Jotun Jotamastic 90 2 Pack 5L - Off White

Note  This item can only ship within Ireland 

Jotamastic 90 is a two-component, polyamine-cured, high-solids epoxy mastic coating developed by Jotun for corrosion protection in maintenance and new construction. It is one of the company's flagship surface-tolerant coatings and is widely specified in offshore, marine, industrial, power generation, and infrastructure applications. It is designed to perform even where abrasive blast cleaning to bare steel is impractical.

Brief Summary

Jotamastic 90 is a high-solids, surface-tolerant epoxy mastic primer with 80% volume solids and a recommended 100–300 μm dry film thickness per coat. It is designed for demanding maintenance and new-build corrosion protection, offering excellent adhesion to marginally prepared steel, strong abrasion resistance, compatibility with a range of substrates, and suitability for both atmospheric and immersed service. Its versatility and proven durability have made it a widely specified coating in marine, offshore, and heavy industrial sectors

Typical Applications

• Structural steel
• Offshore platforms
• Marine vessels
• Ballast and immersed structures
• Bridges
• Pipelines
• Tanks
• Industrial plants
• Maintenance painting over aged coatings

Suitable for:

• Carbon steel
• Galvanized steel
• Stainless steel
• Aluminium
• Concrete
• Properly prepared existing coatings

Technical Specifications

Recommended Film Thickness

Higher film builds can be achieved depending on the specification and application method.

Key Performance Features

• Surface-tolerant coating suitable over mechanically prepared steel.
• Excellent corrosion protection in high-corrosivity environments.
• High abrasion resistance.
• Suitable for immersion and atmospheric exposure.
• Can function as:
  • Primer
  • Intermediate coat
  • Finish coat
  • Single-coat system
• Short overcoating intervals.
• Can be applied at sub-zero surface temperatures (Winter Grade available).
• Long service life in harsh industrial and offshore environments.

Surface Preparation

Recommended preparation includes:

• Abrasive blast cleaning where possible (e.g., Sa 2½).
• Power tool cleaning to St 2 or St 3 for maintenance work.
• Remove oil, grease, salts, loose rust, and contaminants.
• Existing coatings must be sound and well adhered.

One of the strengths of Jotamastic 90 is its ability to tolerate less-than-ideal surface preparation compared with conventional epoxy primers.

Application Methods

Suitable for:

• Airless spray (preferred)
• Brush (stripe coating and small areas)
• Roller (limited applications)

High-pressure airless spray is typically recommended for achieving the specified dry film thickness efficiently.

Environmental Resistance

Designed for:

• C5 high-corrosivity atmospheric environments
• Offshore splash zones
• Marine exposure
• Industrial chemical atmospheres
• Immersion service (in approved systems)

The coating provides excellent resistance to:

• Water
• Salt spray
• Abrasion
• Weathering (when top-coated)
• Industrial pollutants

Certifications and Standards

Jotamastic 90 is available in systems that are:

• Pre-qualified to NORSOK M-501 (selected systems)
• Certified to IMO PSPC (Resolution 288(87)) for crude oil tanks
• Tested for LEED®
• Tested for BREEAM® environmental credits

Advantages

• Excellent adhesion to aged coatings
• High-build coating reduces the number of coats required
• Performs well where blasting is difficult or impossible
• Suitable for maintenance shutdowns
• Long-term corrosion protection
• Tintable to a wide range of colours
• Proven performance with decades of field use

Typical Coating Systems

A common heavy-duty atmospheric system is:

1. Surface preparation (Sa 2½ or St 3)
2. Jotamastic 90 (150–250 μm DFT)
3. Optional second coat of Jotamastic 90
4. Polyurethane topcoat (e.g., Hardtop XP) where UV colour and gloss retention are required

Because epoxy coatings chalk under prolonged UV exposure, a polyurethane finish coat is generally recommended for exterior applications where appearance is important.