In the MontiPower Two-Step Method, the Tercoo® disc is Step 1. The Bristle Blaster® belt is Step 2. Both run on the same Bristle Blaster® drive unit — with a 30-second changeover between steps. Together they take steel from ISO 8501-1 Grade D corrosion to SSPC-SP10, or to SSPC-SP5 / Sa 3 (white metal) where the coating system demands it, without abrasive blasting.
The Problem Tercoo® Solves
Protective coating systems fail primarily at the interface between coating and steel. When a maintenance engineer encounters a steel structure with heavy corrosion — thick rust layers, laminar scale, areas of deep pitting — they face a preparatory challenge before any surface prep standard can be achieved: the bulk corrosion must come off first.
Wire brushing (SSPC-SP2) removes loose rust and scale but leaves tightly adherent corrosion in place. Angle grinding removes material but burnishes the surface, creating a smooth, hardened profile that reduces coating adhesion. Abrasive blasting is effective but requires grit containment, blast media supply and often cannot be used in operational environments, confined spaces or explosive atmospheres.
Tercoo® fills this gap. It removes heavy corrosion mechanically — faster than wire brushing, without the burnishing effect of grinding, and without the logistics of blasting — leaving the steel surface in a condition where the Bristle Blaster® can achieve SSPC-SP10 in a single subsequent pass.
What Tercoo® Removes
Laminar and layered rust. The primary application. Heavy rust on structural steel, pipelines and marine structures typically builds up in layers — the outer layer is friable and loosely adherent, the inner layer is more tightly bonded but still not the steel substrate. Tercoo® removes both layers without leaving the burnished surface that mechanical grinding produces.
Thick mill scale deposits. On hot-rolled steel that has been stored or exposed without protection, mill scale can accumulate over significant corrosion product. Tercoo® removes this composite layer — scale and rust together — where the Bristle Blaster® alone would be working through too much material to reach the steel surface efficiently.
Deteriorated coating over corroded steel. On maintenance recoating projects where the existing coating has failed and is now sitting over actively corroded steel, Tercoo® removes the failed coating and the corroded layer beneath in a single operation. This is more efficient than first stripping the coating and then treating the rust separately.
Weld spatter and heat-affected oxide. At weld seams on pipeline field joints and structural connections, weld spatter and the oxide scale in the heat-affected zone are mechanically different from the surrounding steel surface. Tercoo® removes these without requiring a separate grinder pass that would leave a smooth, non-adherent surface adjacent to the weld.
Salt-contaminated rust crust. In marine and industrial atmospheric environments, chloride and sulphate salts accumulate within the corrosion product. These salts cause osmotic blistering under new coatings if not removed. Tercoo® removes the contaminated rust mass, reducing the salt load at the steel surface before the Bristle Blaster® pass and any pre-coat salt measurement.
How Tercoo® Works
The Tercoo® disc mounts directly on the Bristle Blaster® drive unit — the same machine used for Step 2. The disc uses flexible SBR material with tungsten carbide pins positioned at a specific angle. When the disc rotates, centrifugal force causes the pins to strike the surface in a controlled pendulum motion — a hammering action that removes paint, bitumen, epoxy, rust and corrosion layers without generating heat. Unlike an angle grinder, which removes material by abrasion and burnishes the steel surface, the pendulum-impact mechanism dislodges corrosion from the substrate interface without work-hardening it. The result is a clean, roughened surface that retains the texture needed for the Bristle Blaster® belt pass to create a consistent anchor profile.
Changeover from the Tercoo® disc to the Bristle Blaster® belt on the same drive unit takes approximately 30 seconds. This single-machine approach reduces equipment investment and simplifies tool inventory on maintenance projects.
Tercoo® Disc Specifications
| Parameter | Specification |
|---|---|
| Drive unit compatibility | Bristle Blaster® Ultimate Electric, Bristle Blaster® Ultimate Cordless, Bristle Blaster® Ultimate Pneumatic Double |
| Disc construction | Flexible SBR disc with tungsten carbide pins at a specific angle for controlled pendulum impact |
| Maximum coating removal thickness | Up to 5 mm |
| Disc service life | Approximately 30 m² per disc pack (Rustgrade B corrosion) |
| Compatible substrates | Steel, concrete, bitumen, rubber |
| Heat generation | None — hammering action only |
| Changeover time (Tercoo® disc → Bristle Blaster® belt) | Approximately 30 seconds |
When to Use Tercoo® vs. Going Directly to Bristle Blaster®
The decision depends on the ISO 8501-1 rust grade of the surface and the nature of the corrosion present:
| Surface Condition | ISO 8501-1 Grade | Approach |
|---|---|---|
| Mill scale, no visible rust | Grade A | Bristle Blaster® directly — no Tercoo® needed |
| Mill scale lifting, rust beginning | Grade B | Bristle Blaster® directly — no Tercoo® needed |
| Mill scale gone, uniform rust, light pitting | Grade C (light) | Bristle Blaster® typically sufficient; use Tercoo® if deposits are present in areas |
| Rust with laminar deposits or scale build-up | Grade C (heavy) / D | Tercoo® Step 1 required before Bristle Blaster® |
| Heavy pitting, thick layered corrosion throughout | Grade D | Two-Step Method required — Tercoo® first, Bristle Blaster® to SP10 |
| Failed coating over corroded steel | Grade C / D under coating | Tercoo® removes coating and rust in one operation; Bristle Blaster® finishes to SP10 |
The practical test in the field: if running the Bristle Blaster® over the surface produces an inconsistent profile or the wire tips are visibly rolling over loose material rather than impacting steel, Tercoo® is needed first.
