On-site electrostatic painting: lockers, furniture, partitions and cabinets

On-site electrostatic painting means spraying an electrically charged liquid paint onto a grounded metal item, right where it is installed. The charge pulls the droplets toward the metal, wraps them around edges and the back of tubes, and reduces overspray. It suits lockers, metal furniture, partitions, cabinets and steel or aluminum frames, after cleaning, scuff-sanding and touching up rusted spots. It does not suit wood, plastic, energized equipment or severe corrosion service.

Replacing lockers, toilet partitions or metal cabinets that are still sound is expensive and ties up the premises. Sending them to a shop means removing, shipping and reinstalling them. On-site electrostatic painting offers a third option: refinish in place, over a few work shifts, with a finish close to a factory coat. This guide is for managers of buildings, plants, schools and institutions in Quebec and Ontario. It complements our comparison of powder vs liquid coating, which covers the choice between shop and field work for industrial parts.

How does on-site electrostatic painting work?

The electrostatic gun charges the liquid paint droplets as they are sprayed, and the metal item is connected to ground. The charged droplets are attracted to the metal, so they also land on the sides and back of parts, not only on the face being sprayed.

This wrap-around effect has three practical consequences:

• Less overspray. A larger share of the paint lands on the item, which reduces the amount of masking and cleanup around it.
• Better coverage of complex shapes. Tubes, ventilation grilles, uprights and edges are covered better than with an ordinary spray gun.
• Uniform finish. The charge tends to spread the film onto edges, often the first areas to wear.

Grounding is the basic condition. Each item is connected to ground with a clamp on a spot of bare metal, and continuity is checked before spraying. An item that is poorly grounded, or insulated by a thick layer of old paint, attracts the droplets poorly and the film becomes uneven. That is also why items standing on plastic feet or fixed to a drywall partition are checked case by case.

This is a liquid paint, not a powder coating: powder needs oven curing, which is impossible on an installed item. Our electrostatic painting service presents the method and the items we handle.

Which items can be refinished electrostatically?

The method suits conductive metal items that can be grounded and isolated from their surroundings: lockers, furniture, partitions, cabinets, frames and railings. The substrate must be sound, without perforating corrosion or major deformation.

Aluminum and galvanized steel can also be refinished, but they need a primer suited to the substrate, because ordinary paints bond poorly to bare zinc or aluminum. The data sheet of the selected primer confirms compatibility before work starts.

Safety colours on cabinets, guardrails and handrails can be restored at the same time. See our article on industrial safety colours and marking.

How are the surfaces prepared?

Surfaces are cleaned, degreased, scuff-sanded and spot-treated for rust, then adhesion is checked before painting. Preparation matters as much as the electrical charge: electrostatic paint on a greasy surface peels like any other paint.

1. Cleaning and degreasing. Oils, fingerprints, stickers and cleaning product residue are removed.
2. Scuff-sanding. The existing finish is lightly sanded to give the new film something to grip.
3. Rust treatment. Rusted spots are treated with power tools to a suitable grade, then primed. Our article on power tool cleaning SSPC-SP 3, SP 11 and SP 15 explains the grades.
4. Adhesion and compatibility test. A trial patch confirms that the new paint bonds and does not attack the old one. See painting over old coatings.
5. Masking and protection. Floors, walls, hardware, glass and locks are protected.

What are the limits of the method?

On-site electrostatic painting has limits related to the substrate, the shape of items, the environment and the expected service. Knowing them avoids choosing the method where it will not last.

• Non-conductive substrate. Wood, plastic, glass and laminate do not hold the charge and cannot be painted this way.
• Inside corners. In deep inside corners, the Faraday cage effect limits deposition; brush touch-up or a gun adjustment is then needed.
• Severe service. A decorative finish applied on site is not an anticorrosion coating for immersion, chemicals or highly exposed exteriors. Those cases call for our protective coatings, which remain our core business.
• Heavy mechanical wear. Surfaces under constant rubbing wear faster than a shop-baked finish.
• Original powder coat. Powder in good condition can be overcoated after scuff-sanding, but adhesion is always checked on a trial patch.

If the parts can be removed and time allows, the shop may still be the better option, as our powder vs liquid coating comparison explains.

How is the work organized in an occupied building?

The work is organized by sector, outside occupied hours where possible, with ventilation, protection and a closed perimeter during application and drying. Items stay in place, which avoids removal, transport and reinstallation.

• Hours. Evenings, nights or weekends in locker rooms, offices and classrooms.
• Ventilation. Liquid paints release vapours; the area is ventilated and ignition sources kept away during application.
• Electricity. Cabinets and enclosures are de-energized and locked out before any work.
• Return to use. Items are handled after the drying time stated on the data sheet, and locks and hinges are checked before handover.

A typical sequence runs over one or more nights: protection and preparation, application of the coat, drying, then removal of protection and inspection before occupants return. A first trial sector lets you approve the colour, the appearance and the organization before the whole building is done.

For larger plant or warehouse surfaces (walls, frames, floors), our plant and warehouse painting service takes over.

How is the result checked?

Appearance, thickness and adhesion are checked, as for any paint applied on site. Appearance is checked visually under good lighting, thickness with a gauge on the metal and adhesion with a test on a witness area using the agreed method.

Common defects (runs, misses in corners, orange peel) are corrected before handover. A short handover record listing the items painted, the colour, the product used and the touch-up areas makes future maintenance easier. Our article on coating inspection describes thickness and adhesion checks.

Frequently asked questions

Is on-site electrostatic painting as durable as a shop finish?

It is generally less hard than an oven-cured powder, but far more durable than a rolled paint on a poorly prepared surface. Durability depends mostly on preparation and use.

Do lockers and cabinets have to be emptied?

Yes. Items must be empty to protect their contents and to allow the inside to be painted if that is planned.

Can the colour be changed?

Yes. A major colour change may require an extra coat to cover the old shade.

Do you do residential work?

No. Our work targets industrial, commercial and institutional buildings, not houses or residential garages.

How do you get a quote?

Send us photos of the items, their approximate quantity, dimensions, finish condition and your occupied hours. Our crews and qualified subcontractors work from LaSalle, in Montreal, Longueuil, Laval and Ontario. Pricing is on consultation, depending on quantity, preparation, access and hours; use the request a quote form and we reply within 24 business hours.