How powder coating works
Powder coating is a factory process. A dry powder, made of resin and pigment, is sprayed onto the metal with an electrostatic charge so it clings to the surface. The item then goes into an oven, where the powder melts and cures into a hard, continuous film.
Because it needs an oven, powder coating has to happen before the metal is installed, or the item has to be removed and taken to a coating plant. It's an excellent finish for new windows, balustrades and fabrication coming straight out of the workshop.
How electrostatic painting works
Electrostatic painting uses liquid paint instead of powder. As the paint leaves the spray gun it's given an electrical charge, and the earthed metal attracts it. The paint wraps around edges, bars and the back of rails, giving an even coat with far less overspray than conventional spraying.
The big difference is that it doesn't need an oven. It's applied on site, with the metal exactly where it is. A typical system is thorough cleaning and preparation, an epoxy etch primer for adhesion, two colour coats, and a hard-wearing polyurethane topcoat.
When each is right
- New fabrication, not yet installed: powder coating in the factory is usually the most efficient choice.
- Installed windows, balustrades, stairs and gates: onsite electrostatic painting, so nothing has to be removed.
- Changing colour: onsite electrostatic. Going from cream or bronze to black, for example, without new frames.
- Repairs and defects: onsite electrostatic. Installed powder coat can't be re-baked, so scratches and chips are fixed with a colour-matched liquid coat. See powder coat repair.
- Welded or site-modified steel: onsite electrostatic, applied after install. See steel & fabrication.
What decides durability
People often ask which is "stronger". In practice, how long a finish lasts depends far more on these factors than on the method:
- Preparation. Cleaning off salt, grease and chalky oxidation, and keying the surface. Most coating failures start with poor prep.
- Primer. The right primer for the metal, whether aluminium, steel or stainless, so the coating bonds properly.
- The coating system. Number of coats, film build and the topcoat used, especially for coastal or high-traffic areas.
- Warranty. Ask what's covered, for how long, and whether it's in writing. A specialist will be clear about this before you commit.
Side-by-side comparison
| Factor | Onsite electrostatic painting | Powder coating |
|---|---|---|
| Where it's applied | On site, with the metal in place | In a factory, before install |
| Coating type | Charged liquid paint (primer, colour, topcoat) | Dry powder, oven-cured |
| Removal needed | No | Yes, if already installed |
| Best for | Installed metal, colour changes, repairs, defects | New fabrication before install |
| Spot repairs | Yes, colour and gloss matched | Not once installed (can't be re-baked) |
| Colours | Any colour, solid, metallic or pearl, any gloss | Wide range, set before fabrication |
| Disruption | Masked work area, nothing removed | Removal, transport and reinstall if installed |
Can you combine the two?
Yes, and on many projects that's exactly what happens. New balustrades or windows are powder coated in the factory, installed, and then damaged by other trades before handover. Rather than sending them back, we repair and colour-match them on site. Years later, when the owner wants a new colour, the same powder-coated frames can be resprayed in place. The two methods work together over the life of the metal.
The key is matching the existing finish. We match both colour and gloss level, including metallics, and test before we spray, so the onsite coat sits naturally beside the original powder coat.
The bottom line
Powder coating is the right finish for new metal before it's installed. Once it's on the building, onsite electrostatic painting lets you change the colour, fix damage or refresh a whole home or building without removing anything, usually for a fraction of the cost of replacement. If you're not sure which your job needs, send us a few photos and we'll tell you honestly.
Planning a colour change? Start with aluminium window respray or balustrade painting.
Common questions
Is electrostatic painting as durable as powder coating?
Durability depends on preparation, primer and the coating system more than the method. With proper prep, an etch primer and a hard-wearing polyurethane topcoat, an onsite electrostatic finish is built for Australian conditions. Factory powder coat on new metal is also very durable. They suit different situations.
Can you powder coat something that's already installed?
No. Powder coating needs the item to be baked in an oven, so installed windows, balustrades and stairs would have to be removed. Electrostatic liquid painting is applied on site instead.
Can you paint over existing powder coat?
Yes. We clean and key the existing powder coat, prime it for adhesion and apply new colour coats. This is how we repair and recolour installed powder-coated frames.
Which is cheaper?
For new fabrication, factory powder coating is usually the most cost-effective. For installed metalwork, onsite electrostatic painting is usually far cheaper than removing, recoating and reinstalling, or replacing it.
Can you match a powder coat colour?
Yes. We match colour and gloss level on site, including metallics, and test before we spray.