An HVLP paint spray, or High Volume Low-Pressure, paint spray is a device used to spray paint at a pressure that is easy to control and direct. They produce a fine, smooth, and consistent finished paint surfaces that cannot be achieved by any other tool. Unfortunately, most people do not take the time to learn how to operate them.
That leads to frustration when they become unable to get the desired outcome when spraying the HVLP paint spray. That leads many hobbyists and beginner painters to conclude either the device is to blame, or HVLP sprayers aren’t as great painting tools as they are said to be. That’s why we have deiced to write on the subject, “How Do HVLP Paint Sprayers Work?”
Operating Principle: How do HVLP Paint Sprayers Work
Paint spray guns turn liquid paint into hundreds of thousands of tiny droplets, a process called atomization. The atomized droplets allow the paint to be spread in almost to a molecular level on the surface of the work piece.
The HVLP Paint Sprayers guns are equipped with several components that work together in unison. The HVLP Paint Sprayers guns are the latest spray technology and therefore the most efficient. Other past technologies are pressure siphon sprayers and gravity-feed sprayers.
In the pressure guns, the fluid was pressurized and then allowed to flow out through a small opening, controlled mostly by a valve that could be actuated by hand. In siphon guns, the flow of air past the reservoir, create a low pressure that sucks out the paint and splits it into small particles as it exits from the gun’s opening.
Gravity-feed guns have the reservoir mounted on top of the gun. That takes advantage of the force of gravity to draw the paint downwards where it combines with a high-speed exiting jet.
The HVLP Paint Sprayers guns feature either the siphon or gravity-feed designs. They are unique in that they work at low pressures, typical between 10 psi to 20 psi. They are cable of spraying a significantly large volume of paint with minimal waste (this also happens to be their main strength). Their ability to transfer large ratios of paint to the work surface and having minimal overspray means that HVLP sprayers can be used where efficiency and accuracy are highly preferred.
The HVLP reservoir’s main job is to hold the paint and allows the atmospheric pressure to act on the paint. That allows it to flow downwards by gravity. Most siphon paint guns have reservoirs that can contain up to a quart of paint while the gravity-feed reservoirs hold up to a pint of paint. The atmospheric pressure is able to act on the paint through a non-spill valve or ventilation.
When operating the paint spray gun, there are three things to remember; the air pressure, the paint flow, and the fan size. The best inlet air pressure that is recommended by most manufacturers is 30 psi to 50 psi. While using a greater air pressure than that will atomize the paint more, it will also cause an overspray. Over atomization also increases the “orange peel” phenomenon because the solvents in the paint dry much faster than the paint pigments.
The fan determines how wide the paint spray pattern will be. Using a wide fan means that the amount of material distributed decreases. That means that you may need to spray the same area more than twice to get the desired finish.
It is now possible to adjust the paint flow, and you only need to vary it depending on the specific paint you are using. Once you have set it, should remain unchanged until you install a different air needle or air cap.
The Air Cap is the final component that determines how the spray is going to appear. It has holes drilled with precision and placed in such a way that they will produce the best pattern on the paint surface. Air entering these holes atomizes the paint and creates a pattern that has a fan’s shape.
While setting the three features can help to get the best pattern, overall, you need to prepare the paint to the desired quality and do a few tests with different settings. Once you get the pattern you want, note that setting for that paint and you will never go wrong again.