What is the difference between polyurethane and spar urethane

When considering the longevity of a product, it is also meaningful to include its desirability. By this, we are referring to the point at which the finish begins to hurt your eyes, and you want a change. The primary reason why you may want to change the undamaged wood finish is ambering. Oil-based finishes have an amber hue, which gets noticeably darker over time. While this might not be a problem on dark woods, it can be displeasing on lighter woods or light paint colors.

But then, even with darker woods, you may not complain for the first few years, but it may eventually get on your nerves. Therefore, it would be safe to say that ambering should also be considered a part of durability. In this argument, oil-based Polyurethane has no leg to stand on. It is undeniably yellow and gets more so as it ages. The same is true for oil-based spar urethane. Where we have a distinction is with the water-based options. Water-based poly is crystal clear and remains that way until the end of time.

Sadly, the same cannot be said for water-based spar urethane. While it is also technically a crystal clear coat, it ambers on light stains and woods. To be fair, some water-based polyurethanes yellow when in contact with white paint, and some poor products will yellow, but they tend to behave well on light wood and stains. Now, this is spar urethanes strong suit and probably a slightly unfair comparison. As mentioned earlier, spar urethane was originally made for boats, so it can weather the weather like no other.

Spar urethane can handle UV rays without the woodturning gray, and it can also take a lot of abuse from water.

However, as this is a slightly softer finish than Polyurethane, spar urethane can look milky when exposed to a lot of moisture. This might make you think the finish is no longer working, but it becomes clear once more when it dries. Polyurethane does not have that problem, but it definitely cannot handle as much moisture or sunlight.

Only exterior Polyurethane normally comes with UV blockers. Polyurethane is a wonderful product for many reasons, one of which is its versatility. As it is a very resistant product, it can be used on any wooden surface. Unfortunately, that is not the same with spar urethane. The significant difference between how to use both products is floors.

While you can apply Polyurethane to wood floors , you cannot do the same with spar urethane. Since spar urethane is a tad soft, it will quickly wear off in high-traffic areas. Being constantly pounded by feet, furniture, shoes, golf clubs, falling chairs, and everything else will damage it. On the other hand, Polyurethane dries hard and remains hard enough to handle any form of abuse for years without weakening. Besides floors, you may not want to use spar urethane on any surface you want to be rock hard.

This could be tabletops, kitchen countertops, or coffee tables — if, like me, you tend to rest your feet on them. As great as spar urethane is, not being able to use it on some of the surfaces that need it most is a bit of an issue. No, you should not put Polyurethane over spar urethane. This is because oil-based Polyurethane or interior varnish have a lower oil ratio than spar urethane.

This will give you a good finish without requiring any extra work. Spar urethanes are a little trickier to use but can be very forgiving and adhere well to multiple types of paint. We recommend you test the adhesion on a small inconspicuous area first before going all out on your project. Spar urethane is a great topcoat for interior and exterior wood surfaces.

Oil-based spar urethane will turn yellow , while water-based spar urethane will not yellow. However, some brands of water-based spar urethane turn yellow when applied to light woods and light stains. Before applying on any light-colored surface, test the spar urethane on a small portion to see if it yellows. Thus, it prevents the original color and grain from fading and the wood retains its original appearance for a longer time. As Urethane is known to prolong the life of the varnish base it is mixed with, the wood surface has a longer protection time before new varnish needs to be re-applied.

Ultra Violet light is known to be damaging to wood if exposed for long periods but correct application of Spar Urethane will help protect the wood. One of its advantages is that it will also not crack when the wood expands and contracts naturally. Spar urethane can be applied to wood in a similar way as standard painting by using either a brush or a roller. However, when bought off the shelf, some types of Spar Urethane are a viscous liquid and if applied directly it can feel almost like painting maple syrup onto the wood surface.

Undiluted Spar Urethane can harden quickly especially if applied in sunny conditions. This tends to make the product that is not diluted far more likely to leave undesired brush stroke marks. Therefore, in most cases, some sort of thinning product is added prior to application.

A spray gun may also be used for application. Thinning will also make it easier to brush. However, with a diluted product, extra coats may be needed to attain the desired level of protection of the wood. Prior to application, the wood must be cleaned and smoothed free of any old flakes of varnish. Spar Urethane is a versatile synthetic varnish and designed so it may be applied over old varnish or paint.

Apart from brushing or spraying, there is a third application method that is quick and leaves no air bubbles or brush stroke marks that are so often encountered when applying varnish. This method is the Wiping Method source. Then, use an old rag, dip it into the diluted varnish and wipe the rag across the wooden surface that needs to be covered. A small rag about the size of your hand should be about the most efficient size for this. Check current prices on Amazon.

Polyurethane coatings are synthetic polymers, or types of plastic made from long chains of repeating molecules. The coatings are designed to be strong but flexible so the material it is applied to can flex and move naturally but without the Polyurethane coating cracking or flaking off. The oil-based type is thicker but requires fewer coats than the water-based type.

If you are looking for an easy-to-apply product that takes less time to dry, an oil-based Polyurethane is probably your best choice however it requires more care to apply and there is a greater chance of leaving brush strokes than the water-based product. It is made by mixing many different chemicals, many of which are unfriendly to the environment due to the emissions they create.

These chemicals will darken over time so the color of the wood finish will alter slightly. Water-based or acrylic polyurethane tends to dry faster and is less smelly which makes it a preferred choice for indoor uses.

Read our article on oil- vs water-based polyurethane where we have covered the differences in detail. Prior to use, Polyurethane should be stirred well to mix the chemicals together that may have separated over time. The product should never be shaken as this will introduce air bubbles that will be visible in the final finished work. The woodwork should first be prepared by rubbing down with sandpaper or wire wool and all debris must be removed with either a blower or vacuum cleaner before applying the Polyurethane.

If the product is applied before the surface has been cleaned, debris will be visible in the end finish , spoiling the job. The application is similar to Spar Urethane except Polyurethane takes longer to dry note that the drying time differs significantly between water-based and oil-based poly, find the details here. For interior surfaces, polyurethane is generally better.

Although be mindful that it does create toxic fumes. You will need to apply the substance in a well-ventilated area while wearing the appropriate protection, particularly a mask that covers the nose and mouth. However, if you cannot apply polyurethane to a surface while being in a well-ventilated area, an example would be a room or basement with poor ventilation, then you should consider spar urethane as a good substitute.

You will still need to wear a mask, but it does dry faster and creates fewer fumes compared to polyurethane. Keep in mind that spars come with a higher oil ratio than oil-based polyurethane or and interior varnish. Always sand the old finish and put the same as what you already have. This will deliver the best finish without extra efforts.

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You may read more about him here or get in touch with him here. Just in case you want to hire pro painters in your local area, you can click here. We can instantly send you free quotes from trusted painters based on your specific requirement. Polyurethane This is one of the most common substances used in the world. Although not used as a finish or coating for every product, it is certainly the most popular.

Spar Urethane vs Polyurethane: Differences It should be noted that both products contain many similar elements. Both are generally lightweight, flexible, and strong when it comes to finishes.