Electrostatic Painting Guide

Electrostatic painting is a popular spray painting method that results in a seamless factory finish, giving  metal objects a brand-new appearance. The results of an electrostatic coating are similar to powder coating, but the process is faster and has fewer drawbacks. This guide will explain everything you need to know about electrostatic painting and help you decide if  it’s the right choice for your project.

What Is Electrostatic Painting?

Electrostatic painting is a painting method that sprays electrostatically-charged paint that clings to metal objects. When the paint droplets are forced out of the sprayer, they receive a positive electric charge, and the droplets are drawn – like a magnet – to the negatively-charged metal surface.

The electrostatic attraction is several times stronger than gravity, meaning you can attempt to spray the paint past the object, and the paint droplets will turn and land on the metal surface. This wraparound effect creates an even coating, because the more paint lands in one spot, the less attraction there will be causing the next droplets to land somewhere on the object where there is a thinner layer of paint, or no paint at all.

Electrostatic painting is an innovation that was discovered in the pursuit of minimizing the amount of wasted paint during the painting process. It can be used on most metal surfaces including:

  • Metal walls
  • Metal doorways
  • Elevator doors
  • Metal fences
  • Industrial equipment
  • Metal tables and chairs
  • Metal light fixtures
  • Items with metal trim
  • Lockers
  • Filing cabinets
  • Shelving
  • Fences
  • Handrails
  • Most metal objects

Why is an Electrostatic Spray Gun So Efficient?

Using traditional spray painting methods means that some paint is going to miss the object and land on the floor or nearby surfaces. This wasted paint costs money and needs to be cleaned up later. Electrostatic spraying is an extremely efficient painting method because the charged paint droplets are attracted to the negatively-charged object. The efficiency is clear, because regular spray painting will result in 20% to 60% overspray, and electrostatic spray painting will have only around 5% overspray, which equates to 95-98% transfer efficiency.

Electrostatic Paint Types

Electrostatic sprayers need the paint to contain solvents so it can carry a positive charge. Solvent-based high performance urethane paints are the most commonly used for this type of painting.

Electrostatic Paint Colors

Electrostatic paint is available in the full spectrum of colors. You can even match them to existing color samples so you’ll have the perfect shade for your brand and product.

A Brief History of Electrostatic Painting Technology

Electrostatic finishing was invented in 1931 by Harold Ransburg. Harold had to leave school to help at his father’s business, the Harper J. Ransburg Co. During Harold’s work of painting stoneware and metal housewares, he experimented with equipment known to charge paint particles, and developed a system of electrostatic painting called the “No. 1 Process.” The process was widely used for painting of munitions and supplies during World War II.

As he continued experimenting, Ransburg learned he could negatively charge the atomized paint particles and also charge the item to be coated — or make it a neutral ground — creating an electrostatic field. This field then pulls paint particles to the item. Through innovation, Ransburg developed the No. 2 Process in 1948 and introduced a spray gun for that process in the mid-1950’s. The electrostatic painting process and equipment became more widely used in the 1960’s.

Advancements, including applications outside of painting, continue today. Commercial and industrial businesses, and institutions like schools, hospitals and governments, can benefit from electrostatic painting technology and processes that have been refined for more than 80 years. At Alpine Painting and Restoration, we use this dependable process to make your projects the best they can be.

How Does Electrostatic Painting Work?

From the start to the end of the electrostatic painting process, the operator uses the specialized equipment to atomize the paint and control the connectivity and flow between it and a grounded target.

To receive a charge and be electrostatically attracted to its surface target, the conductivity and resistivity measures of paints used should be known. Electrical resistivity represents a measure of how strongly a material opposes the flow of electric current. Paint with a low resistivity readily allows the movement of an electric charge.

Conductivity represents the reciprocal quantity to resistivity and a measure of a material’s ability to conduct an electric current. For some projects, water-based paints may be too conductive and not used with electrostatic painting equipment.

In powder coatings, conductivity agents are not needed as much because the electrostatic paint gun nozzle atomizes the particles. Fewer conductivity agents contribute to a reduction or elimination of pollutants.

The Locker Target Example

As an example, let’s look at a project for which you would hire a painting contractor like us to complete — restoring lockers in a high school gymnasium locker room. We would refer to the lockers as the “target” on which the paint will be sprayed.

