Powder coating is an easy process that does not take much time and does not require huge labor costs. However, in order for everything to work properly and the coating to be of high quality, it is necessary to comply with the technology of applying the powder. Errors in handling powder equipment can lead to significant powder coating defects.
One of them is powder paint sapping or reverse ionization. This is a problem that many powder coating painters face. Because of what this problem arises and how to solve it, we analyze in this article.
Causes of sapping
Powder paint may crumble, firstly, due to insufficient or too much charge on the electrode. Due to problems with the charge, all the powder crumbles and just flies into the recuperator. Particularly relevant is the problem of overcharging of paint particles when spraying “metallic” or “antique”.
Secondly, the problem of sapping may be poor grounding of the product or equipment. An earthing contact may be disconnected inside the spray gun.
The next reason for sapping is the insufficient preparation of the metal for painting.
This problem may also occur if the spray gun is clogged with powder inside.
If, on the one hand, the metal is painted with a tribostatic gun, and on the other with an electrostatic gun, then on the side that was painted the paint will fall off first.
How to fix the problem
The first thing to do to fix the problem is to check the grounding. Perhaps it is better to ground the product on which the powder is applied. Grounding should be continuous, not temporary. It is also necessary to check the equipment grounding. Especially the spray gun.
You also need to monitor the coating layer and its uniformity. That the paint did not crumble and lay flat, check the charge that the spray gun emits. Adjust it if necessary. It is very important to charge the gun when working with powders with effects.
Check for powder clogging inside the gun. Clean it so that nothing interferes with the paint.
Make sure that the preparation of the metal for painting is done according to the technological requirements. The product must be cleaned by sandblasting, dirt, oils and fats should be removed from it. Before painting, metal must be degreased. If necessary, phosphate or chromate. After cleaning, the product must be thoroughly washed and dried. Only on a completely dry surface can powder be applied.
Paint one product with one gun.
In order to be sure of the correct operation of all equipment, it is necessary to conduct a regular audit of production. At least several times a year. Specialists will be able to check the operation of absolutely all devices and tell you if something goes wrong.