Powder coating provides a durable finish to materials used in a broad range of industries, but can you paint over it?
Despite its sturdiness, over time powder-coated material may suffer abrasions or other damage.
Or you may simply want to refresh its appearance.
However, to paint over powder coating requires the right kind of preparation and choice of materials.
To understand how best to paint over powder coating, it makes sense to first understand what it is made of.
Powder coating is an alternative to liquid paint and comes in the form of a dried powder.
As a paint finish, it is perfect for metals such as aluminium and galvanised steel while also adhering to various other substrate surfaces.
Powder coating is a compound consisting of specialised resins, fillers and pigments, including thermosetting polyester, epoxy and epoxy-polyester.
You apply it using a low-velocity, air-powered spray gun.
Once applied, the curing process fuses the various elements in the coating together to create a painted finish.
Powder coating creates a smooth, flat finish.
That is challenging when applying liquid paint because it will struggle to bind properly to powder-coated surfaces.
Another issue is performance. Powder coating is a high-performance paint solution that offers lasting resistance to wear and tear, scratches, abrasions and weather conditions.
If the material you intend to use to paint over powder coating does not meet similar standards, then it will fail to match the powder coating’s performance.
Therefore if you want to paint over a powder coating you must approach the task with careful preparation.
The following Guide is for small parts – should you require a large area to be recoated then this will require a specialist on-site coating applicator please contact us for more details
First, clear the surface you intend to paint over.
You must clean off all dirt, debris and grease. Remove any loose material with a brush.
Next, consider how you can make sure your new paint will adhere to the surface.
Use a fine grade abrasive paper. Normally, powder coating has a slick surface which does not allow paint to stick. Sanding it down carefully will enable you to paint on it effectively.
Wipe down the area you will be painting with an appropriate solvent cleaner.
Finally, rinse it down with warm water, then allow it to dry.
The first thing you must apply is a primer, and one which will work with whatever material your surface is made of. Different primers will be best suited to either aluminium or steel, for example.
A primer also allows you to test for adhesion.
Apply a small spot of primer first. Wait 20 to 30 minutes and then try and wipe it off. If it wipes off easily, smears or smudges, this means there is not enough adhesion between the paint and the surface.
If the spot is stable, then you can proceed in coating the entire surface you wish to paint over with the primer.
Once the primer is dry, you can apply the paint.
It is important to choose the right kind for the task.
Epoxy-based products will stick to most surfaces, but enamel paints are likely to be more cost-effective.
They also adhere well to primers most suited to metal alloy surfaces.
When you apply your paint, consider what coating will be right for your product and what kind of finish you are looking to achieve.
You are going to need a couple of coats. Drying time between coats, and after you have finished painting, will depend on the type of paint and nature of the surface you are applying it to.
While it is perfectly possible to paint over powder coatings successfully, you should also consider:
How intact the powder coated surface is; where significant parts of it are missing, the best option might be to remove all remaining coating first by sandblasting it
If there is any rust present; again, sandblasting can be a preferable option if the degree of oxidation is high
Adequate preparation of the surface is the key to success when painting over it.
If you prepare properly, then there is no reason why you cannot paint over a powder coating.
For more information about powder coatings, please contact Tomburn.