Belzona 5841
CUI Protection
An epoxy coating requiring minimal surface preparation for in-situ repair and protection of hot metal surfaces subject to corrosion under insulation.
A 100% solids, 2-part epoxy coating designed to provide outstanding protection to hot metal surfaces against corrosion under insulation (CUI). This surface-tolerant coating can be applied by brush directly onto hot metal surfaces from 30°C to 80°C (86°F - 176°F) with minimal surface preparation required.
- SeriesBelzona 5000 Series
- Documents3
Overview of Belzona 5841
A 100% solids, 2-part epoxy coating designed to provide outstanding protection to hot metal surfaces against corrosion under insulation (CUI). This surface-tolerant coating can be applied by brush directly onto hot metal surfaces from 30°C to 80°C (86°F - 176°F) with minimal surface preparation required.
Key Benefits
Outstanding performance under elevated temperature conditions including dry heat and steam exposure
No solvents, no shrinkage during cure
Bonds tenaciously even when surface preparation is minimal or substrate is contaminated
Outstanding resistance to corrosion in salt spray and chemical environments
Application Areas
What this product handles, grouped by equipment area — each links to the full application.
Tanks & Chemical Containment Areas
3 applications- External pipe & tank corrosion protectionCoating of pipelines prone to corrosion damageLearn more
- Corrosion under insulation (CUI) preventionPrevention of corrosion under insulation (CUI)Learn more
- Hot vessel in-situ external coatingIn-situ external coating of process vessels during service operating at high temperature avoiding production downtimeLearn more
Technical Data
Performance Characteristics
- Hot surface application
- Applied directly on hot metal from 30°C to 80°C (86°F to 176°F)
- Excellent CUI protection for surfaces operating up to 80°C (176°F)
- Fast cure on hot surfaces allowing rapid re-insulation
- Compatible with Belzona 5851 (HA-Barrier) in overlap areas
- Refer to the attached Product Specification Sheet for full mechanical and chemical data
Cure Times on Hot Surfaces
At 60°C (140°F)
- Touch dry
- 1 - 2 hours
- Overcoat window
- 4 - 24 hours
- Full cure
- 24 hours
At 80°C (176°F)
- Touch dry
- 30 - 60 minutes
- Full cure
- 12 hours
Service Temperature Limits
- Application substrate temperature range
- 30°C to 80°C (86°F to 176°F)
- Continuous dry service temperature
- Up to 80°C (176°F)
- For hotter substrates (up to 150°C / 302°F)
- Use Belzona 5851 (HA-Barrier)
Mixing & Application
Product PDFs
Gallery
Videos
Frequently Asked Questions
What is corrosion under insulation (CUI) and how does Belzona 5841 prevent it?
Corrosion under insulation occurs when moisture becomes trapped under thermal insulation, accelerating corrosion of the underlying metal. Belzona 5841 forms a 100% solids epoxy barrier directly on hot metal surfaces (30-80°C / 86-176°F) before insulation is applied, blocking the moisture contact that drives CUI.
Does the equipment need to be shut down to apply Belzona 5841?
No. Belzona 5841 is designed for in-situ application by brush on live equipment operating at high temperatures with minimal surface preparation. This avoids costly production downtime.
Up to what temperature can Belzona 5841 be applied?
Belzona 5841 can be applied directly onto hot metal surfaces from 30°C to 80°C (86°F - 176°F). For surfaces hotter than 80°C, the heat-activated Belzona 5851 (HA-Barrier) is suitable up to 150°C (302°F).
Related Products
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