Why is Poly Varnish Bad

[John TenEyck]

I keep reading folks say that poly varnish is good for floors and not furniture. Why? I've used poly varnish on various furniture projects, and some floors, for more than 25 years. I've never had a problem with any of them. I've heard people say you can't rub out poly varnish finishes. Not true. I've done it several times. I just saw an article in an old issue of FWW, FWIW, where the author described his process for doing so - on furniture. I've heard people say poly doesn't stick well to anything, including itself, yet I've never had a problem with it peeling. I've heard people say it's not a hard finish. Maybe some are soft, but many are plenty hard - if you can rub them out they have to be.

The only problem I've ever had is on a sliding glass door where the sun finally caused it to blister and crack, but I'm betting that would have happened on nearly any clear film finish.

So please give me some facts about why poly varnish is not a good choice for furniture. Everyone is entitled to their own opinion, but statements that come across as facts should be supported by them.

[Scott Holmes]

John,

Poly is not BAD. It's not as GOOD as some of the other varnishes.

Clarity - not as optically clear as some of the other resins. e.g. alkyd and phenolic.

Rubout properties - not as hard as either alkyd, hard and clear; or phenolic very hard and amber.

Adhesion properties - Poly is best applied when surface is sanded between coats... the other varnishes will adhere much better than poly if the surface is not sanded between coats. All varnish adhere better if a light scuff sanding is done between coats.

Hardness - Many polys have alkyd resin in the mix to make them harder. Poly can be rubbed out or buffed out; the draw back to poly is that it is more difficult to get an ultra high gloss with poly it is about as high a gloos as possible once it's dry. Getting it higher gloss on poly is not easy. Getting a harder varnish to a higher gloss is much easier.

UV stability - urethane resin varnishes are very very susecptible to UV damage. If you want to know why they make exterior poly one word ...profit. Poly is much less expensive to manufacture and will not last in UV so they sell it over and over again. In Houston, TX there is a good chance exterior poly will not last 6 months in direct sun. Phenolic resin varnishes are UV stable.

When it comes to floors poly wins hands down. It's number one trait is extreme abrasion resistance. Harder varnishes will scratch easily; poly will not. That's where the rub out diffculties comes in. The harder the finish the better you can get uniform scratch patterens and that's really what you get with an high gloss; ultra fine, uniform scratches. Poly abrades and doesn't scratch as well.

[Howard Acheson]

The biggest problem I have with poly varnish is that it is not as clear as a non-poly varnish. There is always a slight "cloudiness" to it. The issue is appearance.

BTW, the reason for the splitting and blistering is that urethane is attacked by the UV in sunlight. It rather rapidly gets cloudy, more amber, and then begins to crack and peel. Adding UV inhibitors to it does not add much to its longevity. That's the reason true marine varnishes do not contain urethanes.

[Jim Becker]

Scott is right..."bad" is the wrong word. I would say that polyurethane is appropriate for some types of projects, but in general, it's not an ideal furniture finish as compared to other available options. Howard and Scott both point out correctly that many poly varnishes tend to have less clarity and many also cure to a more "plasticy" look. Scott has provided a number other areas when this type of finish presents challenges.

Please also be aware that water borne "poly" is not the same animal as oil based polyurethane. All water bornes with very minor exceptions are acrylics and those that have "poly" on the label merely have some polyurethane resins added to the mix to presumably provide some of the properties that the resin imparts in finishes. The majority are not even close to oil based poly in abrasion resistance which is the primary reason to use a polyurethane finish. (There is a class of water borne products which are oil-emulsified formulas...the water borne Minwax floor finish is an example...and these are closer to an oil-based product in performance because once the water carrier evaporates, the solvent-based finish cures normally, but with a lower VOC)

[Howard Acheson]

I had meant to add that another negative I have with oil based urethane finishes is that they tend to become more amber faster than non-poly varnishes. Again, it's an appearance issue.

[John TenEyck]

Thanks for the replys, everyone. Some good points and observations. I always like to look at real data to see if what people say is borne out by facts, so I looked for any data to compare the optical clarity, light transmission, etc. on various resins, but came up empty. In my own experience, again, no facts, I've seen some polys which appear somewhat cloudy and plastic-like after you put on a thick film, but I've seen others that are incredibly clear, like lacquer, at least to me.

222436

There are some new exterior WB polys that are getting very good reviews for durability - comparable to marine varnishes. I haven't used them since I've had such good luck with Epifanes so I can't say, and perhaps they don't contain much urethane, as one of the posters noted.

FWW did a comparison of WB finishes a few years ago, and they choose a poly based product as the overall winner - GF's Hi Perf. Poly if I remember correctly.

