Hello:
I need some help. I am reading up on finishes and the book I am reading talks a lot about varnish, but hardly mentions polyurethane. What is the difference between the two?
Thanks,
Jeff
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Polyurethane is varnish. Varnish is oil and resin among other things and in polyurethane the resin is polyurethane. Varathane, urethane, alkyd resins...they're all different resins used to make varnishes with different characteristics.
Lee
Furniture Carver
OK, since we are on the topic anyway...
What is wiping Varnish? and could you tell me some brand names that are common?
take care and the LORD bless
daleM
Wiping varnish is still a varnish, but it's cut down to make it thin enough that you can wipe it on and wipe it off. You could roughly compare it to taking one part varnish and two parts thinner and using it. The thing that gets a lot of people confused is that wiping varnishes rarely, if ever, say varnish on the can. Most of them say oil.
IMHO, this is to lead a less than fully educated consumer into some illusion of grandeur - since we already get told by cleaning products that furniture oil will replace the natural oils in the wood, which were never there in the first place. It hits us in our "ain't that quaint" button and we buy.
But as to brands, ZAR, Formby's, and Gillespies all make a wiping varnish. Most of the time it will say something moderately deceptive like "Tung oil finish", and likely the oil in the finish is Tung at that point - but don't confuse it with Watco or Danish oils, those are oil-varnish blends. They don't perform exactly the same, the don't build as well (in fact, you shouldn't try to build them) and have a higher oil to resin content than a wiping varnish, which would make a built up finish too soft to be practical.
" The State, in choosing men to serve it, takes no notice of their opinions. If they be willing faithfully to serve it, that satisfies." - Oliver Cromwell
Wiping varnish is thinned varnish. Watco is wiping varnish, Danish oil is wiping varnish. The varnish you buy is wiping varnish, it's just concentrated wiping varnish.
Varnish is resin, oil, drying agents, flattening agents and possibly some other additives. The solids in varnish, that which is not volitile, ranges from as high as 50% in the good stuff to as low as 15% in the watered down stuff like Watco.
You can make any varnish a wiping varnish by diluting it. Generally, just thin off the shelf products labeled varnish 30% to 50% with solvent. The solvent of choice is generally mineral spirits but you can use a faster solvent like naphtha if you can get it applied before the fast solvent flashes. You can play with the dilution rate because it's really tough to mess up and there is no hard and fast rule because the solids content varies so much product to product.
Lee
Lee Grindinger
Furniture Carver
You said that Watco isn't the good stuff, then what is. Can you build a durable finish with a wiping varnish?
Thanks,
Jeff
You can build with thinned products like Watco but as RW mentioned the formulations can be a problem. If the proportion of oil to resin is high the film will be soft. Exterior varnishes are "long oil" varnishes which simply means the amount of oil in a varnish is increased to help the film deal with movement. Exterior varnish is not the best of choices for indoor projects because of this softness and likewise, some of the "oil finishes" (read thinned varnish) are too long on the oil to produce a good film. Actually though, I think Watco is a decent blend for producing build if you have the tenacity.
If you want build the best way is with a brush. The next best way is with a sprayer and the way that applies the thinnest film is wiping. But, wiping is the most accessable to many people and certainly the most fail-safe means of applying varnish. If you want build forget the Watco and all of the "Oil Finishes". Go for a decent varnish and thin it.
Polyurethane...this is a marketing coup if ever there was one. There are many resins used in the manufacture of varnish. They all have different characteristics. Poly is the overall winner for abrasion resistance and heat resistance in the non-catalyzed finishes. But poly is about the worst varnish for application, it levels very poorly. Also, poly yellows with age becomming more opaque than some resins.
Alkyd varnishes level much better and resist yellowing. The actual difference between alkyd and poly for abrasion resistance and heat resistance is not significant if you're building furniture for adults. If the furniture is destined for a bar, a restaurant or a child's room I'd opt for the poly but for all else I go with the alkyd. The term "alkyd" refers to the means of extracting the resin and it's generally extracted from linseed oil or tung oil.
