We all know that furniture has to be protected especially wooden ones and if you leave it outdoors to stay all the time. Since wood is a living being it is prone to gain issues due to weather changes, so we can say that it is mandatory to protect it completely.
The question is which protection you should choose. The most popular ones are polyurethane and spar urethane, but it is essential to understand the difference and advantages/disadvantages of both of them before you make up your mind.
We are here to present you ways to differentiate these two wood protection products:
What’s the Difference Between Spar Urethane and Polyurethane?
Polyurethane coatings became popular in the middle of the 20th century. They come in liquid form, and the main idea and reason for their applying are to protect the wooden surface.
Have in mind that main ingredients that it features are nitrogen-based chemical amalgams, vegetable oil, mineral spirits, and isocyanates.
Nitrogen is vital because it will help you protect the finish from chipping, while isocyanates will create additional thickness.
Polyurethane coating features a wide array of chemicals that are affecting the environment due to emissions. Of course, it will protect your furniture so that it can resist the damage especially when it comes to outdoor weather conditions.
But it will create discoloration, which means that wood will become darker as time goes by.
On the other hand spar urethane is different than polyurethane, and even though it features several compounds, there are more differences than similarities — for instance, polyurethane stains and chips with less effective when compared with spar alternative.
It is also a better choice that will stand up with substances such as alcohol. On the other hand, spar urethane is stronger of the two, and it will coat square feet per gallon, while polyurethane will stick with more problem on the surfaces.
Polyurethane finish features a few downsides because it cures, sets and rises more slowly than spar urethane that could dry in a matter of minutes.
Both finish types come with a spray application. However, brushing spar urethane is a hardworking job because it tends to harden faster, and will produce as result visible brush lines
Therefore, the surface or wall has to be completely even if you want to add spar urethane. On the other hand, polyurethane should be sprayed after you finish the surface.
It will produce more significant shine which is the main reason for its popularity.
Which Urethane Is Better To Use?
We cannot say which one is better for your specific needs and requirements because it depends on various factors. The type and nature of your project will dictate which is the best choice for you.
Have in mind that spar urethane tends to be more expensive than polyurethane and its quality is less consistent depending on the brand, of course.
Polyurethane, on the other hand, has a greater tendency to promote ultraviolet light so it will discolor your furniture.
Pros And Cons Of Using Spar Urethane
The first thing that you should know about spar urethane is that it features low levels of odor and toxicity. Therefore, it is the best choice for your requirements in case that you have allergy issues or if you want to protect the environment altogether.
At the same time choosing this particular type of wood finish, is great because you will gain a long lasting solution but you have to maintain the furniture properly to get all these capabilities.
You will be able to use it both inside and outside, which is another reason for its popularity because it can withstand any weather conditions.
The main disadvantage of this particular type of coating is that paint won’t be as durable as oil-based polyurethane. At the same time, colors won’t match with the wood in all times.
Have in mind that when it comes to extreme heat conditions, water-based urethane is not that efficient.
Pros And Cons Of Using Polyurethane
The advantages of using polyurethane are also essential to consider especially if you want to determine which type is the best for your specific needs. It is better when it comes to durability, high-quality finishes, and longevity.
It can withstand harsh conditions such as immersive heat or cold, and due to its waterproof features, you will be able to protect your furniture against weather damage.
The disadvantages of using oil-based polyurethane are the high amount of toxicity that it contains due to harmful chemicals that will require more time to dry than water based.
At the same time, the odor can cause you harm which means that you have to let it dry in a highly ventilated area.
Sometimes it can create air bubbles during the finish, so that could mess up the entire coating since the removing of polyurethane from wood can be time-consuming and tricky.
Conclusion
Even though these two urethanes are similar, both of them feature unique qualities and features that will make them perfect products for your specific needs.
Of course, everything depends on what you want to use and where are you placing the pieces of furniture you wish to protect.
In case that you have pets or children, and lack of area that features excellent ventilation, you should avoid using oil-based coating such as polyurethane and choose instead spar that will provide you less toxicity and odor altogether.
Water-based coatings are a friendlier option for DIY enthusiasts that do not have a well-ventilated workshop where they can leave it to dry.
However, in case that you have a proper workspace, using polyurethane will provide you results with higher quality for less time especially when it comes to the aesthetical perspective of your finish.
But still, you should be extra careful on how many fumes you are breathing and try to take a break between coating, or wear a mask that will reduce the number of fumes that you’re inhaling during the project.
We hope that you understood the difference between these two types of urethanes, and if you have additional questions, you can ask them by leaving a comment in the section below.
Please proofread better before posting. I was so distracted by the poor sentence structure — needing to read and re-read — that it was difficult to focus on the actual content.
E.g.,:
“Have in mind that main ingredients that it features are . . .”
“spar urethane is stronger of the two, and it will coat square feet per gallon, while polyurethane will stick with more problem on the surfaces.”
