Hokay –
Since my local supplier has decided to discontinue carrying Minwax’s wipe on poly, the characteristics of which I really like for many applications, I decided to mix my own. I used the accepted 33% BLO, poly and mineral spirits recipe and sure enough, the initial working properties are quite similar to the commercial mix, BUT….
The resulting finish a) is not dry enough to sand after sitting overnight (as the Minwax inevitably was) or even after sitting for a couple of days, and b) even after the finish is seemingly dry to the touch, it still appears to be quite soft, and when sanding it, 220 paper quickly gets covered with spots or nubs of finish, rendering the paper next to useless long before the grit is worn out.
So what’s going on here? Does the Minwax have a dryer in it (like japan dryer)? Would the addition of same significantly shorten the storage time of the mix? If so, why doesn’t this occur with the commercial mix?
Browsing a bit in this forum using the search function, it appears that some advocate wiping the piece after 10 – 15 min., something I never had to do with the commercial mix, and consequently have not done with the shop mix…..comments?
Lastly, is there anything that can be done with a piece already finished to fix the apparent lack of finish hardness? (I suspect I already know the answer to this, but just maybe one of you magicians can help here…)
Thanks in advance.
Replies
The Minwax wipe-on poly is just polyurethane varnish thinned with mineral spirits. It's not an oil/varnish mix (which is what you got when you added linseed oil). Varnishes (wiping or otherwise) don't need to be wiped off after application; oil/varnish mixes do.
-Steve
Hi Steve.
Thanks. But if this is so, what about Waterlox, which I have been using a lot recently? It does have oil (tung) in it, and doesn't need to be wiped after application.
No Waterlox does not have tung oil in it, except as an ingredient used in the chemical reaction that makes the varnish. Waterlox is just varnish, not an oil/varnish mix. It too is (its own) victim of marketing that wants to give special properties to tung oil.
This is particularly ironic, since tung oil as a pure tung oil is a pretty lousy choice for finishing, being very slow drying and hard to apply. If rushed it can develop a "frosty" appearance. It also requires 5-6 coats, sanded between each, to create an even satin sheen. It's protective qualities are about as minimal as boiled linseed oil (BLO) which dries faster.
But as an ingredient in varnish it contributes to good water resistant varnishes, including tradtional long oil spar varnishes, and the Waterlox family of varnishes. That's why Waterlox does not need to be wiped off after application, while oil/varnish mixes, such as Watco do need to have all excess thoroughly wiped off.
At the Waterlox site, they say specifically that their finishes contain tung oil. What gives?Denny
"What gives?"
Read the rest of the thread. Table salt contains both sodium, a highly reactive metal, and chlorine, a toxic gas. You don't get salt just by mixing the two together.
-Steve
Steve
Just wondering about the "bloxygen" solution to keeping the waterlox from skinning over. How do you use the stuff. I must admit I have used old marbles to top up the jars. Maybe its time to upgrade??
Any experience using this product?
dan
I follow the directions on the can. ;-)
I just squirt some of the gas into the container; it seems to work, although if I leave the can alone for several months I still get some skinning. You have to be careful not to squirt the gas with such force that you splash finish all over the place.
I also tried storing Waterlox in those collapsible plastic containers that photographers use. That was a disaster. For unknown chemical and/or physical reasons, the containers continued to auto-collapse after filling, causing finish to leak out and get all over everything. The containers I tried didn't seal all that well; it may have worked better with better containers.
-Steve
The Waterlox MSDS lists the ingredients they use to produce their varnish. Varnish is made by mixing a resin and a drying oil and then heating it to a certain point at which the two combine into a new compound called varnish. Thinners are then added to make it easier to apply.In the case of Waterlox they are saying that they use phenolic resin and use tung oil as their drying oil. When heated and combined, the resin and oil inject some of their individual characteristics into the resulting compound. It's like bread. Bread is a combination of yeast and flour. Once mixed and heated the result is bread. The yeast and flour are no longer recognizable as individual components but characteristics of the particular yeast and the particular flour affect the outcome of the bread.If you looked at the MSDS of other varnishes, you would find the same components. There would be a resin (phenolic, alkyd or urethane) and a drying oil (linseed, tung or soya).So, the Waterlox MSDS just confirms what has been said. Waterlox is a varnish, pure and simple. While made with tung oil, it's not tung oil.Howie.........
