ALKA-9930
Premium External Protective Coating System
Premium three-coat corrosion protection system for exposed structural steel requiring long-term durability, high-performance barrier protection and a UV-stable architectural finish.
Premium Long-Term Protection for Exposed Structural Steel
ALKA-9930 is a premium three-coat protective coating system developed for abrasive-blasted carbon steel exposed to external atmospheric environments where long-term corrosion protection, durability and appearance are all important.
Rather than relying on a single coating technology, ALKA-9930 combines three complementary protective mechanisms: a zinc-rich epoxy primer, a high-build epoxy barrier coat, and a UV-resistant polyurethane finish.
The system begins with ALKA-404 Zinc-Rich Epoxy Primer, providing the primary corrosion-protection layer directly over prepared steel. This is followed by ALKA-413 High-Build Epoxy, which substantially increases the protective barrier between the steel and the surrounding environment. The system is completed with ALKA-421 Polyurethane Finish, providing the exposed surface with weathering resistance, colour retention and a durable architectural finish.
ALKA-9930 is therefore intended for important external steel assets where a basic industrial primer-and-topcoat system would not provide the desired level of protection or long-term appearance.
PROTECTION STRATEGY
ALKA-9930 uses a Primer + Barrier + Weathering Finish approach.
Each coat has a different role in the overall corrosion-control strategy:
Zinc-Rich Epoxy Primer
Provides the first line of corrosion protection directly at the prepared steel surface.
High-Build Epoxy Barrier
Creates substantial film thickness and isolates the substrate from atmospheric moisture and contaminants.
Polyurethane Finish
Protects the epoxy system from external weathering and provides the final colour, gloss and appearance.
This layered approach makes ALKA-9930 particularly suitable for high-value assets where coating failure would result in expensive access, shutdown, maintenance or recoating.
KEY PERFORMANCE BENEFITS
- Premium three-coat corrosion-protection system
- Designed specifically for externally exposed carbon steel
- Zinc-rich epoxy primary corrosion protection
- High-build epoxy barrier protection
- UV-resistant polyurethane exterior finish
- Excellent colour and appearance retention
- Suitable for demanding industrial atmospheric exposure
- Suitable for coastal atmospheric environments
- High total protective film build
- Durable finish for visible structural steel
- Suitable for new construction and major refurbishment where full surface preparation is possible
- Reduces reliance on frequent maintenance compared with basic coating specifications
- Suitable for high-value and difficult-to-access steel assets
- Professional finish for architectural and infrastructure projects
- Compatible coating technologies designed to perform as an integrated system
SYSTEM BUILD-UP
Substrate — Abrasive-Blasted Carbon Steel
ALKA-9930 is intended primarily for carbon steel that can be properly abrasive blasted before coating.
The steel surface must be clean, dry and appropriately prepared to remove mill scale, corrosion products, contamination and other materials capable of compromising coating adhesion or corrosion performance.
Surface preparation is not simply a preliminary operation in this system; it is an integral part of the corrosion-protection specification.
COAT 1 — ALKA-404 Zinc-Rich Epoxy Primer
Function: Primary corrosion-protection primer
ALKA-404 is applied directly to the prepared steel substrate and forms the foundation of the ALKA-9930 system.
Its purpose is to establish a high-performance zinc-rich epoxy primer layer at the steel/coating interface before the high-build barrier coats are applied.
This layer is particularly important in a premium external system because deterioration of the coating system ultimately begins at the steel interface.
Product: ALKA-404 Zinc-Rich Epoxy Primer
Position: Directly over prepared carbon steel
Primary Function: Corrosion-protection primer
Nominal DFT: To project specification / current ALKA TDS
COAT 2 — ALKA-413 High-Build Epoxy
Function: High-build intermediate barrier coat
ALKA-413 forms the principal barrier layer of ALKA-9930.
The high-build epoxy intermediate coat increases the total protective film thickness and creates a substantial physical barrier between the primed steel substrate and the external environment.
Its role is particularly important where the asset is exposed to industrial atmospheric contaminants, moisture and demanding external service conditions.
The intermediate coat also provides the transition between the zinc-rich primer and the final polyurethane weathering coat.