Poly is not appropriate for all applications; no finish is. But I guess what bothered me the most was the blanket statement that poly should be used on floors only and never on furniture. If that's the poster's opinion, that's fine with me. But it would be fairer to say that it is an opinion, and not in such a way that it sounds like a fact. Maybe that's just how I interpreted - but I doubt it since I've seen at least one of poster ask for clarification.

Again, thanks for your responses.

John

[Scott Holmes]

FWW loves "Poly" because the manufacturers are a large advertiser...

Did you notice that they didn't even test alkyd or phenolic resin varnishes?

[Prashun Patel]

Humbly in the presence of the pros, I'll offer my hobbyist experience:

Poly does not let its optical shortcomings vis-a-vis other varnishes be known unless you build it up. In an oil/varnish blend, it does a great job IMHO. But that's a type of finish that's not designed for super durability/abrasion resistance anyway. I basically use poly in some OV blends because it's cheaper than other varnishes, and it's shortcomings are moot when the coat is thin.

It is also available in 1/2 pints.

I mean, the only reason I use it is bkz it's economical and readily available.

If you visit the turners' forum, you'll notice it's one of the most popular finishes.

There's a time and place for it, is all I'm saying.

[Jerome Hanby]

You can look at that in more than one way. If manufactures of other types of finishes don't advertise in FWW you could also conclude that they don't think that FWW readers are interested in their products and it would make sense that FWW wouldn't devote space to reviewing products in which their readers are not interested. It's easier and cheaper to hitch a ride on your advertisers market research than doing your own.


FWW loves "Poly" because the manufacturers are a large advertiser...

Did you notice that they didn't even test alkyd or phenolic resin varnishes?

[Ole Anderson]

I gave up brushing poly long ago for all the reasons stated. BUT I moved to a wipe-on poly (MinWax) and it is a whole different world. Goes on super fast, dries much faster than brushed varnish, there are no runs or bubbles and no brushes to clean. Sand the bare wood to a 220 grit (then stain) then I do 3 or 4 coats using half of a Scott's blue shop towel, one after another as soon as they dry, no sanding between coats due to the lack of film thickness until the last coat. In between coats I store the wet blue wiper in an old margarine container with some wipe-on poly. 24 hours after the last coat I go over it with 400 grit PSA paper on an automotive hard foam block and finish it with a coat of Johnson's wax. It is not quite an oiled finish, but is isn't an obvious film finish either. Best of both.

[Bill White]

I guess that I've been an anti-poly finish dope just because I try to work with more classic finishes as a choice. Maybe that I'm a bit of a dino, but I try (TRY) to mimic some of the wonderful finishes achieved by the old masters. Neander? Oh well....
I'm in the midst of a wiping varnish as I post. Now at 6 coats with rubbing in between. Not there yet, but I'm workin' on it.
BTW, walnut is a beast to finish without some elbow work.
Hey! It is just the way I work. Do ya see any poly at Williamsburg? JAG...(just ask George).
Bill
ps:
I'm probably gonna get some hate mail from MW (or Craftsman if they even pay attention). So be it.

[John TenEyck]

FWW loves "Poly" because the manufacturers are a large advertiser...

Did you notice that they didn't even test alkyd or phenolic resin varnishes?

The test I was referring to was for WB finishes, so that's why no alkyd or phenolic resin varnishes were tested. At least I don't know of any WB ones, which brings up an interesting point. Why not? Is it technically not possible? Or is it a matter of those companies not trying to produce them for whatever reason? Perhaps they recognize that more modern resins are superior, or easier to produce, or have higher profit margins. I don't know, but I find it curious that they haven't moved to develop WB versions of their products.

[Mike Monroe]

"Do ya see any poly at Williamsburg?"

If poly was around back then, I'd have to guess you would see it.

[John TenEyck]

"Do ya see any poly at Williamsburg?"

If poly was around back then, I'd have to guess you would see it.

Exactly right. They didn't have table saws, or even electricity back then either. Now that we do most people like both. I would bet that if poly, or lacquer, or any of the new finishes had existed back then that's what you would see on the stuff they made.

[Jim Becker]

The test I was referring to was for WB finishes, so that's why no alkyd or phenolic resin varnishes were tested. At least I don't know of any WB ones, which brings up an interesting point. Why not? Is it technically not possible? Or is it a matter of those companies not trying to produce them for whatever reason?