Although Watco will work I'd suggest you try a pint of a good alkyd varnish, even for wiping. McCloskey makes one called Heirloom, Pratt and Lambert makes one I've heard good things about and I'm sure there are many more out there. I was talking to Jeff Jewitt a while back about Heirloom and he said he's dropped it from his line in favor of a different brand, I can't remember the name of the varnish but Jeff's website is http://www.homesteadfinishing.com.
Well, I've probably over-spewed. I hope there's something in here that helps.
Lee Lee Grindinger
Furniture Carver
Phooey!
I disagree; I think theres a notable difference between wiping varnishes and oil varnish blends, but its probably not worth the argument.
Believe Jewitt has gone Behlen, the alkyd in that line is RockHard.
" The State, in choosing men to serve it, takes no notice of their opinions. If they be willing faithfully to serve it, that satisfies." - Oliver Cromwell
RW,
I agree, it's not worth an argument, but...
If you wish to discuss this tell me what these notable differences are between wiping varnish and oil varnishes.
Lee
Lee Grindinger
Furniture Carver
Lee, here is a good explanation of the difference between "thinned varnish" and "oil/varnish products along with which are which.
http://www.popularwoodworking.com/features/finish2.html
Both in content and performance, there is a fairly significant difference between the two. The "thinned varnish" is just that, a standard varnish that has been thinned by the addition of a thinner. However, in performance, once it it dry, it is just varnish although the film thickness is less.
"Oil/Varnish" is a mixture of standard varnish and a drying oil, thin somewhat with a thinner. Because of it additional oil content, it tends to penetrate the wood rather than sitting on the surface as a film. It frequently does not build well because the the high oil content but it does leave a close to the wood look and feel. It is less protective generally than standard varnish and leaves a soft, flexible finish.
FWIW, I agree with Howie. There's a vast difference between a varnish product to which one has simply added extra solvent to produce a 'wiping varnish', and a product that is specifically formulated to be heavy on oil and relatively light on varnish resins (i.e. Danish oils).
I view Watco and the other Danish oil products to be essentially a linseed oil finish with a light varnish "kicker" added for good measure. A finishing regimin using Watco would be exactly the same as one using boiled linseed oil. There would not be one iota's worth of difference between the methods of application available. The only difference would be the very slight varnish build that could be achieved with a Danish oil after the third or fourth (++) application, and a slightly higher sheen resulting from same.
Howie and BossCrunk and RW,
Reread my posts. I'm in complete agreement with Flexnor.
If you need an explanation show me where Flexnor and I don't agree.
LeeLee Grindinger
Furniture Carver
"Watco is wiping varnish, Danish oil is wiping varnish."
My only issue is with the above. The traditional Watco Danish Oil is an oil/varnish blend, not a thinned wiping varnish. "Danish Oils" are generally oil/varnish blends but some are thinned varnishes so a generalization that "danish oil is a wiping varnish" is only sometimes correct.
That said, Watco has recently begun to market a thinned wiping varnish. However, they do not refer to it as a "Danish Oil".
Other than that, your explanation was right on.
I think you're right. I look at wiping varnishes the way I look at reducing a 3lb. cut of shellac down to a 1.5lb cut - it's just a convenience in application of the product. Virtually nothing has been changed about the finished characteristics of the product. The build is just slower.
I sense swords being drawn so I'll spew first.
Flexnor's words about the difference between varnish and oil/varnish...
"One replacement was prepackaged oil/varnish blend. This didn't add anything to what was already being used, but manufacturers made consumers think it did by labeling their products with enigmatic names like Danish oil (made by squeezing Danes?), antique oil (just for antiques?), Velvit oil and Salad Bowl Finish."
He's saying it's a marketing trick! There is no real difference between varnish and oil/varnish other than a different proportion of oil to resin.
Flexnor's words...
"Wiping varnish is an improvement in protection and durability over boiled linseed oil and oil/ varnish blend, but the only thing new about it is the misleading name on the can. Anyone can make their own wiping varnish by thinning any oil-base varnish or polyurethane enough so it is easy to wipe on the wood."
Mine...
"Wiping varnish is thinned varnish. Watco is wiping varnish, Danish oil is wiping varnish. The varnish you buy is wiping varnish, it's just concentrated wiping varnish."
If you add oil to varnish it's still varnish. It's a crosslinked plastic. The term "oil/varnish" simply states there's a ton of oil in it.
