Powder coating and RAL colours for metal furniture

1. Pretreatment: degreasing and a conversion coating so the powder bonds and rust cannot creep under the film.
2. Drying.
3. Powder application: electrostatic spray guns charge the powder so it clings to the earthed part.
4. Curing: the part is baked, typically at about 180 to 200 °C, until the powder flows and hardens.

On a conveyorized line the parts hang on a moving track through each stage, which keeps time and temperature the same for every piece.

RAL is a colour-numbering system used across Europe and by most powder makers. Each shade has a four-digit number, for example RAL 9005 jet black, RAL 9016 traffic white, RAL 7016 anthracite grey and RAL 7035 light grey. Quoting the RAL number, not a colour name, is the simplest way to get the same colour from every batch and every supplier.

• Matte: low reflection, hides fingerprints and small surface marks. Popular for workstation frames.
• Satin or semi-gloss: easy to clean, a common default.
• Gloss: bright, shows surface defects more.
• Textured or wrinkle: hides weld dressing and resists scuffs.

For indoor furniture a cured film of roughly 60 to 80 microns is typical. Too thin and edges show through; too thick and the film can look orange-peeled or chip. If your customer specifies a thickness, state it in the order so it can be measured.

• Colour against an approved sample panel, in daylight.
• Coverage inside corners and at tube ends.
• No pinholes, runs or bare edges.
• Adhesion: the film should not flake when scratched at a hidden spot.