Guide to the Best Marine Spar Varnish

Guide to the Best Marine Spar Varnish

Spar varnish was developed centuries ago to cushion the ship’s wooden spar and other parts on the ship against the harsh weather conditions at sea, like the salty water, rain, and UV degradation.

With all these threats, the wood did not last very long. Yet, ships were mainly made of wood then. Covering wood with varnish helped deal with the problem, but this too posed a challenge. Wood expands and contracts with changing weather, and if the varnish had no room, it would tear up and peel right off.

At the time, without the modern chemistry advancement we enjoy, especially in the field of polymers, they just added oil. We have come a long way since, and although spar varnish is still used on wooden marine vessels, it has been generalized to be used on outdoor wooden items that need protection from harsh weather conditions.

In this article, I will be telling you of the six best marine spar varnishes on the market and everything you need to look for in varnish to get the best.

Here is a list of the best spar varnishes. Let’s go through the list and see how they compare against each other.

1. Rust-Oleum 207008 Marine Spar Varnish

If you are looking for a varnish that enhances wood’s natural beauty and keeps your wood project looking great for a long time, this is the spar varnish to get.

This spar varnish is best used on exterior wooden surfaces above the waterline. With the oil-based formula used in making this varnish, the varnish contracts alongside the wood with the changing weather. This keeps it from cracking and peeling off the wood.

You don’t have to wait for so long for the varnish to dry as it dried in just over two hours.

It’s very durable, and your wooden surfaces will be protected for years against the sun’s UV rays, mildew as well as salt.

It’s a crystal clear varnish, which gives your wooden surfaces beautiful glossy finish while protecting them from the harsh weather conditions.

It’s ideal for railings and trims above water as well as furniture.


  • Very durable
  • Dries to the touch in just over 2 hours
  • Beautiful glossy finish
  • Protects against UV rays, mildew, and salt
  • Perfect for above water wooden surfaces and furniture
  • Affordable


  • You might need more coats to get a good finishing

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2. OLD MASTERS 92304 Spar Varnish, Satin

If you are looking for a nice finish to your woodwork, but you don’t want the extra shine you get with a gloss finish, then you can go with a milder shine that comes with a satin finish. If you choose this direction, then this varnish from Old Masters is some of the best to get on the market.

It helps accentuate your wooden surfaces’ beauty while giving them extra protection against weather elements and UV rays.

It’s very durable, and you will get years out of it before you need to reapply it. They use advanced technology for this paint, and this allows it to contract and expand with the wood when the weather changes without cracking and peeling.

The varnish reapplies very well, and you will net need much sanding between coats like it is with other varnishes. However, you will need to be a lot more patient as it takes longer than other varnishes to dry up.

It’s most suitable on the interior wooden surface like windowsills.


  • Affordable
  • Durable
  • Provides extra UV protection to your wooden surfaces
  • Requires minimal sanding between reapplication


  • Takes longer to dry

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3. OLD MASTERS 92501 Spar Marine Varnish

This is another awesome product from the Old Masters. It’s suitable for both interior wooden surfaces like windowsills as well as exterior woodwork projects.

The varnish penetrates deep into the wood grain to give it superior wood protection to keep it looking great for a long time.

It is an oil-based clear varnish which gives your wood an earthy natural look. It is very durable too, and you will go for years without needing to redo it.


  • Durable
  • Oil-based
  • Gives your wooden surfaces an earthy natural look
  • Suitable for both interior and exterior surfaces


  • You need multiple coats to get a good outcome.

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4. System Three 1855S16 Marine Spar Urethane Varnish

If you have been doing woodwork for a while, you might have realized not all varnishes labeled marine function like marine spar varnish is supposed to. Some will let the water get to the wood beneath, which in turn rots slowly over time.

With this varnish, you will you can relax knowing that your wood is properly protected. It has UV absorbers to protect your wood against sun rays and you also protect the wood from harsh weather elements like rain and salt.

This makes this varnish the ultimate finishing to your outdoors and marine woodwork projects like picnic tables, decks, and boats. It is available in both the shiny, sleek gloss finish and the more subtle and natural satin finish.

When you are applying, you don’t need sanding between coats. It’s very durable, and you will get years of protection before you need to redo it.

The varnish is VOC approved too.


  • Extra protection against harsh weather elements
  • UV absorbers to protect against UV rays
  • VOC approved
  • Does not need sanding between reapplications
  • Suitable for marine and outdoor woodwork


  • None I could find

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5. TotalBoat Lust Marine Varnish

Enhance the natural beauty of your wood using this quality marine varnish. It has superior UV protection to protect your woodwork from the violent UV rays from the sun. It’s also water-resistant which, makes it ideal for boats and external woodwork for outdoor projects.