You'll notice I never discuss oil as a finish. I do discuss "oil finish" and in my later posts I stress the difference.
What Flexnor tries to do is point out that much of this is marketing and that's what I'm trying to do as well. It's actually pretty simple. Varnish is varnish and nearly all "oil finishes" are varnish, that is a combination of oil, resin and other stuff to make it work.
Oh, as to building with Watco...I may have been wrong about that, it's been a very long time since I used it but in my defense here's my words...
"You can build with thinned products like Watco but as RW mentioned the formulations can be a problem. If the proportion of oil to resin is high the film will be soft."
Now, put your swords away.
Lee
Lee Grindinger
Furniture Carver
I sense swords being drawn so I'll spew first.
Flexnor's words about the difference between varnish and oil/varnish...
Sorry Lee, but I didn't post the link to Flexnor [sic]. I thought he did a relatively poor job of explaining the difference(s), or under-appreciates certain subtleties, between a varnish and an oil product to which a smidgen of varnish resin has been added.
Now, put your swords away.
You seem to be a bit of a touchy bloke. No swords were ever drawn as far as I'm concerned.
Relax, this isn't Breaktime, and nobody here is named Larry. My "phooey" is about as adversarial as I get on this forum. I kind of like it when people disagree. You get different viewpoints that way instead of a bunch of bobbing heads, and we tend to learn things, or at least, reassess what we used to think. At any rate, I dug out Bob Flexner's book Understanding Wood Finishing since I wanted to see what he had to say on this since I saw his name repeated. Take a look at pgs 70 & 71. You're still entitled to disagree. " The State, in choosing men to serve it, takes no notice of their opinions. If they be willing faithfully to serve it, that satisfies." - Oliver Cromwell
Yeah, well the sword thing was a misguided attempt at humor.
I don't have Flexner's book so you'll have to help me out.
I view it as more of a continuium instead of there being clearcut lines between when a product is called one thing or another, especially in this time of witch's brews that are popping up like wildflowers.
LeeLee Grindinger
Furniture Carver
OK. It's a guide to oil finishes, detailing things like protection, sheen, cost, color, properties . . . it differentiates between wiping varnish and oil varnish blends. There's pictures showing Watco in the oil varnish photo and some of the brands I mentioned in the wiping varnish photo. The commentary in previous pages seems to go to some length to differentiate between the two. But honestly, I spent all day at work arguing about why I was right. If you want to be right, you can have it for the rest of the day. " The State, in choosing men to serve it, takes no notice of their opinions. If they be willing faithfully to serve it, that satisfies." - Oliver Cromwell
RW, Cleveland Ed, and BossCrunk,
Fininshing terminology is very confusing. What I have tried to do is simplify it. Terms like "oil/varnish" and "spar varnish" are marketing terms and have no real meaning other that "this varnish has a lot of oil and is meant to be used as a penetrating finish" or "this varnish is meant for exterior uses". Different formulations have different characteristics and that's a very good thing because we need them for different uses.
But..."oil/varnish" is a seller's way of saying "Look, my product is special!" There is no defined point at which varnish becomes oil/varnish.
As to the spar varnish, Ed. This is another marketing term. Yup, I could take regular old varnish, add some oil and call it spar. It may or may not be decent spar varnish but it would be spar if I chose to call it that. "Spar" simply means "This product is intended for exterior use" It implies that it contains phenolic resin, is long on oil, has UV inhibitors and such but it's implied, not actually backed up by anything in the industry. Ed, the term "varnish" simply means it has resin, oil and other stuff that makes it work. It's a family of finishes, not just one particular formulation.
It's a matter of semantics, you guys. It's a matter of marketing terms. It's a matter of throwing another veil on an already confusing field. There certainly is a difference between a 30, 30, 30 mix of oil, varnish and spirits compared to a 50, 50 mix and if you want a penetrating oil finish that's great, I've used em' myself. However, if you went to five stores and asked for oil/varnish you'd probably come home with 5 different finishes.
Somehow this thread went from me defining poly as varnish and wiping varnish as varnish to trying (unsuccessfully) to define oil/varnish as varnish. I give up. You guys can be right. (wink, wink)
With that issue aside I'll offer this...
