How to check the quality of the powder coating?

The key to a quality powder coating is good equipment, well-established work of painters and, of course, the quality of the paint itself. And you need to control absolutely everything constantly. Even if your supplier has been working with you for a long time and everything has been always good – you still need to check the new batch.

It is also necessary to control the serviceability of the equipment, the accuracy of compliance with the technology of powder coating, compliance with the conditions of storage of paint. We also advise you to constantly train staff so that your painters knew the intricacies of working with powder paints.

In this article we will tell about methods of checking powder covering on its conformity to necessary properties. Of course, some characteristics can be checked “by eye”, such as appearance, shine and color, comparing your product with the reference sample. But if you need a reference accuracy of these indicators, it is better to use the appropriate devices.

Powder coating properties and test methods

Coating properties	How to check?
Resistance to atmospheric influences	It is checked under atmospheric influence. It can be “natural” – we take the product out of the room and wait. Or accelerated – under the action of catalysts.
Resistance to rust	The painted product is placed in a salt fog, if there are no changes, the indicator is normal.
Resistance to chemical exposure	Checked by immersion in a chemically active environment.
Electrical insulating properties	Electrical resistance is measured by ohmmeters or megohmmeters.
Heat resistance	The product is heated to high temperatures.
Abrasion resistance	It is checked by the Taber device. The painted product is fixed on a special disk under abrasive circles. The required load is set, the wheels move actively, pressing on the coating and creating certain degree of damage.
Impact resistance	It is checked with a Gardner device. This is a glass tube 1 m long and with an inner diameter of up to 30 mm. The painted product is placed under the tube at an angle of 45°. A jet of quartz sand is fed from the tube. The indicator is measured by the amount of sand used to remove the coating
Scratch resistance	Use the pencil method to check. On a covering move a pencil at an angle of 45°, gradually increase pressure on a product. Pencils of different hardness from 6B to 8N are used.виріб.
Smoothness, texture, wrinkles, metallic, streaks, marks, transparency, divorces, color	All these parameters are checked visually by the painter. The painted product is compared with the reference sample. It is important to make a visual assessment in daylight, at the same angle. In laboratories, these indicators are checked in a special cabinet equipped with 5 main light sources.
Shine	It is measured by a special device – a light meter. A beam of constant light is directed at the product at a certain angle and the amount of reflected light is measured. As a rule, gloss is not measured on textured and rough surfaces.
Opacity	Measured using the contrast ratio. The paint is applied in layers until the boundary between the black and white areas of the surface completely disappears. Or you can use a spectrophotometer.
Degree of approval	The coating is wiped with a solvent.
Resistance to overexposure	It is measured visually under the influence of temperature.
Adhesion	It is measured by an adhesiometer and by the method of lattice cuts.
The particle size of the powder	It is checked by sieve analysis. The powder is passed through sieves with cells of different sizes.
Covering the edges	Under the magnifying glass, the edges of the product are inspected.
Formation	Bend test. Flexibility is checked by bending the coated plate around the conical mandrel.
Check for the inscription	An inscription is applied to the painted product and it is checked how well it adheres to the surface.

If the paint meets all the properties, it is really high quality, and the coating created by it will last a long time and will not change over time (of course, if you follow the technology).