Nearly all water borne finishes are acrylics...they don't use traditional resins. Those that have poly in the name do have some polyurethane resin added to the formula, but it's not really the same kind of product as an oil based varnish that is based on polyurethane resin. Remember, with the oil based products, when they are "cooked", the ingredients incorporate together to create a new substance...the varnish. With the water borne products, different types of ingredients are used to create the acrylic polymer that is the finish. Those with poly added don't perform like their oil based counterparts. But there's more as I explained in my previous post...there are some water borne products that are emulsifications whereby a solvent-based finish is suspended in the water carrier. In that case, such as the Minwax floor finish I mentioned, the performance is more like the "pure" oil based product because it is an oil based product. 'Just one with very low VOC.

[George Octon]

The issue of clarity:
I have never heard (after 30 years) that polys are less clear. In fact different brands have different colors. Some are very clear. On furniture you would usually be using satin which are naturally cloudy. Pigment stains are "cloudy" too and most people use them. To use a clear gloss, you would have to rub it out. What level of perfection are we even aspiring too here, let alone achieving. Could the negative opinion purveyors of polyurethane even the the difference?
I think the original poster here makes a good case that the negative feedback for polys he's heard , like most pontifcations you hear.was largely bullcrap

[Prashun Patel]

George, to each his own. My experience is that there is indeed a visual difference on built up finishes (at least the way I apply it which might be less that professionally). Lately I've been finishing my turned bowls with built up varnishes. I can easily pick out the poly ones and I do indeed find them to look like plastic.

Uv resistance notwithstanding, the diff is largely aesthetic. If people like the way it looks then go for it.

[John TenEyck]

Some searching showed that water based alkyd varnishes do exist. I'm not sure why Scott didn't point that out to me, maybe just being kind, but his point is interesting in that none were included in the FWW test of waterborne finishes. Nor do I remember any of those manufacturers complaining to FWW that they weren't included or, if they did, it wasn't published. I also find it curious that they don't advertise their products in FWW or any other magazine I look at, including one targetted at professionals. Sherwin-Williams is one of those companies, and they do sell to consumers, but maybe they target those products only towards pro shops. Still curious.

[Scott Holmes]

My favorite waterborne finish is pro-only from Sherwin Williams. SW Paint stores can't even order it for you. Only "Chemical coating" sells it. KCMA passed...

That's one reason I don't talk about it. It's not readily available; it's only available in 5's and 55's (gallons that is)...

[Tim Howell]

I am using Sherwin Williams Fast Dry Oil Varnish - A66-300 series - Alkyd - and their sanding sealer to try and fill the grain.. They both dry quickly and the clearity is shockly clear, like glass on the high gloss. I used Poly before on my progects, but it's SW Alkyd from now on!!! The junky piece of B-2 Red Oak plywood I'm working on has the SW on the bottom for testing and practice - I couldn't believe how the grain popped out w/ the SW vs the poly. It's crystal clear w/ a little amber vs hazy and plactic looking w/ the poly. I have been brushing, but its 24 x 72 so I'm going to try my old spry gun - if it still works after 35 years in a box.

[Scott Holmes]

I have used Sherwin Williams Fast Dry Oil Varnish many times. My favorite alkyd resin varnish, P&L #38, is difficult to get locally so the SW is the repalacement.

Sherwin Williams Fast Dry Oil Varnish has one trait I don't like.

After 24 hours or so, if you lightly sand it (to smooth it, it's not required for adhesion like poly) then wipe the dust with a rag damp with mineral spirits the surface tends to get a bit sticky. After a couple of days drying this isn't an issue.

Conclustion: This is not a good varnish to make into a wiping varnish.

[glenn bradley]

FWW loves "Poly" because the manufacturers are a large advertiser...

Did you notice that they didn't even test alkyd or phenolic resin varnishes?

FWW content being influenced by their advertisers!?! Nooooo. :D

[John TenEyck]

So what's the downside of SW et al not selling to the consumer? Profit can't be it. My former company would easily double or triple the price to small volume customers to make up for any hassle of dealing with them. Protection of industrial/commercial customers? Doubt it. A guy in his basement shop's not going to steal business from them. Very strange to me. Scott, I see a new business opportunity for you. Just buy the stuff in 55 gal drums and repackage it to all us SMCreekers under your own label. You'll make a tidy profit with very little work.

[Rich Engelhardt]

Just buy the stuff in 55 gal drums and repackage it to all us SMCreekers under your own label. You'll make a tidy profit with very little work.
LOL!

You ever try to draw or pour off material out of a drum?

I did - quite a few times...

[Sam Murdoch]

It's quite a haul for me to get to our nearest and kind of pathetic Sherwin Williams store but you've intrigued me with the 2 endorsements of the Sherwin Williams Fast Dry Oil Varnish .

Is this available in a matte finish and if so does the matte finish level out nicely and clear?

What does "fast dry" mean if after 24 hours it is still easily softened with mineral spirits?

I would like to find a viable - equally durable substitute for Waterlox. Could this be it?

