dependent on the thickness of the powder prior to the curing process. Too much powder can lead to poor adhesion, too little can lead to a discolouration and loss in gloss of the coating.
Wet Film Combs
Wide selection of wet film combs from long edge combs to hexagonal combs through to punched aluminium combs.