New DIY push: Sika’s Sikaflex-291 LOT boosts all-weather marine repairs

Sika is extending its reach into the US marine DIY market with Sikaflex-291 LOT, a low-odor, one-component polyurethane sealant and adhesive designed for flexible, all-weather repairs on boats and other marine craft.

Edited by ad hoc news New Releases & Launches Desk. Reviewed before publication on 06/15/2026 at 9:47 PM ET. Details in the imprint.

Sika is sharpening its US marine portfolio with Sikaflex-291 LOT, a one-component polyurethane sealant and adhesive positioned for do-it-yourself repairs and professional refits in demanding marine environments. The product is marketed as a low-odor, non-sag formulation that can be applied in a wide range of temperatures while maintaining flexible, durable bonds above and below deck on fiberglass, wood, metal and other common boatbuilding substrates.

What Sikaflex-291 LOT is designed to do

According to Sika’s marine documentation, Sikaflex-291 LOT is a moisture-curing, elastic polyurethane sealant that combines sealing and bonding functions in a single product aimed at general marine construction and repair tasks such as deck hardware bedding, interior joint sealing and minor structural bonding on leisure and commercial vessels. The official product page describes it as suitable for a broad range of substrates including fiberglass-reinforced plastic (FRP), wood, metal and coated surfaces in above-waterline applications. The “LOT” suffix stands for long open time, signaling that users have more working time to position parts or tool joints before the sealant skins over.

From a technical perspective, the sealant is formulated to remain permanently elastic after curing, allowing it to accommodate differential movement between substrates caused by vibration, hull flexing and temperature swings that are typical in marine environments. Independent marine distributors highlight that Sikaflex-291 LOT is non-corrosive and isocyanate-based, resisting saltwater exposure and weathering while maintaining adhesion when properly applied over clean, dry surfaces and, where necessary, compatible Sika primers specified in the company’s marine bonding guides. This positions the product as a versatile option for tasks ranging from sealing deck joints to bonding small fittings on sailboats, fishing boats and smaller commercial craft.

The low-odor aspect is emphasized in US marketing materials because many marine repairs occur in confined spaces such as cabins, engine compartments and lazarettes, where traditional high-solvent sealants can be uncomfortable to use. Retail listings point out that Sikaflex-291 LOT is paintable and sandable after full cure, which is attractive for visible areas on deck or in the cabin where cosmetic finish matters as much as water tightness. For DIY boat owners, this combination of flexibility, paintability and tolerance of marine conditions is intended to reduce the need to stock multiple separate sealants for common maintenance tasks.

In the US market, Sikaflex-291 LOT is typically available in 10.3 fl oz cartridges in common marine colors such as white and black, aimed at both retail shelves in marine supply chains and professional yards sourcing through distribution. Sika’s North American marine documentation notes recommended application temperature ranges roughly aligned with typical boatyard conditions, and the long open time characteristic means the sealant is less sensitive to hurried application in warm climates than fast-skinning variants that can become difficult to tool. As with most polyurethane marine sealants, cure time depends on temperature and humidity, with full mechanical properties developing over several days.

European marine outlets categorize Sikaflex-291 LOT alongside Sika’s wider Sikaflex marine range, which includes more specialized products for high-strength structural bonding and direct glazing. Sika’s global marine portfolio presentation describes the 291 family as the general-purpose workhorse for sealing and bonding above the waterline, giving it a central role in the brand’s offering to both original equipment manufacturers and refit yards. For US retail investors and consumers this underlines that Sikaflex-291 LOT is not an experimental niche product but part of a core, widely used technology platform.

Strategically, Sikaflex-291 LOT fits with Sika’s broader push into value-added systems for the construction and transportation sectors, where the company reports annual sales in the low double-digit billion Swiss franc range and emphasizes marine as a specialized but important segment of its adhesives and sealants business. Sika is headquartered in Baar, Switzerland and its shares (ISIN CH0418792922) trade on the SIX Swiss Exchange; according to recent market data, the stock closed in Zurich in the triple-digit Swiss franc range in mid-June 2026, reflecting the scale of its global specialty chemicals footprint. The company’s investor relations materials highlight structural growth drivers in construction chemicals and transportation, with marine sealing and bonding forming one of several application-focused verticals.

Sikaflex-291 LOT marine sealant at a glance

• Product: Sikaflex-291 LOT
• Manufacturer: Sika AG
• Category: New Release / Marine sealant and adhesive
• Launch date: Ongoing availability; marketed in the US as part of Sika’s marine Sikaflex range in recent years
• MSRP / Price: Typically in the mid-teens USD per 10.3 fl oz cartridge at US marine retailers (varies by seller and color)
• Availability: US marine supply chains, online marine retailers and regional distributors
• Target audience: DIY boat owners, professional refit yards and marine OEMs needing flexible above-waterline sealing and light bonding
• Key differentiator / USP: Low-odor, long open time polyurethane formula designed for elastic, paintable marine sealing and bonding on multiple substrates

This article was a.i.-assisted and editorially reviewed. Product information without warranty; prices and availability may change at short notice. Not investment advice and not a buy or sell recommendation. Trading involves risk up to and including the total loss of invested capital.