Thank you.
Sam

[Scott Holmes]

I think it's satin and gloss only no matte or dead flat. A quick buffing with steelwool will make it matte pretty quickly.

"Fast Dry" it dries to the touch < 1 hour. The curing process takes a month or so. This is true for all varnishes, excluding conversion varnish or varnishes that have a post mix crosslinker or catalyst.

Sherwin Williams Fast Dry Oil Varnish will dry to the touch very quickly; but it tends to soften even 24 hours later if you rub it too much with mineral spirits...

I would NOT agree that it's a replacement for Waterlox. Sherwin Williams Fast Dry Oil Varnish is an alkyd resin/linseed oil varnish and WaterLox is a phenolic resin/tung oil varnish. The WaterLox will be harder, darker, darken more, be more UV stable and more waterproof than the Sherwin Williams Fast Dry Oil Varnish.

On lighter co;ored woods the Sherwin Williams Fast Dry Oil Varnish will be clearer, impart less color, be less likely to yellow over time.

Durablity --- I would say WaterLox wins that test, although the Sherwin Williams Fast Dry Oil Varnish is very good.

[Sam Murdoch]

Valuable info Scott. Thanks very much.

[Howard Acheson]

>>>> I would like to find a viable - equally durable substitute for Waterlox.

The closest you will find is Behlen Rockhard. Like Waterlox Original, Rockhard is made with a phenolic resin but the drying oil is linseed oil rather than tung oil.

[Sam Murdoch]

Thanks Howie. Is it really "rockhard"? Any compromise? Surprisingly I can get Behlen easier (locally) than Waterlox or the SW varnish.

[Ole Anderson]

I gave up brushing poly long ago for all the reasons stated. BUT I moved to a wipe-on poly (MinWax) and it is a whole different world. Goes on super fast, dries much faster than brushed varnish, there are no runs or bubbles and no brushes to clean. Sand the bare wood to a 220 grit (then stain) then I do 3 or 4 coats using half of a Scott's blue shop towel, one after another as soon as they dry, no sanding between coats due to the lack of film thickness until the last coat. In between coats I store the wet blue wiper in an old margarine container with some wipe-on poly. 24 hours after the last coat I go over it with 400 grit PSA paper on an automotive hard foam block and finish it with a coat of Johnson's wax. It is not quite an oiled finish, but is isn't an obvious film finish either. Best of both.

Just having said this, I ended up brushing poly for my bedroom rehab project. I am pulling all of my painted base and door casing (about 180 lineal feet) as well as two 4' bifolds and replacing with Oak, stained MinWax Red Oak. To match what I have done in the rest of the house over the years (the bedroom was the last holdout) I decided I needed something heavier duty than wipeon, so I went with 2 coats of gloss MinWax poly, followed by a coat of Satin Poly, sanding 220 between coats as recommended. Besides the more durable finish, I was encouraged after following the advice in the Scott Holmes video regarding brush prep and technique, including pouring the varnish into a 4" roller pan instead of wiping the brush on the edge of the can. Thanks Scott. I tried a final coat of wipeon satin after the 2nd coat of gloss without sanding, but the satin just didn't work, so I sanded again and brushed an unthinned final coat of satin. Nary a dust nib or bubble. I let my air cleaner run the whole time to keep the air clean and circulating. It may be my imagination, but I recall the older MinWax varnish a bit thicker and needing thinning more so than what I just purchased.

http://www.youtube.com/watch?v=DZW8dqI2zb8&feature=youtu.be

[Mark W Pugh]

John,


UV stability - urethane resin varnishes are very very susecptible to UV damage. If you want to know why they make exterior poly one word ...profit. Poly is much less expensive to manufacture and will not last in UV so they sell it over and over again. In Houston, TX there is a good chance exterior poly will not last 6 months in direct sun. Phenolic resin varnishes are UV stable.



Along these lines, I have a fiberglass front door that needs to be redone. It gets A LOT of hot direct sunlight. What should I use to finish it with?

[Alan Lightstone]

"Fast Dry" it dries to the touch < 1 hour. The curing process takes a month or so. This is true for all varnishes, excluding conversion varnish or varnishes that have a post mix crosslinker or catalyst.

Sherwin Williams Fast Dry Oil Varnish will dry to the touch very quickly; but it tends to soften even 24 hours later if you rub it too much with mineral spirits...




Scott:

Did you ever find a solution to the softening with mineral spirits after even 24 hours when you try to sand it? Does waiting 48 hrs solve the problem? Or sanding it with water/dishwashing liquid instead of mineral spirits? Or something else I'm not thinking of?

Is this why you said it doesn't make a good wiping varnish? So, am I right in assuming you brush it on?