What Causes Powder Coating to Fail?

When powder coated metalwork has been exposed to weather and other environmental conditions, it can begin to fail.

We look at the causes and signs which allow powder coating to fail and failure.

We must look at what powder coatings are first and how it works to be able to offer advice on the failings.

What is Powder Coating?

Powder coating is a method of coating metalwork and other substrates.

A mixture for the powder coating is usually purchased from a coating company.

The mixture is normally a polymer resin system consisting of pigment, curing solution, levelling agent, flow modifiers and additional additives.

The mixture is heated, cooled and normally applied to the surface of objects by an electrostatic spray gun before being sent to an oven to cure at high temperatures.

This process ensures that molecules in the coating react and make long-chain molecules.

These types of molecules are hard to break down and this is why Powder Coating is an excellent form of protection when it comes to coating surfaces.

Advantages of Powder Coating

  • Very durable and hard-wearing. Preferred over liquid coating for this reason
  • Environmentally friendly
  • Can be applied in almost any colour.
  • Can carry out large batches in one setting

Common Powder Coated Items

  • Household Appliances- Refrigerators, washers, dryers etc
  • Automotive industry- lots of vehicle parts including hubcaps, bumpers, wheels etc
  • Architectural Items- Building parts such as doors, windows, fencing etc

Why Does Powder Coating Fail?

Powder Coating Cracking

Cracking of powder coating usually occurs when the temperature hasn’t cured enough in the factory before being sent out.

The main solution is placing the items back in the oven and allowing the appropriate curing time and conditions.

Powder Coating Peeling

Powder Coating may start to flake or peel off if the surface preparation of the metalwork wasn’t carried out correctly before the powder coating started.

Powder Coated Tough go into greater detail on this.

Contaminants of the surface can cause a reaction and this, in turn, causes a lack of coating adhesion.

There are multiple reasons why powder coating can fail prematurely from the factory setting.

Too much moisture, inadequate charge, powder to fine and lots more are all examples of this.

Wear & Tear

Break down will occur in all coating, even factory cured powder coating. Impact over time will breakdown the coating, objects that people carry like keys and jewellery.

Powder Coating Breakdown  on Staircase

Chalking is the first stage of the natural breakdown of the coating.

If you experience this happening it is advised to carry out maintenance.

Typical items exposed in high impact areas are entrance doors and handles, staircase handrails and other handrails

What is the solution?

If the powder coating has already failed then the best advice is to re-coat.

Either on-site or remove if possible for re-coating in a factory environment.

Failure and the subsequent corrosion of the bare metal will only worsen.

Look for professional powder coating companies or specialist on-site coating contractors who can paint over the powder coat finish.

These companies can provide the best advice and support regarding getting your objects to a brand new finish.

The company should give you advice on how to re-coat the finish along with a comprehensive quote.

Conclusion

A Powder coat finish, when correctly applied under ideal conditions, will provide the most durable finish available.

It will break down over time and you should get treatment as soon as this is recognised to prevent costly repairs later in the corrosion cycle.