West System C209SC Extra Slow Hardener, 5.3 L (1.4 Gallon)
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
The West System C209SC 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 preferred choice for large-scale laminating, fairing, and bonding projects where extended open time is essential.
At a 3:1 mix ratio (resin to hardener by volume), the C209SC cures to a clear, amber-coloured solid. This 5.3 L (1.4 Gallon) bulk size is designed for professional shop use and high-volume projects where economy per litre matters. Compatible with the West System 300 Mini Pump for accurate metering.
Note: This product is classified as a hazardous material. Shipping restrictions may apply — please contact us before ordering if you have questions about delivery to your location.
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
- Bulk 5.3 L size for professional and high-volume use
- Compatible with West System 300 Mini Pump for accurate metering
Available Sizes
- West System C209SA Extra Slow Hardener – 315 ml (10.6 oz.) — small size for repairs and single-use projects
- West System C209SB Extra Slow Hardener – 1.24 L (42.2 oz.) — mid-size for larger projects
- West System C209SC Extra Slow Hardener – 5.3 L (1.4 Gallon) — this product
Related Products
- West System C205 Fast Hardener – 3.56 L — faster cure option for cooler conditions
- West System C207SB Special Clear Hardener – 1.24 L — clear finish hardener option
- West System G/Flex 655 Epoxy Adhesive Repair Kit — flexible epoxy repair alternative
Parts Desk Insights
Best Use Case: The C209SC is the right choice for professional boatbuilders, yards, or serious DIYers running large laminating or fairing jobs in warm conditions who want the best cost-per-litre in the C209 Extra Slow family. Always confirm the customer is using West System 105 Resin — this hardener is not a standalone product. Flag the hazmat classification at point of sale — ground shipping only applies and some locations may not be serviceable. For smaller quantities, direct customers to the C209SB (1.24 L) or C209SA (315 ml).
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.