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Does polyurethane get a bad rap?

3K views 35 replies 23 participants last post by  OSU55 
#1 · (Edited by Moderator)
I was reading a comment on another thread this morning, one we've all seen some version of a thousand times, about someone disliking poly because it looks like plastic. It started me thinking about whether this is a fair criticism, or maybe just a bias based on how poly gets used sometimes.

Granted, some folks think every project should be finished with globs of high-gloss poly, and the result is not always pretty. Some projects are just better if you leave the natural texture of the would exposed to the eyes and hands. But if you're going to put some sort of topcoat on a piece, is there really that much aesthetic difference between, say, a glossy lacquer finish and a glossy poly finish?

There are many factors that go into choosing a topcoat: ease of application, durability, water resistance, to name a few. But purely from the standpoint of appearance, is "plastic-looking" a valid criticism of poly, or is it more about how a finish is applied rather than which finish is applied?

I'll go pop some popcorn and wait for the fireworks to start. :)
 
#3 ·
In my opinion, it's all application. I like poly for many reasons (durability being prime), but I do despise the 'plastic' look. When I use poly, I kill the gloss by finishing with 0000 steel wool and a scrub with brown paper. I only use the 'gloss' poly (versus the satin) since the satin has the dulling additive which can eventually obscure the wood.

As to the difference between a glossy poly and lacquer, consider that the lacquer in the end is a single layer of finish if applied properly. Each coat of lacquer 'melts' into the previous coat. Poly doesn't do that. After extensive sanding to get a flawless, flat surface, the poly has the ghost rings present where the strata of each finish layer is visible, the lacquer doesn't.

This is a discussion that could go on forever!
 
#4 ·
I think poly has its place and uses. Durability is a big plus to it. I am a "close to the wood" type guy. I love the oil finishes, specifically Danish oil with Shellac over it. I use poly if I have to have the durability factor. Otherwise I avoid it.
 
#5 ·
I think it all depends what you want the end result to look like. One or two thin application can show the texture. Several application puts the wood "under glass" or plastic if it not gloss. There is a way to do a french polish with poly as well. I put several coats of it on my wood kitchen counter top 24 years or so ago and it is still holding up. Same with my walnut dining room table. It has made it past 3 children being born and raised and at this point it could use a fresh coat.
It all depends what the function of the object to be covered is going to be. I certainly would not have used lacquer
with five females in the house using nail polish and such.
 
#6 · (Edited by Moderator)
Not in my opinion, there is no polyanything in my shop and it deserves every curse word aimed at it. Besides the look, it has problems with adhesion…hence the sanding between coats for tooth. As much as I hate it, there are times when it's the right finish for the job: like floors, where it's abrasion/scratch resistance is worth it's weight in gold. But generally, there are much nicer varnishes to use, the popularity of the resin is due to 2 things (IMHO): Norm's never ending " a coat of POLY", and 2 it's low cost (that's the manufacturer's draw). Just my opinion; but that's what you were asking, right?
 
#9 ·
Just a neat little fact about finishes…

I went on a tour of the Gibson (electric) guitar factory here in Nashville about a year ago and saw some pretty amazing stuff. Our tour guide was the guy in charge of selecting, storing, and maintaining all of the hardwood that was used for making the guitars. He also dealt with grain orientation of glue ups and such. He is very knowledgeable and there's no doubt he knows the physical properties of wood and how it reacts to its change in environment (temp, humidity etc.). He is basically the wood guru there at Gibson. During the tour through the finishing section of the plant, he also went into a lot of detail as to the reason for selecting the type of finish that they use. I asked him if he would mind telling us what they use and he gladly said that it was Sherwin Williams Hi-Bild Lacquer. Just the regular ol' stuff anyone else can buy. He said that they also use a conditioner/sanding sealer which I would assume is the sanding sealer made by Sherwin Williams. They use tinted lacquer to get all of thise wild colors on their guitars, too. While he was so willing to divulge information I asked him what type of glue they use and he said Titebond III. I also asked him about the sandpaper grit progression they use from sanding the bare wood to finishing/buffing the lacquer, but I don't remember the grits. He also mentioned that another advantage to a lacquer finish is that when a customer sends in a guitar to have it refinished, they can easily clean the guitar, prep, and refinish, with the resulting finish just as good as the day it was manufactured.

