The popularity of electrically conductive coatings for plastic enclosure electromagnetic shielding is growing day by day. The layer of coating makes the plastic conductive. The process of conductive painting includes spraying a layer of paint that is conductive. The paint is made conductive by filling it with metals that are conductive in nature, e.g., nickel, copper, or silver.
Remember, the conductive paints cannot be applied or handled in the same way as conventional paints. The one who paints the plastic must be ready for the task as it requires proper knowledge to use conductive paints. Otherwise, the results can be disastrous. Spraying electrically conductive paints is art and demands personnel training, experience, proper up-front part design, equipment modifications, and practice.
To help amateurs, we are here with this article containing tips to spray electrically conductive paints.
- Using electrically conductive paints – As conductive paints are infused with heavy metals, metal particles settle to the bottom of the paint quickly. Even if you are using the paint of high quality to prevent this from happening, the conductive metal will still fall out of suspension. But it is very crucial to avoid this settling when the paint is being applied. So, to prevent this, it is suggested to keep the paint continually moving. It can be done by using an air-driven mixer for the paint pot or a recirculation loop. If in case, the hand-held spray gun is being used, then keep on shaking the spray cup between each pass constantly.
- Storing electrically conductive paints – When you are going to use the paint that has been stored, it requires special attention. It is so because particles not only settle at the bottom but also hard-pack with time. Shake the container vigorously for several minutes to ensure that the metal is mixed in the paint thoroughly. It is recommended to scrape the bottom of the container with a clean spatula.
- Equipment for painting – To make sure that the paint is sprayed perfectly, it is crucial to use compatible equipment. It will prevent your energy from continuously stirring the paint. There are many air-atomized spray guns and hand-held equipment available that can be used for uniform application of conductive paints. The gravity-feed spray gun, the siphon-feed spray gun, and low-pressure spray gun are some of the guns used by manufacturers for applying electrically conductive paint.
- Thickness of the layer of the paint – Many people believe that the shielding effectiveness increases as the paint’s coating is increased. But it is not so. Thicker will be the coating; lesser will be the shielding.
To achieve a good level of EMI shielding, keep the thickness of the paint uniform. While painting, keep it in mind that issues can arise with different products because of their design.