For a "penetrating" (actually, they all are in first stages) finish here's what I do. Warmed linseed oil or tung oil (not anything with the word "finish" in it) first, applied wet, wet, wet. Wipe it all off once the wood stops absorbing the oil. Let it dry for a few days, up to a week if it's cold or humid. Wipe it down with a clean rag every day, it will likely be oozing oil. Then apply wiping varnish. I make mine from off-the-shelf McCloskey's Heirloom thinned about 50/50 with mineral spirits. Two or three coats is all it takes but if you want more build keep on going. I'm not remotely suggesting this is a perfect finish, it's just how I do a non-build finish that's really easy and very durable. If you want the silky feel of wax, which is really nice as BossCrunk says, I use paste wax. Johnson's or Trewax, they are both good and very available.
LeeLee Grindinger
Furniture Carver
I think your formula is perfect.
>>As to the spar varnish...This is another marketing term
Unfortunately correct, Lee. But, when used in the marine trade, "Spar Varnish" was and is a specific product differentiated from exterior varnish. If you contact, Interlux, Woolsey, Epifanes or other manufacturers of marine specific coatings they will tell you that spar varnish is a varnish made from phenolic resin, tung oil, and gobs of UV protectors. The oil to resin content is very high. The intent is to produce a finish that is very flexible to deal with the large and rapid changes in environment and to stand up to the concentrations of sunlight. It is so soft, that it is not meant to be walked on and may be too soft to be sat on without leaving an impression of the fabric.
Their standard exterior varnishs may or may not contain phenolic resins and do not contain as high a percentage of oil and generally have less UV protectors. This makes for a somewhat harder coating that will take more abuse.
The problem is that the consumer finish manufacturers have usurped the name "spar" in an attempt to sell to the non-marine trade. In a recent test performed by some folks in the marine trade, Minwax "Spar" vanish was the first to fail and McCloskey Helmsman was the second. Both failed within a couple of months. Other marine spar varnishes lasted over a year.
I need to make this point too. Adding more oil after a varnish is manufactured, does not make it a "long oil" varnish. As you have said, varnish is made by mixing and heating resin and oil. Once it has become varnish, it is a new compound and no longer can it be separated into it components. Adding oil after it is varnish just makes it an oily vanish.
Howie, let's say you're formulating a gallon of varnish. To the original recipe you add an additional pint of tung oil then cook it all together. To a galllon of varnish that has already been cooked following the original recipe you add a pint of tung oil. Do you think there would be a difference in the films from the two? What would they be?
I honestly don't know the answer.
Lee Lee Grindinger
Furniture Carver
My guess, if you will allow it, would be that the concoction to which you added additional oil but not heat would behave very differently than the one to which you added the same amount of additional tung oil then proceeded to cook it. My suspicion is that the uncooked formula would have a longer drying time and a softer finish. But this is only a guess. I don't cook my own varnishes, but I'd like to know more about it.
If heat was not crucial to the process, then I suppose it wouldn't be used in the first place.
Edited 1/10/2003 2:38:45 PM ET by BossCrunk
A nice informative discussion guys. Informative both for technical details and telling me that I was not off track when I decided that there was a lot of confusion caused by the marketing efforts of various manufacturers. It's a mystery, cloaked in an enigma .. lol.
Boss and Lee, I think you are correct that for most practical points, there is probably little difference by adding additional oil after the cooking process. I too, would guess it would be softer and probably less durable. I've used lots of marine coatings and spoken to many of the manufacturers over the years but never have I asked them this question.
The basic conclusion is that there are many different products out there but many of them are only differentiated by their marketing claims. Varnishes seem to be the finishes that are most often combined or "bastardized" to create new marketing products.
As Flexner and others have stated, there are true or real oils like tung and linseed oil--within this group are the polymerized tung oil and linseed oil, then there are oil/varnish products (Marketing named Danish oils, teak oil, tung oil finishes, etc), thinned wiping varnishes (Again marketing named danish oil, tung oil finish, etc), true varnishes, (short oil interior, long oil exterior), polyurethane varnishes (true varnishes containing some urethane additive to increase scratch and heat resistance) and marine spar varnishes (phenolic resin, tung oil and UV inhibitors).
