West System C209SB Extra Slow Hardener, 1.24 L (42.2oz.)
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The West System C209SB Extra Slow Hardener is designed for use with West System 105 Epoxy Resin in hot, humid, or high-temperature conditions where standard hardeners cure too quickly. It provides approximately twice the working time of the 206 Slow Hardener, making it the right choice for large laminating projects, complex assemblies, or any application where extended open time is critical.
At a 3:1 mix ratio (resin to hardener by volume), the C209SB cures to a clear, amber-coloured solid. It is compatible with the West System 300 Mini Pump for accurate metering. This 1.24 L (42.2 oz.) size is well-suited for mid-size projects and professional shop use.
Cure Schedule
- Pot life: 15–20 minutes at 95°F (35°C) / 50–60 minutes at 70°F (21°C)
- Solid state: 6–8 hours at 95°F / 20–24 hours at 70°F
- Full cure: 4–9 days additional curing after solid state
- Maximum pot life: adequate up to 110°F (43°C)
Key Features
- Extra slow cure for hot, humid, or high-temperature conditions
- Approximately 2× the working time of 206 Slow Hardener
- Mix ratio: 3:1 (resin to hardener by volume)
- Cures to a clear, amber-coloured solid
- Compatible with West System 300 Mini Pump for accurate metering
Available Sizes
- West System C209SA Extra Slow Hardener – 315 ml (10.6 oz.) — smaller size for smaller projects
- West System C209SB Extra Slow Hardener – 1.24 L (42.2 oz.) — this product
- West System C209SC Extra Slow Hardener – 5.3 L (1.4 Gallon) — bulk size for large projects
Related Products
- West System C205 Fast Hardener – 814 ml — faster cure option for cooler conditions
- West System C207SB Special Clear Hardener – 1.24 L — clear finish option
- West System 306 Large Capacity Metering Pump — for accurate dispensing on larger volumes
Parts Desk Insights
Best Use Case: Recommend the C209SB when a customer is working in warm or humid conditions (summer boatyard work, tropical climates, or heated shops) and needs maximum working time for large laminating, fairing, or bonding jobs. It’s the go-to hardener for complex multi-step assemblies where the standard 206 Slow Hardener doesn’t provide enough open time. Always confirm the customer is using West System 105 Resin — this hardener is not a standalone product. If they need a smaller quantity for a one-off repair, direct them to the C209SA (315 ml). For bulk shop use, the C209SC (5.3 L) is more economical.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.