Powder Coating: RAL Colours, Thickness & Limits
A thicker, tougher coating than anodising for parts that need colour and impact resistance — with a size limit worth knowing.
Request a quoteWhat actually happens to the part
Electrostatic powder is sprayed onto the part, which is electrically charged so the powder is attracted and sticks. The part then goes into an oven where the powder fuses into a continuous film.
| Parameter | Value |
|---|---|
| Standard polyester | 60–80 µm, indoor use |
| Polyester outdoor | 80–100 µm, UV stable |
| Powder coat + anodise | Hard anodise then powder for colour and wear |
| RAL colours | Full RAL and Pantone matching |
| Masking | Threads, bores and datum faces can be masked |
| Surface roughness | Ra 0.8–2.0 µm, typically gloss or matt specified |
| Typical lead time added | Add 3–5 working days to the machining time |
What this finish does to your tolerances
This is where most prototype surprises come from. A finish is not decoration — it moves dimensions, and the drawing has to account for it.
A 60–100 µm film is substantial — far more than anodising. It fills detail, rounds sharp edges and closes small holes. Threads need masking, and a shaft that has to fit into a bearing should be machined undersize or masked.
Suitable for
- Aluminium
- Steel
- Galvanised steel
- Mild steel
Not suitable for
- Thin-wall parts that distort in the oven — a 1 mm wall on a large part can move
- Precision fits and bearing seats without masking
- Parts with an operating temperature above the coating limit, typically 200 °C
- Very fine surface detail — a 60 µm film rounds it off
What engineers ask about Powder Coating: RAL Colours, Thickness & Limits
Why does powder coating cost more than anodising?
It is a thicker film and a higher-temperature cure, so more process time and more masking. In return you get impact resistance and the full RAL colour range, which anodising cannot match.
My part came out with a slightly different colour than the sample. Why?
Most often a batch difference on a metallic or a thin-film colour, or a difference in surface texture underneath showing through. We approve a physical panel before the batch runs.