Marine Sealant vs Silicone: Solutions for for Superior Sealing

Marine Sealant vs Silicone: Choose marine sealant for heavy-duty, long-lasting performance in the harsh marine environment, and consider silicone for less demanding situations or where cost is a major factor

Marine Sealant:

• Designed specifically for marine environments: Can withstand harsh conditions like saltwater, UV rays, extreme temperatures, and fuel spills.
• Superior flexibility and adhesion: Maintains elasticity to move with boat movement and adheres well to various boat materials like fiberglass, wood, and metal.
• Fungus and mildew resistant: Prevents these common marine problems that can degrade surfaces and compromise the seal.
• Higher initial cost: Compared to regular silicone, marine sealant tends to be pricier.
• Variety of types: Different formulas are available for specific applications like bedding deck hardware, sealing hatches, or filling in cracks.

Silicone:

• More affordable: Generally cheaper than marine sealant.
• Wide range of uses: Can be used for various household and construction applications, not just marine.
• Easier to find: Available at most hardware stores, whereas marine sealant might require specialized locations.
• Less resistant to harsh conditions: May degrade faster in saltwater, UV exposure, and extreme temperatures.
• Lower adhesion: Might not adhere as well to certain boat materials as marine sealant.
• Not as flexible: May crack or tear with boat movement, compromising the seal.
• Less fungus and mildew resistance: More susceptible to growth in marine environments.

Marine-specific bonds are more durable than their non-marine counterparts and adhere to surfaces better, but they also come with a much heftier price tag. Silicones offer a more affordable alternative, but they’re not as tough as marine sealants. 

When to choose Marine Sealant:

• Any exposed sealing on your boat: Hatches, deck hardware, windows, etc.
• Areas subject to constant movement: To maintain a watertight seal despite boat rocking.
• Applications requiring specific properties: Like high heat resistance for engine areas or fuel resistance for fuel lines.

When to choose Silicone:

• Non-critical applications above the waterline: Sealing small gaps or leaks where harsh conditions are less severe.
• Temporary repairs: Until a proper marine sealant solution can be applied.
• Budget-conscious projects: When cost is a primary concern and the application doesn’t demand heavy-duty performance.

Important note:

• Not all “marine silicone” is created equal. Some are simply regular silicone with a marketing label, so check the specifications and ensure it’s formulated for marine use.
• Never use regular silicone on underwater applications. It can degrade quickly and compromise the seal, potentially leading to serious problems.

Here is the difference between sealant vs silicon – 

What Can I Use For Marine Sealant?

Marine sealant is a chemical compound and liquid applied in high concentrations to the surface of a surface, such as timber or metal. It creates an impermeable barrier to slow or prevent water infiltration.

Marine sealant is used in the marine industry to seal ports, hatches, and other openings. It is also used as a rubberized coating to protect boat hulls, frames, and hardware. Marine sealant beads water on contact so it does not allow water to penetrate the wood or metal surfaces to it is applied.

It can be painted or overlaid with polyurethanes or varnish for added protection against weathering and moisture.

3M Marine Adhesive Sealant 5200

Marine sealant, also known as a marine adhesive sealant, is a material used to improve the strength of screws and bolts. Generally, this type of sealant includes an acrylic polymer base that is mixed with various additives and other materials. 

The mixture can be sprayed onto the desired surface and then allowed to dry over a period of time. Marine sealants are used primarily in shipbuilding and maritime construction as well as on boats, docks, piers, or any other underwater structures.

Features

• Long-lastingng formula
• Protects against UV damage
• Acrylic polymer base
• Comes in an aerosol spray bottle
• Available in black, white, and brown colors
• Easy to apply
• No mixing or measuring is involved

What Is Marine Silicone Sealant Used For?

Marine silicone sealant is used to seal any joint between two surfaces and provide a waterproof barrier. It is typically used on boats and where there may be water exposure. 

How Strong Is Marine Adhesive?