Product: ALKA-413 High-Build Epoxy
Position: Intermediate coat
Primary Function: High-build barrier protection
Nominal DFT: To project specification / current ALKA TDS
COAT 3 — ALKA-421 Polyurethane Finish
Function: UV-resistant weathering and appearance coat
ALKA-421 forms the final exposed surface of the system.
Epoxy coatings provide excellent barrier properties but are not normally selected as the final exposed coating where long-term colour and appearance under sunlight are important.
ALKA-421 therefore completes the system by providing a durable polyurethane exterior finish with improved resistance to UV exposure and weathering while delivering the specified final colour and appearance.
Product: ALKA-421 Polyurethane Finish
Position: Final exposed coat
Primary Function: UV resistance, weathering protection and appearance
Nominal DFT: To project specification / current ALKA TDS
Nominal Total System DFT: 250–300 μm
Final individual coat thicknesses and total system DFT must be confirmed against the current ALKA product technical data sheets and project specification.
SUITABLE SUBSTRATES
ALKA-9930 is primarily intended for:
Abrasive-Blasted Carbon Steel
Typical fabricated steel components include structural sections, plate steel, fabricated frames, columns, beams, pipe supports, steel tanks and other externally exposed carbon-steel assets.
Other substrates should not automatically be assumed suitable for the same build. Galvanised steel, aluminium, stainless steel or previously coated surfaces require separate assessment and potentially a different surface preparation and primer selection.
SERVICE & EXPOSURE ENVIRONMENT
ALKA-9930 is intended principally for external atmospheric corrosion protection.
Suitable environments include:
- Industrial atmospheric exposure
- Coastal atmospheric exposure
- External weather exposure
- High-humidity industrial locations
- Steel exposed to rain and condensation
- Outdoor process facilities
- Externally exposed infrastructure
- Locations where UV exposure makes an epoxy-only finish undesirable
ALKA-9930 should be distinguished from specialist immersion, chemical-lining, splash-zone or tidal-zone systems. Those applications require systems specifically selected for those exposure conditions.
TYPICAL APPLICATIONS
Bridges & Transport Infrastructure
Structural beams, cross-members, support structures and exposed steel components.
Industrial Pipe Racks
Carbon-steel pipe racks, support frames, columns and associated structures.
Refineries & Petrochemical Facilities
External platforms, equipment supports, access structures and atmospheric steelwork.
Tank Exteriors
External surfaces of steel storage tanks exposed to weather and sunlight.
Mining & Materials-Handling Infrastructure
Conveyor structures, processing-plant steelwork, transfer structures and equipment supports.
Ports & Coastal Infrastructure
Above-water steelwork exposed to salt-laden coastal atmosphere but outside splash, tidal and immersion zones.
Architecturally Exposed Structural Steel
Visible steelwork where corrosion protection and long-term finished appearance are equally important.
SURFACE PREPARATION
Correct surface preparation is critical. Steel should be abrasive blasted to the preparation standard and surface profile specified for the project.
Oil, grease, rust, mill scale, dust, soluble contamination, weld spatter and surface defects must be appropriately addressed. Edges, welds, bolts and difficult geometries should receive suitable preparation and stripe coating where specified.
APPLICATION & QUALITY CONTROL
Application conditions including ambient temperature, steel temperature, relative humidity and dew point must be monitored.
Mixing, pot life, wet-film thickness, dry-film thickness, recoat intervals and curing requirements must comply with the relevant product technical data.
Inspection should include surface preparation, environmental conditions, stripe-coated areas, individual coat DFT and final system DFT.
LIMITATIONS
ALKA-9930 is primarily an atmospheric system and should not automatically be specified for continuous immersion, internal tank lining, chemical containment, buried steel or severe splash/tidal exposure.
SPECIFICATION GUIDANCE
A complete project specification should define:
Substrate → Surface Preparation → Surface Profile → ALKA-404 → ALKA-413 → ALKA-421 → Individual Coat DFT → Total DFT → Stripe Coating → Colour/Gloss → Environmental Limits → Inspection & Acceptance Criteria
Application Examples
External atmospheric protection for exposed steel structures.
Bridges & Infrastructure
Industrial Pipe Racks
Tank Exteriors
Photographic visuals on this page are AI-generated application illustrations, not completed ALKA projects. Colours are illustrative. The system schematic is conceptual and not to scale; refer to current ALKA technical data and project specifications.