While you might need days to finish a project because it takes so long for a varnish coat to dry, that is not a problem you will encounter with this varnish as it dries very fast, and therefore, you don’t need to sand the project in between coats.

It’s an oil-based varnish that will not crack and peel off the wood as it expands and contracts with the changing weather. This makes it durable, which means it will be years before you have to apply again.

You can either use the high gloss option if you want some outstanding shine on your wood project or use the matte option that looks a lot more natural and earthy.

It’s available in different sizes, and you can also get a TotalBoat brushing thinner if you want, which works perfectly with the varnish.


  • Very durable
  • Available in matte and gloss options
  • Dries quickly
  • Protects against UV rays and water
  • Does not need sanding in between coats


  • Pay attention to the size you are ordering

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6. OLD MASTERS 92504 Spar Marine Varnish

From the trusted varnish Old masters, this is another spar marine varnish that enhances your wooden projects while giving them the much needed extra protection.

It’s suitable for use on interior surfaces like windowsills, giving them extra UV protection against the sun’s UV rays.

It is quite durable, which means it will be a while before you have to reapply. When you apply, you don’t need to sand the project in between coats.

The varnish is not for use on wooden decks as it’s resistant to harsh weather conditions.


  • UV protection
  • Relatively durable


  • Not very resilient against harsh weather elements

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Considerations for the Best Marine Spar Varnish

The wood varnish is always a good finishing to a nicely done piece of woodwork. Rather than hide the wood in opaque covering like it is when you paint a project, varnish helps accentuate natural wood’s beauty while protecting it from rotting and harsh weather elements.

This is only if you get the right kind of varnish. If you are shopping for marine spar varnish for the first time, here are things to consider.

Mechanical Flexing

If you are looking for marine varnish for an outdoor woodwork project, you should prioritize this one as the most important consideration.

Mechanical flexing is the marine spar varnish’s special ability to expand and contract with the wood with changing weather conditions.

If this is lacking, the varnish will crack when the wood expands and contracts, and within no time, it will be pealing of the woodwork project, leaving it exposed to the weather elements and the damage starts.

Type of Finishing

When it comes to marine spar varnish, you generally get three finishing options to choose from. You can go with matte, gloss or satin.

Most brands will have varnishes for each of these finishes, and you can buy the one you need, so then, what’s the difference? The difference is in the shine level of the finishes.

Gloss is the shiniest varnish. Most people don’t like the gloss finish because it makes the wood look artificial. Matte is the dullest and gives the wood the most natural earthy look. Satin is a shine level between matte and gloss.


While you will have to keep replacing varnish on your woodwork projects once in a while, you want to buy a varnish that gives you the most service. The best kind of varnish will give you at least two years of service before you need to redo it.

Resilience Against Weather Elements

You want to buy varnish that protects your wood from harsh weather elements like the sun’s UV light, water, salt, and heat. This is especially important if you are looking for a varnish to use on outdoor woodwork projects exposed to these elements like say a boat, a deck, or a picnic table.

Suited for the Environment You Need

Some varnishes are only meant for indoor use, while others are meant for outdoor uses only. If you are looking for a varnish to use on an outdoor project, make sure you get a varnish suited for the purpose.

The same thing goes for interior projects as well. Some varnishes are okay to use on both interior and exterior projects too. Just make sure you get the most suitable for your intended use.

Frequently Asked Questions on Marine Spar Varnish?

What is Marine Spar Varnish?

Marine spar varnish is some type of finishing originally designed to protect a ship’s spar and other wooden parts of a ship from the damage caused by weather elements like water, salt, and UV degradation.

Although these varnishes are still used on marine vessels like yachts and boats, it’s been generalized to cater for any other woodwork project that needs protection, especially outdoor ones.

What is the Difference Between Marine Spar Varnish and Polyurethane?

Polyurethane is a kind of varnish made of synthetic resin, which usually lasts longer than marine spar varnish. On the other hand, it is generally made of short oil and is not as durable. However, the marine varnish is better suited for use on outdoor projects as it allows room for the wood to expand and contract.

This ensures that the varnish does not peel off the woodwork, unlike the polyurethane varnish.

In Conclusion

Marine spar varnish is one of the best ways to shield your woodwork pieces from damage that is caused by weather elements, especially if they are outdoors.

While there are many varnish brands labeled marine spar, not all of them will provide your woodwork pieces with the necessary protection needed against weather elements. To get the best, you need to know what to look for in advance. I hope this article helped lead you in the right direction.

While all these varnishes are great, check out the System Three 1855s16 marine spar urethane varnish. It’s great for marine projects, has UV absorbers, is water-resistant, and there is sanding necessary between coats.