The marine adhesive is pretty strong (700 pounds_per_square_inch) but not as strong as marine plywood, which boat builders use to join decking. The strength of the marine sealant depends on the amount applied and the surface being adhered to. Getting a professional installer is the best way to ensure a strong bond.

Is There A Sealant That Can Be Applied Underwater?

Marine sealants can be applied underwater to provide a waterproof barrier. However, we do not recommend using it underwater. It is a silicone-based product, which will break down and lose its strength.

Since the marine adhesive is applied outdoors, the best way to use it is to allow it to dry overnight before submerging the boat. This will ensure the sealant’s strength and durability.

How Long Does It Take For Marine Silicone To Dry?

Expect at least 45 min to dry completely. You can tell when it has fully cured by touching it. As a rule, the less exposure to air, the quicker the sealant will dry (i.e., on a well-ventilated deck, in direct sunlight).

Also, if you apply marine silicone sealant in direct sunlight or hot temperatures, it may take longer for your product to dry and cure. In either case, do not apply too much at once and allow time to heal before continuing the application process.

Marine Sealant Below The Waterline

3M Marine Sealant is a newer product that has been on the market only since 2012. It’s based on a silicone sealant formulation, but it contains an additional ingredient to make it hold up better in marine environments. 

It’s meant to be used below the waterline, where it resists degradation from UV radiation. It cures quickly and has a working time of 30 minutes in temperatures up to 90º F (32º C). It’s not appropriate for use on above-waterline applications.

Can Silicone Be Used Below The Waterline?

No, silicone cannot be used below the waterline. Silicone is not watertight and will deteriorate, especially if exposed to sunlight.

What Sealant Will Cure Underwater?

AquaFlex Underwater Sealant is a single-component, quick-setting silicone sealant that will cure underwater. AquaFlex is a grey, one-component sealant. Silicone comes in a wide variety of colors and two different components (a base & catalyst). AquaFlex & silicone are flexible, UV resistant, waterproof, and airtight when cured. 

Can 3M 4200 Be Used Below The Waterline?

Yes, 3M 4200 can be used below the waterline. 3M 4200 is a grey, two-component silicone sealant that will cure underwater. 3M 4200 comes in a caulking tube and is a squishy material when first applied, but after curing, it becomes rigid, glass-like, and waterproof. 

Can Loctite PL Marine Be Applied Underwater?

No, Loctite PL Marine is a two-component, epoxy-based sealant. When cured (underwater), it turns into a hard, glass-like, and waterproof material.

Marine Sealant For Wood 

They are available in various types, including polyurethane, epoxy, varnish, or acrylic sealant. Silicone for wood is a liquid or paste applied with a brush or roller to the surface and then hardened.

It is primarily used for protective purposes and for decorating furniture or craft projects but can also be used as waterproofing seals on boats.

When you search for sealant for wood, you need to ensure that it is used in marine environments. This is because the original sealant for wooden boats was made from tar, although the tar sealants have been replaced with silicone-type sealants.

Silicone is more robust than tar and is more resistant to moisture and heat – this makes it a better choice for use on a boat or in any marine environment.

What Is The Best Waterproof Sealer For Wood?

Seal-Once is a waterproof sealant that is designed for marine and outdoor use. The key ingredient for a good sealant is a silicone-based acrylic copolymer. This ingredient has two main benefits that sealants without it lack: water repellency and durability.

Silicone-based acrylic copolymers are absorbent, so they give your surface the ability to repel water droplets. This will help prevent the buildup of mold and mildew on the surface of your boards, which typically happens with unsealed wood over time.

Read More About: Why Does Sealant Foam Rot

Seal-Once Marine Premium Wood Sealer

Seal-Once Marine Premium Wood Sealer is a product designed for use on cedar, redwood, and oak. It is a one-component wood sealer specifically designed to nourish and protect the wood to reduce the need for future repair work. It will also heal cracks and reduce the effects of splinters.