I say all of this just to point out that Gibson has made hundreds of thousands of guitars, knows how to finish wood, and has experimented with everything out there, and they choose Lacquer.

I've had a lot of experience with Sherwin Williams lacquer since this is what my father has used on all of his cabinets and furniture. I can attest to the quality of finish that can be achieved by using lacquer and its ability to be touched up or completely refinished many years down the road. This is also why I chose to use it recently on a set of dining chairs and table that I built. The tables and chairs have already gotten some scratches but I know that a few years down the road I will be able to throw it all out in the garage, slap on a new finish and not have to worry about peeling or flaking between the original and the new finish.

I have no doubt that poly provides an excellent finish but I would be hesitant to use it on anything that you would like to be easily serviceable for future refinishes.

Disclaimer: I'm, by no mean, a expert on wood finishes nor do I claim to be. I'm just sharing some of my experience.

Regards,

Nathan

Thought I'd share a few of the pictures I took…
Building Gas Ceiling Metal Engineering


Public space Wood Metal Leisure Market


String instrument Musical instrument Guitar String instrument Wood


Building Engineering Machine Factory Metal
 

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#10 ·
I think satin poly and satin lacquer look about the same. I use lacquer because it dries faster. Traditional poly can take 24-48 hours for each coat to dry. That is a lot of time for dust to find its way into the finish.
 
#11 ·
Polyurethane offers excellent protection to a piece that will be high use abuse, it is easy to use as a wipe on product, it's widely available, and it is accessible to any wood worker. If you thin it and build slowly, you can minimize the plastic looking effect. Oil based versus Water Bourne yields different looks, I like WB on light woods only, it makes dark wood look hazy. I'd agree with Fred, it's really best suited for floors and other protection projects.

Oil- I use Osmo on alot of projects, it has the easy of a wipe on poly but leaves a non building rich finish on wood. It's expensive and takes a little longer to dry and finish, but like other oils, it's gorgeous. My recommendation to new finishers is go oil products first, perfect their use, then explore.

Lacquer- my go to for projects that will get more abuse, but it requires spraying to do it right… That makes it hard for the average woodworker, but then again there are rattle cans for small projects.

In the end, to me, a great project is determined by high attention surface preperation. No machine marks, no tearout, entire surfaces evenly sanded with a consistent scratch pattern. The common American will have no idea if you used poly, lacquer, oil, shellac… What they will notice is how the light reflects off you falwlessly sanded surface because that's what matters, how it looks.
 
#12 ·
I love poly… you can get just about any desired look you want with it, it's tough as nails and is basically fool proof. With wipe-on (50/50 mix) poly, it can be dry to the touch in less than 30 minutes (initial coats can dry in as little as a couple of minutes), and you can easily lay down 6-8 or more coats in a day without the need for sanding in between.

Cheers,
Brad
 
#13 ·
I have, for many years, been a poly hate monger based on past experiences. But my wife bought some for something and had a bunch left over so I took it to the shop. To my surprise there is hardly any smell, dries in minutes, and two coats did not appear plastic at all.
 
#14 ·
I've got a kitchen table I did nearly 30 years ago and two boys grown using it and numerous get togethers and its a tank. From a durability standpoint its dang hard to beat. I think it has it places and uses

I think every finish has +'s and -'s and depending on personal tastes and looks. Just like there are diff's between oil base and water base. Wipe on and spray. Not an easy either or?

Personally I do not prefer it, but it's not the anti-Christ of finishes either. Shellac is a great finish, but would not use it where water could be an issue etc.

I like in-the-wood finishes and low gloss but thats just me. Depends on what the client wants, that's the one thats best :)
 
#16 · (Edited by Moderator)
I don't think poly gets a bad rap as much as it gets overused and used incorrectly too often. There are times it is the most appropriate finish, there are other times a different finish would work/look better. Too many coats of poly does give a "plasticy" look, IMHO. However on a tabletop or floor, a little bit plasticy is better than a lot beat up.

Because it's the finish that most people are aware of, it's the one they grab when starting out. Overuse and inexperience is a bad combination, especially with finishing. As someone progresses in their woodworking and really starts to learn about finishes, whole new horizons open up. Plus, they get better at prep and application, which results in a better look, as well.
 