Pickey ass mf
Ed is right. This is one of the most poorly written “subject matter expert” pieces I’ve ever read. Unfortunately the writer lost credibility by his exceedingly poor writing.
This is perhaps the worst written and most confusing article on wood finishing I have ever seen. Some of the statements seem to contradict others and some of them simply make no sense whatsoever.
This article attempts to compare (oil-based) spar urethane to (oil-based polyurethane). Everything is going ok but then the author randomly mentions water -based finishes. Below are shown just a few of the crazy statements made. I would need to re-read but I think there are one or two more.
“On the other hand spar urethane is different than polyurethane, and even though it features several compounds, there are more differences than similarities — for instance, polyurethane stains and chips with less effective when compared with spar alternative.” (what does this mean?)
“Therefore, the surface or wall has to be completely even if you want to add spar urethane. On the other hand, polyurethane should be sprayed after you finish the surface.” (I thought that the urethane or poly WAS the finish. What does this mean, that I should spray poly on top of spar?)
“The main disadvantage of this particular type of coating is that paint won’t be as durable as oil-based polyurethane. At the same time, colors won’t match with the wood in all times.” (What has paint got to do with anything? We’re not using paint.)
“Have in mind that when it comes to extreme heat conditions, water-based urethane is not that efficient.” (What does that mean?”
Which is best to put on small children furniture or is it to toxic?
Agree with Ed!
I agree.
Any valuable information you may have is lost in the horrendous use of the language.
It sounds like a bad bot translation.
I was concerned that I may have had a small stroke when reading this article. The structure of sentences was below the chart. I was relieved to learn others had the same feeling. I had no choice but to discount all of its information.
“I tell him for job, he ask me no”.
I agree this author definitely needs a proofreader, for both spelling and composition. I found it hard to follow as it jerks around so much and leaves thoughts hanging in midair.
All of that said the article had a lot of good informational nuggets hidden within.
Agree with all above comments, but seems even worse than a bad bot translation.
To me it doesn’t seem the author really understands the materials he attempts to discuss.
I’ll try to lend a little of my experiences with the urethanes…
He never even mentions that Spar Urethane is mainly for outdoor use (UV exposed applications), that it’s softer for better expansion/contraction. As softer it’s typically it’s not used for common hardwood floors (that said, I have used it on an ext door threshold and sailboat cockpit floor successfully).
Re. fumes… Spar Urethane seems to stink as bad when curing as any interior Urethane, as both are solvent based… though this observation isn’t a quantified 🙂
Only water-based urethane has minimal fumes, but haven’t seen it sold (so far) as an exterior Spar type product.
The water-based urethane seems to lay down less than 1/4 thick per coat than the oil based versions.
As to applications, it should be noted that the urethanes are great for splashes, but if exposed to standing water (like near a sink) they get white, gooey and ruined… even the oil-based type. Consider 2-part clear epoxy for those spots as it can be underwater (as on boat hulls). But everything has trade-offs, as epoxy takes heat even less-well than cured urethane… (think hot coffee cup rings into the epoxy)… yup been there.
And should be mentioned every urethane coating used outdoors will fail if exposed to UV… Spar or not, so be prepared for the fun job of stripping and recoating every 2-6 years.
I have had good luck with the water based spar and regular urethane. I use it on furniture projects I make, and with it being water based, I’m not using quarts of paint thinners for clean up. That seems to be better for the environment. Lowes stopped carrying the water based spar, but when they did, I used it. They still have the Polycrylic in the blue can.
Either type of water based polyurethane seems to work well. I have been brushing on a couple coats, then wet sanding lightly, and spraying the final coat or two. A cheap spray gun from the cheap tool sore works great and cleans up easily. When the gun gets too far gone, I buy another $9.00 spray gun. USE A LOT OF VENTILATION IF YOU DO THIS.
I’m a total newbie and I thought that this article was not definitive, as I had hoped. I can not call the author out on the points, but I leave this “clear as mud.”
Guys. Chill please. Highly skilled craftsmen tend not to be English scholars – they spend their efforts mastering their craft.
Original author, thank you for your publication.
This guy is borderline illiterate.
TELL THIS GUY NOT TO BREATHE FUMES BEFORE ATTEMPTING TO WRITE ARTICLE!
A lot of criticism from a bunch of newbies needing to read an article to figure stuff out.
It was confusing I went back and forth to decipher. The comments were cynical but amusing. But he’s right you shouldn’t criticize if you have to read up on it yourself.
I’m pretty sure the author is not a native English speaker. Phrases like “polyurethane stains and chips with less effective when compared with spar alternative” don’t have any meaning in English. There were many similar meaningless phrases, but I’m sure the author was trying to communicate something – he just didn’t have the tools to do it. I’d recommend employing a native English speaker to proof-read your articles in the future. Good try.
If you are not familiar with a subject, reading clear and well written articles by an expert is one of the best ways to learn. This author may be an expert, but it doesn’t come across that way in this article which is very poorly written. He could have asked a friend to proof read it to see if it made sense.