The Advantages of Electrostatic Spray Painting

Electrostatic spraying is a coating method that uses a spray gun to positively charge electric particles while the workpiece is grounded, or negatively charged. The process delivers high transfer efficiency, reduces costs, and can improve environmental performance. The advantages of electrostatic spray painting make it a popular application choice for paint shops. Here we explore the process, its benefits and its disadvantages in more detail.

How Does It Work?

Electrostatic spraying works on the principle that:

Particles with a negative charge attract particles with a positive charge.
Particles with a positive charge repel other particles with a positive charge.

The electrostatic process

A positively charged electron within the spray nozzle charges the paint particles. Because these particles all have a positive charge, they repel each other and break apart, resulting in a fine mist that coats evenly. There is also a magnetic effect. The negative charge of the workpiece attracts the positive charge of the paint particles across its full surface. Once coated to a certain depth, the workpiece stops attracting paint particles because the negative charge is too weak. This results in an even finish.

The "wrap-around" effect

Paint particles with a positive charge 'seek out' uncoated surfaces with a negative charge. This means that the backs and sides of a workpiece draw paint toward them once the front side is coated.

What Are the Advantages of Electrostatic Spray Painting?

Electrostatic technology has three distinct advantages over conventional air spray and HVLP guns:

Superior quality coating with a faster production time

Electrostatic sprayers create a flawless and durable finish that dries quickly. Unlike brushes, rollers and other types of sprayer, they can also reach corners, crevices and the backsides of surfaces. This reduces production time, especially when spraying tubular products.

Low VOC emissions

VOCs are chemicals found in paints to:

Preserve them
Enhance their flow
Create specialist properties such as resistance to corrosion

During the paint application process, VOCs evaporate and are released into the air as gases.

VOC levels and the law

High VOC exposure can have serious effects on human health and on the environment. For this reason, industrial paint shops must comply with:

Control of Substances Hazardous to Health (COSHH) Regulations
Volatile Organic Compounds VOC in Paints, Varnishes and Vehicle Refinishing Products Regulations 2012:1715
The Solvent Emissions (England and Wales) Regulations 2004, SI 107
Environmental Permitting (England and Wales) Regulations 2010 SI 675

For further details on these Regulations and how to comply, visit the HSE, British Coating Federation and UK Government websites.

Electrostatic spray painting and VOCs

The Solvent Emissions (England and Wales) Regulations 2004, SI 107 requires that you inform your local authority and apply for a permit if you consume more than 5 tonnes of VOCs per annum. Permits cost almost œ2K p/a and failure to comply can result in hefty fines and litigation. The high transfer efficiency of electrostatic spraying can help you to comply with VOC limits by reducing:

The number of VOC-containing products that you consume
Your VOC emissions
The volume of hazardous waste that you produce

Cost savings

Electrostatic sprayers have a high transfer efficiency of up to 90%, resulting in less:

Paint wastage
Clean-up and associated cleaning product and labour costs
Spending on the disposal of hazardous waste

This is because:

The "wrap-around" effect makes use of spray that would ordinarily be lost as overspray.
Electrostatic sprayers don't need air pressure to atomise paint particles. Conventional sprayers do rely on air pressure, which creates more spatter and overspray.

Are There Any Disadvantages?

When considering adopting a new application process it's important to assess the disadvantages too. To help you do that, here's a summary of the three common disadvantages and their implications:

Set-up cost

Compared to other application methods, the purchase and set-up costs are high. However, with reduced labour and material costs, the return on investment is greater than for other types of application.

Training the workforce

You will need to train your sprayers to use the new equipment and to maintain and clean it correctly. However, painting electrostatically will save your team time, turning training costs into savings.

The Faraday Cage Effect

An electrostatic spray gun can struggle to coat deeply recessed workpieces, such as metal lockers. This is because the paint is attracted toward the nearest negatively charged surface, which in this case, is the sides of the locker. To overcome this, spray the recess with an airless gun and then finish electrostatically.

Conclusion

The advantages of electrostatic spray painting make it an ideal application method for paint shops that want to:

Produce a superior finish
Reduce production costs
Improve their environmental performance

If you're considering switching to electrostatic technology, we can help you with your decision. Book a site demo by contacting us below or using the contact us form above with a member of our sales.