Before spraying, we will complete preparations typically done to surfaces that will be painted. For metal surfaces, this includes steps to remove dirt, contaminants, loose paint, rust, scratches or graffiti.

For every project, prep work also includes mixing the paint according to instructions provided by the electrostatic painting equipment manufacturer. Adherence ensures proper atomization, viscosity, conductivity levels, even application and safety.

When we start the painting process, we will use the paint gun equipment to charge the paint particles. Electrostatic painting equipment manufacturers refer to this as atomizing the paint. Scientists and engineers refer to the process as ionizing the paint particles.

The charged particles of the paint gun create an electrostatic field between the paint gun nozzle and the grounded target. Principles of electrostatics come into play. With the paint particles atomized, the grounded locker target pulls the oppositely charged particles to it. We use this attraction to guide the flow of the charged particles through the paint gun nozzle.

The paint particles land and bond only to the open surface area that’s grounded. As the particles coat the target, the charge dissipates and returns to the power supply through the ground, completing the electrical circuit. Because the charge of the target locker surface changes once the bond between the unlike charges occurs, the coated area stops pulling paint particles to it.
The electrostatic process is completed with an even, high-quality application of the coating. Most of the atomized particle spray from the paint gun lands on and bonds to the locker. Engineers call this “high transfer efficiency” and have measured this paint application efficiency rate at over 90 percent when optimized.

How Can an Electrostatic Painter Be That Accurate?

With the right tools, a commercial painter can use electrostatics to influence the path of the paint because the particles are small enough to be controlled by the charge from the paint gun. At indoor project sites, the painter has added influence to minimize air currents that might interfere with paint particle flow, and, therefore, has more control over how fast the particles move to the target. This gives the electrostatic paint gun operator the power to optimize paint and time use.

The painter’s selection of paint also contributes to the effectiveness of the electrostatic painting system equipment, as some particles accept an ionizing charge more readily than others. Equipment manufacturer engineers consider this when designing and producing the products, and they will recommend the products that meet the highest transfer efficiency standards while balancing finish quality standards.

What Is Wrap or Wraparound?

Electrostatically charged paint particles are so attracted to the grounded target that they tend to coat the side, edge, corner and backside surfaces that aren’t facing the atomizer. This tendency reduces touch-up and clean-up labor, and it increases the ratio of surface covered to paint volume.

What Equipment Does Electrostatic Painting Require?

Equipment required to paint items brought to an electrostatic painting facility differs from equipment required to go to a client’s location where on-site work will be completed and proper grounding safeguards applied.

Here we focus on equipment for commercial, industrial and institutional painting or restoration projects that must be completed at the location of the items to be painted. The electrostatic painting process equipment for this purpose must be a portable system that includes the following:

  • Paint gun with atomizer: The main piece of equipment for electrostatic application of paint. Over time, paint guns have become lighter in weight, optimizing their portability to work at client sites. Most important to the design of the gun are its ionizing apparatus and sprayer with a resistive, high-voltage circuit that builds in safety. These may be automatic or manual. This design works ergonomically to make finger control of the on/off switch and handling of the spray nozzle simple. Many paint gun designs integrate voltage control to allow the gun operator to easily adjust between a range of voltage levels.
  • Bell: At the end of the nozzle, the bell controls the delivery rate of the paint and the paint application rate. The bell can be switched out depending on the size and shape of the objects to be painted as well as other requirements of the specified project.
  • Tank: The tank holds the paint until it’s pushed up through the fluid hose to the paint gun. Tank sizes range in gallon capacity, allowing electrostatic paint system operators to choose a reservoir size that fits the project size, mobility needs and space limitations of the work site.
  • Compressor: This system component controls the mechanism that pushes the paint from the tank to the paint gun. Compressors include pollution control functions and safety features.
  • Power supply for the paint gun and compressor: This is basically a generator with a series of high and low voltage power settings for electrostatic paint applicators, adjustable to the operator’s use of a gun or industrial rotary atomizer. The power supply controls the transfer efficiency of the paint gun while maintaining safety. Display panels on the power supply unit allow the operator and worksite manager to easily monitor and adjust voltage or current. Safety features include displays that indicate cable faults or overloads, and a reset switch.
  • High voltage cable: As part of the electrostatic painting system, an integrated part to ensure safe operation.
  • Fluid hose: Connects the compressor to the paint gun, serving as the channel through which the paint particles travel before atomization.
  • Cart: Designed to organize the system components, the cart allows for easy portability of the equipment to and at the work site. Like other components, the design integrates system safety.
  • Accessories: These come in the form of finishing applicators that can be attached to the end of the paint gun nozzle. Painters will use these according to the project needs and worksite specifications.
  • Multi-valve assemblies: When needed, multiple valves make changing fluid supply easy for projects requiring multiple colors or application of various coatings.
  • Flow control systems with monitors: These allow operators to more efficiently control paint usage.