Edited 5/28/2008 3:12 pm ET by HowardAcheson
Howie, I understand what you're saying. What I was having difficulty with is some say it does NOT contain tung oil, but the data sheet says it does. Wouldn't I be more inclined to buy what the data sheet says?Denny
>> some say it does NOT contain tung oil,We're hung up in semantics. Waterlox does contain tung oil as component of their recipe for varnish. But once it's "cooked" it's a varnish, not a varnish and tung oil product like Watco or Minwax Tung Oil Finish, or other oil/varnish mixtures.Waterlox may have chosen tung oil as their drying oil because it is slightly more water and moisture resistant than linseed and soya oil. It also tends to become slightly less amber over time. However, Waterlox uses phenolic resin which is quite a bit more amber than alkyd or urethane resin but it is also harder than either of the others. In general phenolic resin and tung oil are more expensive than other resins and oils. So if a finisher wants hardness and water resistance as his primary characteristics, Waterlox is good choice. But, he will have to put up with the higher price and considerable amber tone. There's always pluses and minuses with each finish.Howie.........
Edited 5/27/2008 11:22 am ET by HowardAcheson
Ah. Okay.
I first used Waterlox in 1960 when, as a young squirt, I helped my Dad build our house. We put in a wide plank oak floor and knotty pine walls, and all of it was coated with Waterlox. Seems to me that held up for about thirty years before he recoated it, again, with Waterlox.
I've used several of their products. I find them easy to use and outstanding resistors of abrasion and most solvents. While I use other products too, I always keep a couple cans inventory in stock of at least three of their formulations. For me, it's the "no surprise - old reliable" I can always fall back on. Denny
"What I was having difficulty with is some say it does NOT contain tung oil..."
How about this:
Waterlox does not contain "free" tung oil in addition to the tung oil that has been chemically incorporated into the varnish.
Better?
-Steve
It contains it.
It doesn't contain it.
Well, it sort of contains it, but .....
LMAO --- We sound like politicians --- LMAODenny
Denny,
You got my vote!
Michael
Edited 5/27/2008 5:24 pm ET by pzaxtl
You got my vote!..........
My fellow Americans, I promise EVERYTHING !Denny
Having started this thread, and having learned what the cause of my problem was/is, I thank all for your contributions.
Now I'll take it in a slightly different direction: What are the advantages/disadvantages of an oil/varnish mix over a straight varnish finish?
I'm not seeing any great enhancement of grain or figure with the addition of the oil, and the neccessity of wiping after application seems to me to be a PIA - there is the extra time involved, the care of and disposal of more oily rags, and, to a certain degree, the waste of materials - put it on, take it off, throw it away....
So why bother?
Looking forward to further education.
If you aren't getting any benefit (grain deepening, etc.) then don't do it. It is basically a Watco finish application, and requires a topcoat for durability.
BUT there are times it does enhance the finish and is certainly worth the small amount of time and materials it requires.Gretchen
Thanks Gretchen
That's basically my take - why bother.
It's also my guess that it may be worth the trouble with very highly figured woods, but not with run of the mill stuff.
I've got a chunk of curly birch that I used part of to make a jewelry box top for my daughter, and I wasn't totally pleased with my efforts making its figure "pop" (don't remember now what techniques I used....) so the next time I use some of it, I'll probably try oil, but I doubt I'll use a combination like what we've been discussing. I'll probably just oil it, let that dry, and then topcoat.
That's not exactly what I said. IF it doesn't suit your project, there is no need for it. You sort of dismissed it as "never", in my opinion. I have used it often with nice results. Some woods just don't take the oil, and maybe that is what you have been using.
And as you are saying, just oil will also do the job. With a topcoat. Otherwise you will have a dust magnet.Gretchen
Gretchen, I agree with your comments. An oil/varnish finish is very nice on darker colored woods like cherry, mahogany and, most of all, walnut. These woods look particularly nice with in-the-wood finishes rather than high gloss/high build film finishes. They are also nice when you want the look and feel of the wood. Oil/varnish is not my idea of a good finish for light colored woods like pine, birch, beech, etc.What gets forgotten is that there is not one "best" finish for all situations. Finishes are chosen for whatever the finisher feels are the benefits of each type of finish. Sometimes the "look" is the primary objective and at other times, the "durability" becomes the primary need. Unfortunately, there is not one finish that meets what everyone looks for in a finish.Howie.........
Ah - sorry you got that impression. I try never to say never....
But in the project in question (cherry, in fact), I do find it to be a "why bother" in this particular instance.