Features

• It comes in a spray bottle that can be reused by simply washing it out.
• Waterproof
• It is non-toxic
• It works in all weather conditions
• Users have stated that it does not inhibit the wood’s natural color
• It will not stain or rot the wood
• Users claim to be able to see results after about ten days
• The wood will appear to shine and can be polished with a cloth or polishing brush, meaning

How Do Marines Seal The Wood?

Marines seal the wood with a marine sealant because this type of sealant is designed to protect boats from roving salt water. The correct color for Marine’s silicone is black. Marine Silicone does not come in a variety of colors. It is also oilier than silicone used for bathtub caulking.

Is There A Permanent Wood Sealer?

SealMaxx wood sealant is a water-based wood sealer that dries clear, and will not yellow or crack over time. It is great for water tables and other decorative wood surfaces that you want to protect from moisture. Outdoor furniture can be given extra protection from moisture and insects by coating it with SealMaxx wood sealer.

Silicone Sealant 

This is a type of sealant that is used to stop water and air leaks in buildings, especially in walls and windows. Silicon products are created by mixing sand with silicone. 

There are many types of silicone sealants on the market today, and each one has different features. Some are adhesive, some stretchable, and some have fluid encapsulation agents for long-term protection from moisture fogging damage.

Read More About: Can Sealant Foam Be Used On Rotten Wood

What Type Of Silicone Can Be Used Underwater? 

3m marine grade silicone sealant can be used. Both 3m Marine grade silicone sealant and silicone are waterproof, but there are a few distinctions between them. Silicone is easier to apply and comes in more colors, making it a popular choice for DIY enthusiasts; however, the downside is that oil can contaminate silicone. 

This doesn’t affect marine-grade silicone sealant, which is why it’s better for fishing or if you’re going to be boating on the water.

3M Marine Grade Silicone Sealant

3M Marine Grade Silicone Sealant is a rubberized paste sealant for external use. It is designed to provide an excellent waterproof barrier for seams, joints, and openings in the hull, deck, and superstructure of boats in marine applications.

The sealant has a very high degree of resistance to weathering, ozone, and other atmospheric agents that cause the degradation of caulking compounds.

Features

• High quality
• Good gap filling
• Good UV resistance
• Excellent adhesion to most building materials
• Waterproof, flexible, and tear-resistant
• Highly resilient in a wide range of climates and temperatures.
• Professional uses: Marine
• Outdoor Uses: Above waterline applications in marine environments.

FAQs

Does Silicone Caulk Work Underwater?

There is a vast array of silicone caulk that can be used underwater. Silicone caulk is primarily applied in silicone caulking, string silicone sealant, or tape sealant. It’s used for sealing and adhering objects such as bathtubs, sinks, tiles, showers, and guttering. It’s resistant to moisture and helps slightly repel water.

Can Silicone Caulk Be Used Underwater?

Yes, silicone caulk is water resistant even though you can apply it underwater. If you’re wondering if silicone caulk can be used underwater, it’s also worth mentioning that it will dry up very quickly and is entirely watertight.

Is There A Sealant That Can Be Applied Underwater?

Yes, a sealant called String Silicone Sealant can be used underwater. String Silicone Sealant is made of polyurethane and will adhere to any smooth surface underwater. The sealant is a very flexible rubberized string that won’t get stuck in cracks.

Will Silicone Continue To Cure Underwater?

Once silicone sealant is applied, it will dry out and remain completely watertight. If you plan on caulking your bathroom, use waterproof adhesive tape as a more durable solution. Silicone caulk can be applied underwater if careful not to get water into the joints.

Is Rtv Silicone Marine Grade?

No, RTV silicone sealant is not marine grade. RTV silicone sealant is a non-permanent sealant that dries out after 24 hours. It’s commonly used in car and plumbing repairs where the application should be temporary.

The Great Adhesive and Sealant Strength Test

Final Word

This is all about Marine Sealant vs Silicone Sealant. This blog is meant to help you to decide on the best sealant for your needs. Your goal should be to find a product that is compatible with your project, offers longevity and value over the long term, and meets your needs at a reasonable price point.