Manufacturers of electrostatic painting process equipment sell the components as integrated systems. This ensures reliable operation, quality finishes and safety. At Alpine Painting and Restoration, we use Ransburg equipment to ensure quality control and that your project comes out smoothly.

Top 8 Benefits of Electrostatic Painting

The benefits of electrostatic painting come from the technology that leverages electrostatic principles. A combination of paint application equipment and paint formula technology has revolutionized our ability to restore commercial, industrial and institutional assets.

Because of innovations in technology over eight decades, you can realize the following benefits in choosing restoration over discarding or replacing valuable or expensive items:

1. Reduction in Wasted Paint

When you hear painting and restoration professionals talk about the electrostatic painting process, you’ll hear them often refer to the paint as “coating.” When you watch the electrostatic painting process, and how the paint particles wrap to the surface as the sprayer moves around the corners and curves, you’ll understand why.

It’s the wrapping quality the paint takes on that maximizes the amount of pigment that attaches then bonds to the surface and reduces the amount of paint that misses the target. The transfer efficiency, or percentage of the paint used without waste, is a high percentage of the amount loaded in the sprayer.

That waste reduction could translate to savings of anywhere between $25 and $75 per gallon of paint, depending on other high pressure or air assisted method the electrostatic coating process replaces.

One of the biggest advantages of electrostatic painting is that it has such a high transfer rate. Due to the electrostatically-charged paint, around 97% of the paint will land on the object. This is compared to a conventional paint sprayer which only has around a 40% transfer rate, the rest of which lands on the ground. The extremely low paint drift of electrostatic sprayers means far less wasted paint than other methods, which saves you money.

2. A Smooth and Seamless Electrostatically Painted Surface That Looks New

The quality of finish achievable with electrostatic paint application can truly make a facility with some years behind it look new. 

3. Fast Painting and Dry Times Mean Shorter Down Time for Your Business

Similar to air spraying methods, the electrostatic process makes paint application fast. Electrostatically applied paint dries faster than wet spray methods and doesn’t require high-heat ovens. You no longer have to wait for weeks with rooms temporarily out of use or for fumes to dissipate. Normal business can resume within days.

4. A Durable Finish for Your High-traffic, Heavy-Duty Use

The bonding properties possible with the electrostatic process make for strong protection against corrosion, weather wear and heavy use. Durability can be especially valuable where your assets may be exposed to indoor or outdoor humidity and moisture.

5. Overall Savings in Money and Time

The next time you’re considering discarding items that are still functional but “look old,” consider having a contractor that specializes in electrostatic painting take a look. You may find that restoration is a viable option. The right coat of paint could extend your original investment and protect a still valuable item for years.

6. On-site Application

Instead of having to remove equipment and transport it to another location to be painted and cured, electrostatic spray painting can be performed on-site. That means that there’s minimal interruption of the business’ day-to-day operations, and less downtime, because the paint will have dried within a few hours.

7. Quick Application

Electrostatic painting is a quick and convenient option. Because the paint droplets are attracted to the object with minimal overspray, electrostatic painting can be performed quickly, often with a single coat. And with quick drying and on-site application the process is made even faster.

8. Even Finish

Unlike other painting techniques that can result in bubbles or drips, electrostatic painting results in an extremely smooth and even coat of paint. Many people compare the results to automotive painting.

4 Disadvantages of Electrostatic Painting

Electrostatic painting has plenty of benefits, but there are a handful of downsides as well. To help you decide if this painting method is right for your project, here’s a summary of the common disadvantages to this painting method.

