What is Shot Blasting?
Shot blasting is a critical process that removes mill scale from steel surfaces, ensuring a clean and uniform finish.
Mill scale, a type of iron oxide formed during the hot rolling process, appears as a smooth, bluish-grey layer. While it might seem protective, mill scale is neither uniformly adhered nor durable. Left untreated, it can cause significant issues, such as:
- Coating Failure: Paint applied over mill scale often cracks and detaches, leaving the steel surface exposed.
- Accelerated Corrosion: The porous nature of mill scale allows moisture to penetrate, triggering galvanic reactions that lead to pitting corrosion.
- Structural Damage: Rust growth beneath the mill scale exacerbates cracking and spreads corrosion further.
To prevent these problems, mill scale must be completely removed to achieve a clean surface, ensuring optimal adhesion and longevity for protective coatings.
Our Process at Bluewater Boats
At Bluewater Boats, we clean steel surfaces to an SA 2.5 profile using an abrasive blast. This process removes mill scale entirely and creates the necessary surface profile for the paint system to adhere effectively. Painting over mill scale, however tempting, is a short-term solution that accelerates corrosion and compromises the integrity of the steel.
Real-World Example: The Importance of Shot Blasting
We recently restored a narrowboat that had been painted without removing mill scale. Less than a year after its launch, the boat suffered significant rust damage both above and below the waterline. The owner brought it to us for shot blasting and repainting, and the results speak for themselves—a durable and professional finish that will stand the test of time.
Two-Pack Paint Systems: Superior Protection
Underwater Areas: Two-Pack Epoxy Blacking
After shot blasting to SA 2.5, we apply Interzone 954, a premium two-pack epoxy blacking developed by International Paint. This high-performance coating is widely used on offshore installations due to its exceptional durability.
Benefits of Interzone 954:
- Hardwearing Blacking: Ideal for underwater areas.
- 7-Year Guarantee: Proven longevity and performance.
- Localized Protection: Scratches do not spread due to the indentation of the blast profile, unlike conventional paints.
Above Waterline: Two-Pack Paint System
For cabin sides, roofs, and deck areas, we apply a comprehensive two-pack paint system, including:
- Epoxy Primer: High-build, high-performance primer for superior adhesion.
- Finishing Primer: Enhances durability and surface preparation.
- Polyurethane Undercoats: Adds strength and resilience.
- Top Coats: Provides a high-gloss, abrasion-resistant finish in a wide range of colours.
- Non-Slip Coatings: Ensures safety in high-traffic areas.
Top Coats: Premium Finishes
We offer two premium two-pack topcoat systems, ensuring exceptional durability and visual appeal:
- Two-Pack Polyurethane (International Paints):
- Ultra-high gloss with excellent colour retention.
- Abrasion-resistant, ideal for high-wear areas like bollards and fender zones.
- UV protection to prevent premature ageing.
- Exceptional durability, ensuring your boat maintains its striking finish for years.
- Two-Pack Acrylic Urethane (Awlgrip by Marineware):
- Fast-drying with long-lasting gloss and colour retention.
- Buffable finish, allowing minor scratches to be polished out.
- Available in metallic colours for a bespoke, luxurious appearance.
Why Choose Bluewater Boats?
Our two-pack paint systems are trusted by leading superyacht builders like Sunseeker and Princess Yachts, ensuring a premium finish that makes your boat the envy of your peers. Whether for durability or aesthetic excellence, our shot blasting and painting services guarantee the highest standards.
For more information or to see the transformation of our latest projects, contact us today. Let Bluewater Boats provide the professional finish your vessel deserves.
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