How to paint with a spray gun correctly
The spray gun is an irreplaceable tool for powder painting. It is made for coating the product.
Without knowing the rules for its use, the paint will coat the product, too poorly.
In this article, we will tell you what you need to know for a safe and high-quality powder coating of a material.
Which gun to choose
The sprayer operational principle is paint particles electrification, due to the electric field, falling on the material and fixed on it.
Particles can be electrified by friction or an external source. This is what led to the presence of two types of spray guns: tribo and corona type.
The corona gun requires a generator that supplies high voltage to the corona electrode.
The tribostatic powder spray gun charges particles by friction. It does not require any additional equipment.
The crown-type gun can produce 20 kilograms of paint per hour, and the tribo only 12. The first one can work with any powder paint and for the second one the paint quality is very important. For tribo, mainly combined powders are used.
The tribostatic gun makes it possible to coat complex parts and ensures high quality and uniformity of color. But the work of these tools is very dependent on the humidity in the room where the processing takes place.
How to paint with a gun
Right after paint applying to the surface, it must be carefully prepared: cleaned and degreased.
After that, the product must be suspended in the spraying chamber. The camera must be grounded.
After that, prepare the gun.
If you are using a corona tool, then:
- Connect the connection and the compressed air line with a hose.
- Set the air pressure, depending on the size of the product, 0.1-1.0 atm.
- Plug the power adapter into a power outlet.
- Ground the thin wire in a single circuit with the part to be painted. The painter’s skin must be in contact with the electrostatic discharge bracket. Ignoring this point is fraught with electric shock.
- Fill the hopper with paint.
- That’s it, the gun is ready to go. Pull the trigger and paint.
The process of working with a tribo gun is exactly the same, only it does not need to be plugged into an outlet.
When you pull the trigger, compressed air flows to the ejector. It sucks in paint from the hopper and mixes it with air.
Use the knob on the back of the gun to adjust the mix.
After you have completely covered the product, transfer it to the curing oven. The time it stays there depends on the materials and can range from 7 minutes to half an hour.
How to paint complex shapes
If you have to paint a product with a complex shape, reduce the air pressure to 0.1-0.2 atm, and bring the powder paint gun closer to the surface.
If the product has sharp corners or interior corners, start painting from there. Keep the gun at a distance of 10-15 cm from the surface. In this case, the pressure should be low. After processing the corners, the pistol must be removed 25-30 cm from the surface, and the pressure can be increased to 1 atm.
Working with a gun: problems and solutions
And now a little about the most common problems that all painting operators are faced.
Flying from the gun, paint forms a torch. It may be weak or absent at all with normal air supply. This means that the channels of the ejector and the air path are clogged. It is easy to fix this problem: unscrew the ejector and blow with air. Then sift and dry the paint.
If paint does not settle on the product, reduce the air pressure. Also check the grounding of the product. It may be worth cleaning the suspension or replacing it with a new one. When working with “antiques” and “metallics” the barrel is constantly clogged. This is another reason the paint does not adhere to the surface. Clean the barrel regularly with air and a cleaning rod.
Sometimes bubbling may not work. The reason for this is the clogging of the air supply channel to it. Remove the hopper from the handle, unscrew the sparge adjustment knob and clean the hole with a thin wire.
Miss following the spraying gun rules usage leads to electric shock. Check if the skin is in contact with the metal grounding bracket on the handle. Try cleaning the bracket. Also, an electric shock can be triggered by a malfunction of the trigger or reed switch. Replace parts and keep working!
