Case Study: Transforming Public Transport Buses with Garnet Blasting

Fleet Renewal

Public transport buses endure harsh conditions every day. They face road debris, changing weather, and constant passenger traffic. Over time, old paint and rust can develop. This affects the vehicles’ appearance and can lead to structural concerns if not addressed. AA Sandblasting, founded in 1977 worked on a major fleet renewal project. This case study details how garnet blasting helped return multiple buses to good condition.

Project Overview

A regional transport authority contacted AA Sandblasting about refurbishing its ageing bus fleet. The buses still functioned mechanically, but their exteriors suffered from faded paint, corrosion, and accumulated grime. The goal was to create a professional look and protect the metal surfaces.

Objectives

1. Remove Old Coatings and Rust
   Stripping away failing layers of paint and oxidised metal was critical.

2. Prepare Surfaces for Repainting
   Fresh paint requires a clean surface with the correct profile.

3. Minimise Downtime
   The authority needed the buses back on the road quickly to meet service demands.

Why Choose Garnet?

Garnet is a hard, naturally occurring mineral with characteristics that make it well suited for this project:

1. Efficient Removal of Coatings
   The sharp edges of garnet help it slice through thick paint and corrosion.

2. Consistent Surface Profile
   Garnet blasting can leave an even texture without gouging metal panels. This ensures the primer and paint can bond well.

3. Reduced Dust Compared to Some Abrasives
   While all blasting produces dust, garnet tends to break down less. This helped maintain clear visibility in the workspace.

Step-by-Step Process

1. Assessment and Planning

Each bus was inspected to identify rust-prone sections and determine how many coats of paint needed removing. This guided the choice of blast pressure and nozzle type.

2. Containment Setup

We prepared enclosed blasting bays to limit dust and debris escape. This also helped us gather and recycle garnet media. Operators wore protective suits, respirators, and gloves. Containment measures ensured bystanders and nearby staff remained safe.

3. Garnet Blasting in Action

The blast process began with areas of heavy rust or flaking paint. Our operators used controlled pressure to remove all failing coatings without distorting thinner metal panels. The air and garnet mix effectively cleaned wheel arches, side panels, and bus roofs.

• Side Panels
  The large, flat sides often had multiple layers of old paint. Garnet cut through these layers, leaving bare metal ready for coating.

• Wheel Arches
  Road salt and debris collect here, accelerating corrosion. Garnet quickly tackled rust pockets and chipped paint.

• Roof Sections
  These areas can accumulate grime from air pollutants. Blasting restored the surface to a consistent, workable finish.

4. Cleanup and Inspection

Any remaining dust or abrasive was cleaned away using vacuum systems and gentle brushing where needed. We then checked the surface for leftover rust or paint. Detecting and correcting missed spots at this stage saves time and prevents coating failures later.

5. Primer and Paint Application

Although AA Sandblasting focuses on blasting services, we coordinated with the paint team. They applied primer quickly to stop flash rust from forming. A specialised topcoat followed, designed to handle weather and regular washing routines.

Project Outcome

1. Enhanced Appearance
   The refurbished buses showed a clean, uniform exterior. This uplifted the public perception of the transport authority’s fleet.

2. Prolonged Service Life
   Removing rust and applying durable coatings can extend the life of these vehicles. The metal panels now have a barrier against corrosion.

3. Efficient Turnaround
   Careful planning allowed multiple buses to be cycled through the blasting process without delaying the authority’s operations.

4. Improved Worker Safety
   Garnet’s relatively low dust output, combined with proper ventilation and PPE, maintained a safe work environment for our team.

Lessons and Recommendations

• Plan for Surface Thickness Variations
  Buses often have both thin panels and thicker structural parts. Adjusting blast pressure preserves delicate sections while thoroughly removing rust.

• Prioritise Containment
  Enclosing the workspace and using correct ventilation keeps dust to a minimum. It also streamlines media recycling.

• Inspect Midway
  Mid-blast checks reveal hidden corrosion and ensure the operator modifies their approach, if needed.

• Coating Coordination
  Establishing a tight schedule with the painting team prevents uncoated metal from sitting in humid air, reducing the risk of flash rust.

Conclusion

Garnet blasting proved effective for transforming a large fleet of public transport buses. By quickly cutting through old paint and rust, it prepared the exteriors for new coatings. AA Sandblasting’s structured approach balanced efficiency with the need for thorough cleaning. The result was a set of vehicles returned to service looking sharp, with a longer protective lifespan. If your project requires similar large-scale surface restoration, garnet blasting can deliver the performance and durability you need.