What Tercoo® Does Not Do
The Tercoo® disc removes the corrosion mass and leaves a clean, roughened substrate. It does not, on its own, achieve a measured surface preparation standard such as SSPC-SP10 or SSPC-SP5, and does not create the 65–85 µm Rz anchor profile required for high-performance coating systems. After the Tercoo® disc pass, the substrate is clear of bulk corrosion and old coating — ready for the Bristle Blaster® belt — but not yet at a verified cleanliness or profile standard. The Bristle Blaster® Step 2 is required to achieve the SP10 or SP5 / Sa 3 standard and the anchor profile specification.
This distinction matters for quality documentation: the Tercoo® step is preparation, not the measurable standard. The SP10 documentation — visual comparison against SSPC-VIS 1, Testex replica tape profile measurement, soluble salt reading — is taken after the Bristle Blaster® pass, not after the Tercoo® disc pass.
Applications
| Industry | Application | Why Tercoo® |
|---|---|---|
| Oil & Gas / Pipeline | Field joint rehabilitation; in-service pipeline maintenance | ATEX environments prohibit blasting; remote locations have no blast facilities; field joints are often Grade D after years in service |
| Offshore Structures | Jacket legs, deck plating, structural connections in splash zone | Marine corrosion in splash zone produces Grade C/D surfaces; blasting offshore requires extensive containment; Tercoo® + Bristle Blaster® operates without grit |
| Infrastructure | Bridges, industrial buildings, port structures, overhead gantries | Traffic management or operational constraints prevent blast shutdowns; Tercoo® works within normal maintenance windows |
| Petrochemical / Refinery | Vessel external maintenance, pipe rack steelwork, structural members | ATEX Zone 1 and Zone 2 areas require spark-controlled, grit-free tools; Tercoo® + pneumatic Bristle Blaster® are ATEX-certified for Zone 1 |
| Marine / Shipyard | Hull section repairs, tank structural maintenance, deck steelwork | Localised maintenance between dry dock cycles; Tercoo® allows spot treatment of Grade D areas without full blast mobilisation |
Frequently Asked Questions
Does Tercoo® achieve any formal surface preparation standard on its own?
No — and this is by design. Tercoo® is the pre-treatment step, not the standard-achieving step. Its output is cleared steel ready for the Bristle Blaster®. The Two-Step process as a whole achieves SSPC-SP10 / Sa 2½. Attempting to verify a formal standard after the Tercoo® pass alone would not reflect the final surface condition — verification is performed after the Bristle Blaster® pass.
Can the Tercoo® disc be used in ATEX Zone 1 environments?
The Tercoo® disc mounts on the Bristle Blaster® drive unit. For ATEX Zone 1 classified environments, the relevant certification is that of the drive unit. The Bristle Blaster® Ultimate Pneumatic carries confirmed ATEX Zone 1 certification (Ex II 2G c IIA T4 X). For specific confirmation of whether the Tercoo® disc and Bristle Blaster® drive unit combination is approved for Zone 1 deployment in your project context, contact the MontiPower technical team directly — do not assume certification applies without direct verification against your project’s area classification documents.
How does Tercoo® compare to angle grinding for heavy rust removal?
Angle grinding removes material faster on very thick deposits, but it leaves a smooth, burnished surface that reduces coating adhesion — the grinding action work-hardens the steel surface and eliminates the natural micro-texture. Additionally, angle grinding cannot be used in ATEX Zone 1 environments due to spark risk. Tercoo® is slower on the thickest deposits but preserves the surface texture needed for the subsequent Bristle Blaster® pass to create a proper anchor profile. The Two-Step result — SP10 cleanliness with 65–85 µm Rz profile — cannot be achieved reliably if angle grinding is used in Step 1.
Is Tercoo® suitable for use on thin-walled or corroded pipe where aggressive tooling could cause perforation?
Tercoo® should not be used on pipe walls where corrosion has reduced wall thickness to near the minimum tolerable level — the mechanical action of any power tool on severely degraded thin-wall pipe carries a risk of perforation. In these situations, ultrasonic wall thickness measurement should precede any mechanical treatment, and the project engineer should assess whether the asset is suitable for in-service surface preparation or requires replacement.
Ask about Tercoo®
MontiPower technical team — tool selection, application guidance and the Two-Step Method for heavy corrosion in your specific environment.