I'm still (obviously) mounting the finishing learning curve, mostly trying to find out why poly is so frequently disparaged in these forums. So far, other than gloss poly, which I have never liked, I have not come to the point of discarding poly from my bag of tricks (such as they are....)
I've tried shellac with mixed results, have used Watco in the past, with and without topcoating, am currently in the midst of a long project of ~ 40 pcs. that are all getting Waterlox.
The original post here came from an attempt to match coloring (simple aging under poly) when replacing a couple of large, removable panels covering the liquor supply in a urethaned cherry bar (night time lock-up). I thought perhaps the oil would help age the newer cherry. It didn't - not really, nor did it seem to appreciably enhance depth or figure or grain over a simple urethane finish, so live and learn - next time I won't bother.
I'm tired of trying to color cherry to match older surroundings. My current mantra has become "Patience Is A Virtue", and I will only start staining/glazing cherry again under extreme duress.
Why is oil based polyurethane varnish disparaged on these forums? Basically, poly's advantages are mostly relevant with respect to floor finishes, where the increased resistance to abrasion is certainly a plus. Very little furniture is subject to that kind of abrasion. By poly, I'm thinking of the single part DIY oriented products available everywhere. These are typcially varnishes made with alkyd resin modified with polyurethane resin, Uralkyd varnishes might be a more accurate name. There are two-part pure polyurethane finishes, with superior characteristics depending upon which of the many varieties of polyurethane they encorporate but these are not for run of the mill furniture applications.
With respect to other properties, water resistance, chemical resistance, heat resistance advantages of poly are very small or non-existent, not at all likely to be siginifcant it the choice of a finish.
But there are disadvantages that come with the poly. In my mind, the most important is that it is more difficult to rub out to an even sheen. This makes sense when you realize that rubbing out a finish as a process of using a series of abrasives to achieve the desired sheen. Poly resists abrasion.
Poly is more subject to adhesion difficulties. That's why if a shellac sealer is needed, it must be dewaxed shellac under poly, but with tradtional resin varnishes shellac with wax will also work. That's also why it is more important with poly to properly sand between coats to achieve a mechanical bond, especially outside a narrow time window where some cross-linking between coats can occur.
Poly isn't quite as clear as traditional resin varnish. This shows up when the total film thickness of the poly starts to get large--and accounts for the "plastic look" often attributed to poly. This is a subtle effect of course, mostly noticable at only certain angles of viewing.
DIY poly is also more subject to damage from UV light, making it less desirable as an exterior varnish.
The other point to be made is that poly is not one iota easier to apply than traditional resin varnishes. Exactly the same techniques of brushing or wiping apply.
Thanks, Steve, for all your contributions.
Your most recent succinctly sums up everything I've been reading here over time. It's hard to argue with, but I'll give you one:
DIY (as you call it) poly is indeed universally available. Any hardware store will carry somebody's version of it, as will any building supply outfit. Finding anyone's varnish, at least around here, is an excercise in futility, Watco excluded. And that as we all should know by now, is an oil mix.
If I want to use Waterlox, McCloskey's, Pratt and Lambert's, Behlen's Rock Hard et al, I have to order it in.....this can be a PIA. Convenience frequently is an advantage. Whether or not it is the deciding factor is situational.
Sure, if you are doing a quick and dirty project for the shop or around the house it makes little difference, but when you make furniture and have spent a considerable amount of time with joining and shaping I just don't believe it's a good thing to run down to the nearest borg to find some second grade product to slap on. There are all kinds of things that we now order routinely.
If you are not getting any result on cherry, I find that unusual. Maybe you have burnished your surface so the oil isn't getting into the wood.
As for dissing poly, Steve has covered it very well. Poly, in my opinion, has the look of "sitting ON the wood" rather than being "in" the wood. I am primarily a refinisher, and I can spot a poly finish from 20 feet. There are places for poly--like my floor. When there is such a better finishing varnish available, it seems best to use it, and for me, that is a non-poly varnish.Gretchen
I don't think I'm burnishing - I'm certainly trying not to. I usually sand to 220, changing paper frequently (I remember someone saying here "sand like someone else is buying your sandpaper" and in my case, this happens to be so...). I'm still on the fence vis a vis the "how fine does one need to sand before finishing" discussions.