Setup Cost

The primary disadvantage of electrostatic spray painting is the initial setup cost. Electrostatic spray equipment is more expensive than alternative painting methods, but the upside is that it will save a painting company money down the line. That’s because the speed of applications means you’ll spend less money on labor, and the reduction in overspray means you’ll save money on paint.

Employee Training

A downside for painting contractors that add electrostatic spraying is that they’ll need to train employees to use an electrostatic sprayer and how to clean it. However, this investment in training will result in savings down the line, as the electrostatic sprayer will allow employees to apply paint faster and with far less waste. These savings result in a quick return on investment.

The Faraday Cage Effect

When using an electrostatic sprayer, it can be difficult to paint the inner corners of metal objects – like the inside of a metal locker – because all three negatively-charged surfaces  of that corner will be pulling the paint toward it with equal force, known as the Faraday Cage Effect. The solution for this is to simply airspray the inner corners of the object, and then use the electrostatic sprayer to paint the rest.

Only for Metal Objects

The final disadvantage of electrostatic painting is that it can only be used on conductive objects like metal. The positively-charged paint will be pulled toward and cling to a grounded metal object, but not to objects made from non-conductive materials. This limits the usability of this method.

Electrostatic Painting vs. Electrostatic Powder Coating

Electrostatic powder coating and electrostatic painting are two similar painting methods, with a few key differences. Both options use a sprayer to apply positively-charged paint to metal objects and surfaces, but the main difference is that powder coating is dry, while electrostatic paint is wet. 

After powder coating is applied, it needs to be placed in an oven for the process to complete. That means that any objects or machinery that receive powder coating must be removed from the facility and transported off-site to be painted and baked. Electrostatic spraying can be painted on-site, and dries within hours without the need for an oven.

The upside to powder coating is that after the paint has cured, it creates a thicker, longer-lasting coat of paint than an electrostatic spray. They’re comparable options, but electrostatic spraying is simpler and easier to do than powder coating. Most customers prefer electrostatic painting due to its speed and convenience.

Electrostatic Painting vs. Spray Painting

The equipment needed for electrostatic painting is more expensive than conventional spray painting, but the amount of paint you save with electrostatic saves you money over time. Spray painting is simple. It doesn’t require special training or expensive equipment, and can be applied to any surface, but it can result in a sloppy, uneven coat of paint, and much of the paint used will be wasted due to overspray.

The primary benefit of electrostatic painting is that the positively-charged paint droplets are attracted to the negatively-charged metal surface, which means minimal paint loss. It also results in a smooth, even coat of paint, like the painted object came direct from the factory. The downside is that electrostatic spray painting can only be used on metal objects. In situations where a metal object needs to be painted, electrostatic painting is the preferable method over spray painting.

Is Electrostatic Painting Right for Your Project?

Thanks to its speed and efficiency, electrostatic painting has been a popular option for repainting metal objects like interior office assets and industrial equipment for more than fifty years. Professional painters love its easy application, quick drying, and minimal paint wastage. If you have a complex metal structure, or aging metal equipment that’s in need of a refresh, electrostatic spraying is a smart choice.

Trust Alpine Painting and Restoration for Your Facility Painting Needs

When choosing a painting and restoration contractor for your commercial and industrial needs, you’ll want one whose business longevity reflects the enduring trust of satisfied clients. You should also choose a contractor whose electrostatic painting equipment operators are knowledgeable in all aspects of the process, equipment and materials, and disciplined in their safety practices.

For restoration and painting, and especially budget-conscious, safety-imperative methods like electrostatic painting, the level of trust you’ll need is high. Alpine Painting and Restoration has been delivering safety at the worksite and high-quality final results to satisfied customers since 1990.

We’ve seen many technologies and methods come and go for almost three decades now. Today’s electrostatic painting, which has been around for the last decade, may improve or eventually be replaced by another technology or method — but our approach will always be to apply current methods and technologies for durability, longevity and budget. Our customers will always see that in the quality of service and safety we deliver on-site, including our safe use of equipment and grounding practices.


To learn more about electrostatic painting in the Philadelphia area for commercial and industrial assets such as building interiors, exteriors and equipment, contact us online or call us at 215-348-4410. We can show you samples of the quality surface protection, durability and aesthetic presentation electrostatic painting delivers for your most valued assets.

Last Updated: October 11th, 2024

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