Sudbury 350 Marine Penetrating Sealant
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
Sudbury 350 – Marine Penetrating Sealant
Sudbury 350 is a low-viscosity marine penetrating sealant specifically formulated to flow into narrow seams, fine joints, and tight gaps that standard cartridge sealants cannot reach. It skins quickly, cures to a flexible, durable seal in 1–7 days, and shares the adhesive strength and elastomeric characteristics of the broader Sudbury marine sealant line. Paintable and wet-sandable after cure, with mineral spirits cleanup.
Key Features
- Low viscosity — flows into narrow seams and fine joints
- Fast skinning — skins in minutes
- Full cure: 1–7 days
- Flexible, elastomeric seal after cure
- Paintable and wet-sandable when fully cured
- Adheres to fibreglass, wood, metal, glass, and most plastics
- Clean up with mineral spirits
Compatible Applications
- Windshield and porthole sealing
- Fine deck and cabin seams
- Hatches and vents
- Deck hardware bedding on narrow or tight-fitting joints
- Any seam or joint too narrow for a standard cartridge sealant
Parts Desk Insights
The 350 is the right choice when the joint is too fine or tight for a standard cartridge sealant to fill properly — windshield frames, porthole surrounds, and fine cabin seams are the most common use cases. The low viscosity lets it wick into the joint rather than sitting on top. For larger sealing jobs or areas where a full cartridge is practical, the Sudbury 300 (White, 10 oz.), Sudbury 302 (Black, 10 oz.), and Sudbury 301 (Clear, 10 oz.) are the cartridge-format siblings. For tube-format jobs, see the Sudbury 320 (White, 3 oz.), Sudbury 322 (Black, 3 oz.), and Sudbury 321X (Clear, 3 oz.).
Related Products
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.