Spar Marine Varnish VS Spar Urethane For Paddles, Canoes And Small boats


That canoe, boat, or paddle is exposed to the elements whenever you are in the great outdoors. You want them to remain in good condition for the next time you plan to embark on your outdoorsy adventures.

One of the ways that you can do this is by applying a coating that protects the wood. This helps to maintain the structural integrity of the canoe, boat, or paddle. Two of the best coatings that you can use are spar varnish vs spar urethane.

But which of the two do you use and when do you use them?

This is the difference between spar varnish vs spar urethane for paddles, canoes, and small boats.

Spar marine varnish

Spar marine varnish is made to provide wooden surfaces with protection from the elements while still allowing the wood to remain flexible. The wood can contract and expand under the temperature as needed.

This is not something that you will worry about if you use aluminum vs fiberglass canoes. That said you may still need to ensure that the paint job is protected.

However, something to keep in mind with your boat or canoe is that spar marine varnish is designed for the parts of the boat that remain above the water. That said it is effective at preventing scratches, providing heat and UV protection as well as preventing chemical and solvent damage.

There are two main types of spar marine varnish—gloss or satin and the one you use will determine the appearance of the surface. Keep in mind that you may need to apply regular coatings as spar marine varnish tends to flake or chip off.

When applying spar marine varnish, you may need to apply more than a single coat. After the first coat, it’s important to give it several hours to dry before you can apply the second coat. If you want to apply the third coat, you can do this as well after allowing the second coat enough time to dry out.

Make sure that the area you choose to apply the varnish is free from dust, direct sunlight, or water as these will affect the outcome of the application.  Also, use natural bristles or a foam brush to provide a clean and smooth result.  If you use a fiberglass canoe, check out the kayak or canoe oil canning guide to learn how to fix the dents.

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Spur urethane

Spar varnish vs spar urethane is similar in that they provide a layer over the wood for protection against the elements.  It also allows the wood to expand, contract, or flex with temperature changes. However, spur urethane takes things a step further as it is designed to be water-resistant.

Another major difference is in its composition. Spur urethane can be oil-based or water-based. It can however still come in hi-gloss, satin as well as semi-gloss.

All varnishes will mainly be composed of three main independents. These include oils, resins, and solvents. Altering the proportion of these three is going to result in different properties and abilities.

The canoe sitting position is important as it prevents you from collapsing and getting water in the hull which could damage it if it stays there long enough and if the canoe is made from wood.

The proportions of oil to resin is particularly important. For example, if you were to add a lot less oil and more oil to the mixture, the result would be a product that is both hard and brittle. This will not work for outdoor applications as the varnish must flex easily.

Instead, the best application should have more oil allowing or more flexibility with temperature changes. This can also be called long-oil varnish as it expands and contracts easily without cracking.

Types of oils used


Linseed oil is the most popular oil used for formulating and making varnish. One of its main benefits is that it is also quite affordable which makes it an ideal choice for both indoor and outdoor use. Tung oil, however, has been shown to perform better. It is of higher quality which also makes it more expensive.

This could explain why the high-quality spar urethane vs spar varnish resins that are made from Tung oil is also costlier.

Types of resins used

Phenolic resins are the best resins for outdoor use but not all spar urethanes are made from this type of resin. There are also better-quality resins that will ultimately result in better quality and more expensive products.

Some of these good resins include alkyd resins.

Other additives

Resins and oils may be the main ingredients but other additives make the products more resistant to the elements. An example is UV blockers that provide extra resistance to UV rays.

Since spar urethane is resistant to UV rays, it is highly effective at preventing the paint on boats and canoes from fading. This is especially so for canoes or boats that spend most of their time outdoors. The other main benefit of UV protection is that the wood can maintain its structural integrity for longer.

The UV radiation is known to cause damage to wood over time and while you may have the option of using epoxy, this does not flex as easily and will crack as the wood expands, contracts, or flexes with the temperature. Remember to always have a life jacket for boating when on the boat.

Spar varnish vs spar urethane, which is better?

Both spar varnish vs spar urethane is effective at protecting wooden surfaces on your canoe, paddle, or boat. Which of the two you choose will come down to how much maintenance you plan on doing as well as your budget.

Spar urethane has a higher level of moisture protection and is, therefore, a great choice for paddles or the underside of boats or canoes. You may also need to do less maintenance as it is more durable and thus needs fewer applications compared to spar varnish. However, keep in mind that between spar urethane vs spar varnish, it is the urethane that is costlier.

The bottom line is to provide enough protection to boats, canoes as well as paddle surfaces. Without such products and regular maintenance, the wooden surfaces could quickly deteriorate from UV radiation and moisture.

A useful tip is to always observe rough water boating tips when you are out at sea.

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For the best protection against harsh weather elements and to ensure that the paddles, boats, and canoes remain in optimal condition for the best performance, you will need to perform regular maintenance. Choosing a good coating between spar urethane vs spar varnish will keep the wood safe from moisture and the effects of the sun thereby improving the durability of the boat, canoe, or paddle.

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