If I'm not mistaken (thought I was once, but I was wrong), any varnish only finish of a certain thickness will sit on the wood - it takes the penetrating properties of oil to get that in the wood look. If one looks at it objectively, any application of an oil/varnish mix after the initial one has dried has to be superflous, because the initial application will have sealed the wood against further oil penetration. Thus only the varnish portion of such a mix is in play at this point, and one might as well be using varnish only, yes? Similarly, after an initial coat of varnish only, all other coats must sit on top, and it is the thickness of build that determines the on top/in the wood perception. That brings into play the clarity/haziness property differences of poly vs varnish, which would contribute to the forementioned visual perception.
So is much of this arguement really a matter of film thickness?
I cannot speak for your "eye" and what you see and/or want in a finish. Your explanation of all "varnish" all sitting on top of the wood is a bit esoteric for me. I will put it a different way--poly looks like a coat of plastic to me in a way that non-poly varnish does not--"sitting ON the wood" and not "in" the wood. You may certainly make your own choices.
Gretchen
The advantage is that you get a moderately protective "in the wood" finish that is essentially invisible. It provides more protection against spills and the like than plain oil, but it doesn't make the wood look like it has a finish on it.
-Steve
As opposed to oil followed by a thin topcoat after the oil has dried? Would there be a difference in appearance between the two techniques?
A single, thin coat of varnish would probably be pretty much indistinguishable, but a thicker coat, or multiple coats, will certainly have more of an "on the wood" rather than "in the wood" look.
-Steve
It is pretty funny to see all of the armchair chemists spar (pun intended) over issues like this.
To all,
I bet that the industrial suppliers are not really doing the things they do just for the sake of marketing. That's pretty naive. The VOC regulations have a lot to do with it. Twenty or so years ago, there were some really fantastic varnishes and other finishes available that can no longer be sold, and not because of marketing.
By the way, if a manufacturer like General Finishes or Minwax just thinned varnish with mineral spirits, it would exceed the maximum VOC level. You are doing the same by adding it to your polyurethane, which is not fair to the rest of us that live on this earth. The regulations are for the good of us all.
"It's time to change your evil ways, baby..."
You should contact Minwax and have them send you the finish you need. It can be delivered right to your door. Or better yet, try a shellac sealer, lightly sanded and topcoated with a water-based topcoat. Beautiful! Easy! Nice.
Hal
RiverCity Woodworks
http://www.rivercitywoodworks.com
Minwax doesn't make any products that I would want to use--their entire product line appears marketing driven. Since their Wipe-on Poly varnish is 70% mineral spirits, according to the MSDS, it's pretty easy to infer that they have added mineral spirits to higher solids content varnish.
So how does that not violate VOC rules. Except in California, the strict VOC restrictions apply only to finishes sold in containers larger than one liter. Varnish, and especially wiping varnish, is almost entirely an amateur product, so that likely would have a very little impact on sales of those products.
The total VOCs from all the DIY shops in the country would just be a drop in the bucket, so I'll thin as needed. Oil based varnish is by far the most durable finishing material available without needing special equipment to deal with hazardous and/or explosive fumes. I'll stick with oil based varnish for quite a while if I can.
Shouldn't we all try to use less VOCs?
Isn't continued use despite the health risks something similar to the folks that continued to smoke despite the warnings?
If I am not mistaken while watching a remodeling show that was shot in California I seem to recall seeing a bunch of small Minwax stain cans sitting on the floor waiting to be used. When someone asked about this they were told that CA would not allow the larger cans to be sold because of the VOC's, but you could buy the same amount in small cans. I really don't see the logic in this.
Edited 5/30/2008 9:08 am ET by GW52
>> but you could buy the same amount in small cans. I really don't see the logic in this. Perfectly logical from both the state's point of view and from the manufacturers point of view. The state is trying to legislate against the larger commercial use of high VOC materials. Commercial finishers will not want to contend with the higher price for small cans or deal with lots of small cans. They will opt for finishes that comply with VOC regulations. Small users, (ie: DYI) will still be able to get the product. As stated elsewhere, the commercial user is the primary user of finishes. The amount used by the weekend warrior of small finisher is a drop in the bucket (pardon the pun).Howie.........
It actually does make sense, in a roundabout and imperfect way. It steers large-scale commercial users, who aren't likely to want to buy a significant quantity of finish in lots of little cans, away from the high-VOC products, while still allowing small-scale home users to continue to use them. Since the VOC regulations are in fact aimed at the large-scale users, this works as intended.
