Electrostatic Spray Painting Basics Explained
Electrostatic spray painting is a method that can reduce problems with uneven coverage and overspray that result from using a regular spray painter. It's an easy process, if a little expensive to buy the tools. Although it does create a worthwhile result if you're willing to put forth the money, you should learn all you can about the technique before investing in your own sprayer or paying someone for an electrostatic paint job.
How Does it Work?
The paint applied by these types of sprayers can be both liquid or powder, and it is electrostatically charged in a couple of different ways. One type of system applies a negative electric charge to the paint while it is in the reservoir. Other systems apply the charge in the barrel of the spray painter gun. The paint is then propelled through the gun, rubbing against the side, and gaining a static electric charge as it moves.
Since the paint particles all have the same charge, they repel each other. This helps to distribute the paint particles evenly and get uniform coverage. Usually the object being painted is metal and grounded, but almost any product can be finished electrostatically. A metal object may need to be placed behind the object to create a ground or the object can be sprayed with a conductive primer. The paint particles have a charge so they are attracted to the opposite charge of the object being painted. This makes the particles less likely to stay in the air.
Pros and Cons
Electrostatic spray painting has distinct advantages. It creates a strong bond. It also covers a three dimensional object more evenly with good edge and wrap-around coverage. It saves paint by having a high transfer efficiency, using less to finish the project than a regular sprayer. Also, the finish will look better because it has a very uniform paint thickness.
There are some disadvantages as well. Material to be sprayed must be conductive or made conductive for proper bonding. Care has to be taken with this equipment as guns can be delicate and bulky, and improper usage can be a safety or fire hazard. Lastly, it is more expensive to apply than regular spray painting, as we mentioned previously.
Equipment and Additional Materials
The equipment that normally comes with an electrostatic spray unit includes a spray gun, air and paint hoses, and a grounding cable. You will also need two types of adapters. A round tip is for irregularly shaped objects and the flat tip adapter is for painting large flat objects.
In addition to the sprayer, you will need some other materials to actually do the job. Get tape for taping off areas not to be painted, as well as drop cloths to protect surfaces and a bucket for mixing paint.
Note: When using this equipment you should take safety precautions. Work in a ventilated area where the heaters have been turned off. Protect yourself by using eye and ear protection along with clothing that covers most of your skin. These sprayers are under enormous pressure so never point the spray gun at yourself or anyone else.
Here are the basic steps you will need to follow when painting with an electrostatic sprayer.
Step 1 - Select and Add the Paint
Choose the right material to be sprayed. Your choice of paint will depend on the appearance you want and the item you're painting. If a powder is used instead of a liquid paint this process is called powder coating. It is commonly used on things like bike frames and metal file cabinets.
Once you know what you're using, go ahead and load the paint to be sprayed into the bucket, making sure you're familiar with your sprayer's directions just in case.
Step 2 - Test the Sprayer
Always make sure to test your sprayer first to avoid making any mistakes on your surface. First, turn on the spray and prime the pump. Perform the first spray to check that you have an even fan pattern. Then, turn on the electrostatic and do another test of the fan pattern. If it distributes as it should, you can move forward. If not, you will need to troubleshoot the device.
Step 3 - Apply Paint
Spray the object using even strokes and step back occasionally to check the coverage as you go. When you are done, double-check the entire coat to be sure it looks the way it's supposed to.
Step 4 - Clean up the Sprayer
If everything looks good, it's time to clean the sprayer and put it away. Unscrew the tip and dump the excess material into the bucket or a waste pail. Then, clean the sprayer thoroughly as dictated by your specific model's instructions.
And that's it! The process is simple so long as you are patient and know what to expect out of your device.