THE FINISHING PROCESS
Our highly trained technical team operate from an advanced production facility to ensure that the latest galvanizing standards are met, and that our customers enjoy a high quality, resilient finish. Galvanizing can result in a 40-year lifespan and significantly enhanced resistance to corrosion (dependent on environment or industrial factors) – benefits too good to pass up on, if you ask us.
STEP 1: Preparation
Any one of our team will tell you that a disciplined and attentive preparation process is key to achieving a high-quality finish. We begin by pre-treating the steel with a hot alkaline de-greasing solution to remove any oil-based contamination. This is followed by a hydrochloric acid treatment, which removes surface oxidisation and mill scale. When the treatment has been applied for a certain time, the steel is rinsed in water.
STEP 2: Flux
The steel – which we refer to as “the work” – is now immersed in a heated preflux. This process aids the wetting of the work and flow of zinc, which is critical to achieving a smooth finish later down the line. The flux is heated to reduce thermal shock and improve immersion times.
STEP 3: Zinc Bath
The work is then submerged into a bath of molten zinc, which is heated to 445 degrees. Here, the zinc becomes an integral part of the steel.
STEP 4: Passivation
Here, we reach the final step of the galvanizing process within our finishing process. This is passivation, which will prevent wet storage stain – otherwise known as white rust. Passivation also helps to maintain a bright and polished appearance.
STEP 5: Fettle
To achieve a smooth surface for powder coating, we undertake a process called “fettling”. This eradicates rough edges and uneven surfaces to prepare the work for a smooth powder coated finish.
STEP 6: Powder coating pretreatment
Now, we take specific preparatory steps for powder coating. These include passing the work through several intensive treatments.
STEP 7: Spray booth
Using electrostatic charge, one of 180 European RAL colours powders is sprayed onto the surface of the work. Our customers can choose the colour they’d like. An even and consistent finish is achieved by applying the perfect amount of pressure and powder, tried and tested from experience. Barkers is keen to fly the eco flag wherever we can and are conscious of our environmental impact. So, you won’t find any worrying solvents in our powders and recycle up to 80% of unused powder by passing it back through the system to reduce waste, too.
STEP 8: Cured
Finally, we cure the work in a specialist industrial oven at a heat of 180 degrees for a period of 10 to 12 minutes. Under this intensive heat, the powder fuses and melts resulting in a hard and durable film coating the entire product.