Lessons in Powder Coating: Scratches and Powder Coating

Lessons in powder coating: scratches in the aluminum!

This time in our series of 'powder coating lessons' we want to focus on scratches.

We regularly receive sheet material or profile work with scratches on it. In such cases, we check whether these scratches are actually present on the visible side. We then consult with our clients to determine how we should deal with this. We have noticed that not all customers are fully aware of the possible consequences of scratches in raw aluminium. That is why we would like to provide some more information about this.

If scratches are not removed prior to the powder coating process, they can have a negative effect on the appearance of the applied powder coating. It is even possible that the scratches become more visible through the paint layer, or that they appear as small dots. Deep scratches contain small accumulations of aluminium particles. During heating in the oven, these particles move to the surface, resulting in the formation of these small dots. It is therefore important to thoroughly remove scratches prior to the coating process to ensure an optimal finish.

The powder coating that we apply to the material has a thickness between 60 and 120µm. A human hair is about 80µm, so you can imagine that this layer does not provide any masking against scratches. Our guideline is that scratches will be visible at the moment that they can be felt on the raw aluminum. Only very light scratches will therefore be masked by the powder coating.

It is therefore important to ensure that the aluminium is free of scratches upon delivery. If this is not feasible within your process, removing them by sanding offers an effective solution. This can guarantee an even surface.

Questions or tips to prevent scratches? Feel free to share them below!

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