It's analogous to the regulations concerning the purchase of ammonium nitrate-based fertilizers. You can buy a small quantity without any problem, but buying large quantities (which could be used to build a bomb) is harder. The regulations don't make it impossible to build a bomb, they just make it more difficult.
-Steve
Read page 6 of the MSDS. To my eyes, it contains tung oil. I'm confused.
http://www.waterlox.com/Portals/images/default/MSDS%205284.pdfDenny
Keep in mind that an MSDS is required to list only "hazardous" components that are present in the formulation at 1% or more. Tung oil may not meet the criteria for hazardous under OSHA's definition. A company may elect to list non-hazardous components.
To expand on the other Steve's reply: Traditional varnishes are a combination of a resin and a drying oil, such as tung or linseed. But they're not just mixed together; they're chemically reacted. They also contain a solvent to modify the working properties (unthinned varnish is usually too thick and viscous to apply). If you add a lot of solvent, you get a wiping varnish.
When you add additional oil to a varnish, you get an oil/varnish mix. Watco and any number of other commercial finishes are made this way. You can also add various kinds of wax, too. But a common feature of oil/varnish mixes is that they're an "in the wood" finish that's too soft to form a surface film. They must be wiped off after allowing them to penetrate for several minutes.
Polyurethane varnish is made differently, and the curing process is also different; however, it behaves more or less like a traditional varnish. And there's even such a thing as "oil-modified polyurethane," in which a drying oil is chemically combined with the polyurethane. But if you just add oil to a polyurethane varnish, you still get an oil/varnish mix.
-Steve
Seems to me if IIRC a chemist from General Finishes or Minwax posted on this forum or another popular woodworking site a couple of years ago about the topic of wipe-on poly. The notion that wipe-on poly is simply thinned out polyurethane is only partially true. By thinning out any poly you are essentially reducing the solids to solvent ratio and thus making a less durable finish. The chemist went on to mention the many considerations that go into developing a wipe-on finish lubricity, drying time, solids content, shelf life, etc.
>> By thinning out any poly you are essentially reducing the solids to solvent ratio and thus making a less durable finish.Of course, which is the reason that more coats of a thinned wiping varnish are required. At the 50/50 ratio, at least twice as many coats are required to get the same film thickness as a full strength brushed on coat.Howie.........
Yes, I'm sure the manufacturers have other considerations. Most are related to marketing . For example, if I mix my own varnish with naptha I may have a faster drying time than the broad market may want if I need more time there are other choices. The shelf life of the roll-your-own may well be less but since I would mix only what I need that is irrelevant since it only needs a shelf life a a week or two.
Naturally solids content declines, perhaps from about 50% for the "full strength" varnish (a few have more solids, and some less) to 33% using the equal parts varnish and mineral spirits ratio usually recommended. When you mix your own you can tinker--less thinner means fewer coats are needed.
General Finishes Arm R Seal tells us their gloss product is about 36% solids, Minwax doesn't say directly, but we can infer from the MSDS that the wipe on poly has about 30% solids. Solvent evaporates rather quickly, and the polymerization that cures the varnish film after the solvent evaporates is likely to be essentially the same with the wipe on and the brush on. That gives a finish that for a given dry film thickness is just as protective as the brushed on varnish. But it does take about three wiped on coats to build the same thickness as one brushed on coat.
Edited 5/30/2008 6:06 am ET by SteveSchoene
That's definitely true of waterborne finishes, less so of oil-based. Polyurethanes are a little different in the way that they work, and oil-based poly's do share some characteristics with waterborne finishes in that the chemistry of curing has to be "just right" to get the best results. Arbitrary thinning can affect the cure, but I haven't seen anything to suggest that the small amount of thinning that you would need to create a wiping varnish causes any significant problems.
-Steve
To summarize, to make a wiping varnish, use your favorite varnish or poly varnish and mix it 50/50 with mineral spirits. For a slightly faster drying, use naphtha.
You might want to try
50% Mineral Spirits
25% Satin Poly or Clear
25% Boiled Linseed Oil
Got this from an antiques dealer in New York an it works fine.
With these percentages, do you still wipe it off after application? The concensus in this thread seems to be that any percentage of oil requires that it be wiped off.
This is still 50% oil, and 50% varnish, exactly the same as the usual recommendation of equal parts of thinner, oil, and varnish. The thinner just evaporates--it's not involved in the finish in the end, do tinkering with the amount of it doesn't change things much at all.
I never had wiped it off, with the percentage of mineral spirits and poly it dries in about 8 hours.
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