PROCESS & FINISHES
When it comes to refurbishing your alloy wheels, you are faced with a critical choice:
a full powder coat finish, or a diamond cut finish.
When it comes to refurbishing your alloy wheels, you are faced with a critical choice: a full powder coat finish, or a diamond cut finish. Making the wrong choice can lead to premature corrosion, especially in Cornwall’s coastal environment, or ruin the aesthetic value of a premium vehicle. Powder coating is an industrial process that encases the wheel in a highly durable, oven-baked polymer shell. Diamond cutting is a precision engineering process that machines the face of the wheel on a CNC lathe to reveal the bare aluminium, creating a stunning, high-contrast, two-tone effect. Both processes require heavy workshop machinery—neither can be properly executed on a driveway.
The wheel is submerged in a chemical bath to dissolve all old paint and lacquer back to bare metal.
The bare alloy is blasted with aluminium oxide to create a microscopic texture for the powder to grip.
Heated to 200°C to force trapped air out of the porous cast aluminium, preventing bubbles in the finish.
An electrostatically charged dry powder primer is applied, wrapping around the entire wheel structure.
The base colour is applied, followed by a highly durable, oven-cured clear powder lacquer.
Powder coating creates an incredibly tough shell that is highly resistant to stone chips, brake dust, and salt corrosion.
The wheel undergoes the exact same stripping and powder coating process described above to apply the base colour.
The painted wheel is mounted on a highly precise Computer Numerical Control (CNC) industrial lathe.
A laser probe maps the exact curvature of the wheel face, creating a digital profile for the cutting tool.
A diamond-tipped cutting tool shaves a microscopic layer of metal off the face, revealing the shiny aluminium beneath.
Because the face is now bare metal, a specialised anti-corrosion clear lacquer is applied and baked to seal the wheel.
Produces the sharp, two-tone 'CD-like' finish found on 90% of modern vehicles (Mercedes, BMW, Audi).
Your geographical location should heavily influence your choice of finish. In Cornwall, the combination of coastal salt air and winter road grit creates a highly corrosive environment. Diamond cut wheels look spectacular, but the clear lacquer is bonded directly to smooth, bare aluminium. If a stone chip breaches that lacquer, salt water will seep underneath, causing the lacquer to lift and the aluminium to oxidise (a milky white spreading stain known as ‘white worm’). Powder coating, however, uses an etched primer bonded to the metal, making it vastly more resilient. If durability is your primary concern, powder coat is the superior choice.
Yes. Because the wheel is powder-coated before the face is machined, you can choose any colour for the ‘inserts’ (the sides of the spokes and the barrel). Black and Anthracite are the most popular choices to contrast with the shiny metal face.
Absolutely, and we highly recommend this for older vehicles or for customers wanting a lower-maintenance finish. We simply strip the wheel and apply a full powder coat over the entire surface.
Most don’t. Mobile vans use orbital hand sanders to try and mimic the finish of a CNC lathe. It leaves a dull, scratched surface rather than a precise machined cut. True diamond cutting requires a 3-tonne industrial lathe. Some vans carry a lightweight lathe but still only seal the cut finish with automotive lacquer rather than a stoved acrylic powder lacquer. They charge the same or more.
Powder coated wheels are generally easier to clean and can withstand stronger wheel cleaning chemicals. The lacquer on diamond cut wheels is more delicate and requires pH-neutral cleaners to prevent clouding.
Not sure which finish is best for your vehicle and driving habits? Contact our St Day workshop for expert advice.