#17 · (Edited by Moderator)
I am not pro or con on any finish as each project needs it's own special treatment!
If that were not the case then why are there so many options for the amateurs and professionals?
There are many variables that determine which finish is best for each project.

The only finish I will never use is stain and poly combinations available!
 
#19 ·
sometimes…the best finish for popcorn is butter, but if you slap on too much it gets a plasticy taste… sometimes simply salt does the job and leaves the natural flavor and texture of the popped corn.

there is a time and place for everything…
 
#20 ·
Great topic Charlie! I use a lot of Spar urethane when I need durability but restrict its use to indoor projects (even though it is marketed as an exterior finish). To me , it has a less plastic look. It contains "long oils" which add some color/warmth to the wood.
 
#21 · (Edited by Moderator)
I think some good points have been made, and no one has even started any name-calling yet. :)

A lot of comments have mentioned considerations like durability, drying time, and such. It's been a good discussion, but I was really just asking about appearance, and whether or not you think it really looks bad,or if that's just a put-down used by people who prefer more traditional finishes.
 
#22 ·
It is a plastic so if you get it thick it's going to look like plastic but it seems like there have been improvements since the stuff I used in the 80's. This year is the first time I've used polyurethane since around 1989 when I refinished a desk for some friends.
 
#23 ·
Just a tweak to the statement about Spar containing "long oils". A long oil varnish simply has more oil in the mixture that's cooked to become varnish. The higher oil content gives the result the more flexible feature.
 
#24 ·
Nathan - you may be aware of the studies done on tonal properties of wood and finishes in stringed instruments. Turns out lacquer is way more tonal than poly, mainly because it dries to a harder finish and seems to be able to generate vibrations better than other finishes. Some woods are also more tonal, like maple and ash, but sometimes they want a warmer tone, so mahogany is used, usually in the back of electrics, or as body wall of acoustics.

But the other obvious repair issues with lacquer also are there for Gibson, as well as the drying times.

I shot pretty much only polyurethane, mostly semi-gloss, for the twelve years I ran my refinishing shop. I could usually buff it with 0000 steel wool within two days and put on a thin coat of paste wax, and have a fairly waterproof finish that my customers loved. Fairly thin, and allowing the wood grain to show through, but still pretty resilient and tough.

Now, since I do mostly small stuff I shoot lacquer, but for my guitars it is 12-14 hand rubbed coats of Tru-Oil, since I don't have an oven system. My answer to the fast build of the lacquers used by the major guitar companies.
 
#25 ·
I wanted Blue Ice to look like frozen water. So I used ***************. I'm trusting my more-experienced Buddies on the durability, because I'm relatively new to Woodsmithery. As to lacquer: It's not available in Southern California. I've never used it. Shellac is my BFF because I can put as much or as little on as I want, depending on the luster I'm looking for. Too shiny? Easily knocked back. Not shiny enough? More, please. Shellac always gets topped with either furniture wax or Carnauba for protection. All this is with regard to indoor Things. Outdoor Things? I'm still trying to figure it out. Spar Varnish seems to peel off within a couple years. Spray-on Poly, on the other hand. Well. The "plastic factor" of Poly can be dealt with just as with Shellac.
I got my Envirotex a week ago, for the floor of the Buddy Bell, and am still trying to work up the nerve to use it.
I'm a little surprised about Gibson's choice of Lacquer for their guitars. Although they are electric. guitars. As I understand it, throughout history, a mixture of Shellac with some kind of ground semi-precious stone (Ruby, Garnet, etc.) has been, and still is, the traditional finish for acoustic instruments. i guess you'd know that, wouldn't you, Charlie? You're a guitar maker, right?
 
#26 ·
Mark: I'm no guitar maker…. the only one I built so far was from a kit. :) I do play a bit though.

You are correct about shellac being a traditional instrument finish for hundreds of years. However, in the last 50 years or so (someone here probably knows the history better than me) lacquer has been the dominant finish for guitars, both electric and acoustic. In recent years there has been a trend towards poly-type finishes in lower-end instruments, but as far as I know virtually all manufacturers use some version of lacquer on their top-end guitars.
 
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