Now rewind a few days to when this thread was all of a couple of posts long. Who'd a thunk this would generate so much debate. As to the mass confusion issue, I couldn't agree more. But to solve it, we'd have to get FDA labels involved, and then we'd just all give up! BTW, I didn't argue with a single person today. I'm gonna mark the calendar.
" The State, in choosing men to serve it, takes no notice of their opinions. If they be willing faithfully to serve it, that satisfies." - Oliver Cromwell
I am trying to pick a finish for my 150 year old 8" wide poplar floorboards. So I am more than happy with the interest and information this thread has generated.
If I go with an oil/varnish penetrating finish and later observe that it was inadequate for my needs, does anyone see any problems with simply applying a couple of coats of varnish over it? I won't wax the floor, so that won't interfere with adhesion.
No problem with applying an oil based poly over a cured oil/varnish. Just clean it up and scuff sand lightly.
Lee,
I like your point about these formulations resulting in more of a continuium than any clear cut lines. However, the following really caught my attention, so maybe I can get your feedback:
If you add oil to varnish it's still varnish. It's a crosslinked plastic. The term "oil/varnish" simply states there's a ton of oil in it.
My perception when using oil/varnish mixtures is that the addition of the oil eliminates some of the properties of the varnish. I don't see the resulting product as being "varnish" any longer. I don't see it as a varnish whose proportion of oil has just been increased either. The whole protective quality of the varnish is so diminished. I love the oil/varnish mixtures, and I see the varnish as augmenting the oil in terms of protection. But I really wonder about any continuum in this mixture. I always thought there there was probably some production process applied to the varnish ingredients - could be heat, pressure, anything - that converted the oil in the varnish into something different from the oil as it existed when it was added.
Let's think of the spar varnish. It's commonly explained as being varnish with a higher proportion of oil. If someone were to take regular varnish and add some oil, it wouldn't perform as spar varnish at all.
Ed
A continuum is a reasonably decent concept, but in my view a product is a varnish when you get visible build in one, or perhaps two, coats (and this is certainly possible even with very thin, so-called "wiping" varnishes).
Danish oils certainly don't fit this criteria and, in fact, fit every other criteria for a simple oil finish. The added benefit of a small amount of resin can be a plus unless the craftsperson wants an absolutely authentic oil finish. However, I doubt most of us could see the difference between a plain linseed oil finish and a 3 to 4 'coat' Watco finish. And certainly not after applying a wax topcoat, which would be more or less routine.
The sad part of the Danish Oil Saga as I like to call it, is that the manufacturers became the instrument of their own undoing with serious woodworkers - they marketed the product as "easy" and "foolproof" which was a turnoff to serious craftspeople because they assumed the product was only suited for beginners or the uninitiated. What a shame. A patiently applied Danish oil finish followed by an even more patiently applied wax topcoat is really stunning. Again, it's just a slighly more modernized form of an oil finish with all the aesthetic benefits and with a few of the drawbacks eliminated or at least limited (drying time and 'protection' issues).
Edited 1/10/2003 7:29:19 AM ET by BossCrunk
Thanks guys, it is really quite clear to me now.But just one question, "Is it gloss or satin....?"
take care and the LORD blessdaleM
If you have spray equipment, you may consider using "conversion Varnish". This is a product that I have used for 3 years and love. It is a 2 part system, meaning you add a catalyst to. I use Rudd or the Sherwin Williams brand. It drys in about 20 minutes similar to lacquer, but is much better than lacquer.
I have a simple rule for finishes on my indoor woodworking projects -
Any piece that has a top that can have something setting on it, I use poly. Elsewise, I use lacquer. I generally wipe the poly (thinned) and always spray the lacquer. I use Deft brand for both cause it is readily available and fairly easy to use. Working with either finish can achieve the look I desire. Lacquered pieces sometimes get a shellac undercoat.
I deviate sometimes for small pieces by using thinned 100% pure Tung Oil or shellac and wax.
I stay away from so-called 'prepared' finishes.
Never had the skill to do french polish. Tried it once. Total disaster.
PlaneWood by Mike_in_KatyPlaneWood
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