Wipe-On Polyurethane?

Re: Wipe-On Polyurethane?

Larry Clinton At Frankfort, (Central) Indiana

Mr Michael Dresdner used to be a frequent poster on this site (and some others). He has written books on finishing and in my opinion one of the top authorities on the subject. At one time the question you have asked was answered by him. As I remember (others may chime in), he said the wipe on formulations was exactly the same as the brush formulation except with more solvent added so it would flow properly.

He said you could purchase the regular formulation and add solvent for less money than purchasing the "wipe on version". The durability and other specifications will be the same as the normal version with the exception that the film thickness will obviously be thinner - additional coats will compensate so they should be applied per the directions on the container.

Re: Wipe-On Polyurethane?

Henry (Raleigh NC)

My RECOLLECTION from Michael Dresdner's (spelling?) book is this:

Wipe-on poly is a thinned out version of the full strength version. He recommends buying full strength stuff and thinning yourself if you want to use a wipe-on version. Again, as I recall, he recommended a thinned first coat (adding half, to as much as equal, amount of solvent to the full strength polyurethane) and maybe somewhat thinning subsequent coats (adding 5-10% more solvent).

I don't use this product much anymore (or any solvent borne finishes, except shellac) but recall that is what I have done with decent results.

A few other tips on practices you did not ask about - also from M Dresdner's writings:

He also recommended using a piece of 'non-woven abrasive' as an applicator - again something I have used with decent results (I used the white).

Lastly, on sheen. Traditional advice is to only use the satin or semigloss formulation on the final coat - building up layers of the satin or semigloss (with additional particles added to disperse light reflection) can make a finish look 'muddy'.

Henry

Re: Wipe-On Polyurethane?

David Weaver

i have only used the wipe on a couple of times, but I'll buck the trend with the recommendations and say that when you try it, if you do, just buy the can. If you find that you use it in volume later, then you can buy brush on poly and thin it if you'd like.

I found that, not surprisingly, it doesn't build quickly (poly doesn't in general, but it's thinned on top of that).

I also found the couple of times that I used it, if you're willing to wipe on several coats, it will look great assuming you did good surface prep.

I used a can of semi-gloss as far as I can remember. If you're going to build finish, as some have mentioned, the semi-gloss effect will build some through additional finish thickness, but unless you're going to build and rub out (that's territory for lacquer, not this stuff), good prior prep and building a thin coat of this only, until the aesthetic is good is the route I'd take.

Just don't panic if you wipe it on after three coats and it looks very uneven. All at once in the last coat or two, it will come together nicely.

Re: Wipe-On Polyurethane?

Dave Bair

I've always used regular thinned Minwax poly and wiped it on. The viscosity seems to change somewhat over the years, probably due to VOC regulations. The current (10/2019) batch is thin enough it can be wiped on without adding mineral spirits. Generally, a thinned down mixture requires more coats to get the same finish thickness as the unthinned version of the same product.

Re: Wipe-On Polyurethane?

Dick Coers

I agree with Dave. Straight from the can, regular fast dry Minwax poly will wipe on. BUT, if your intention is to wipe it on furniture you will likely need it a little thinner. When I wipe it on a big bowl, it starts to get just slightly sticky by the time I’m getting back to the start.

Re: Wipe-On Polyurethane?

John in Lutz

The wipe poly is easy to use but does not build a finish as quickly as I like. I do mostly turning and finish mostly with shellac. That will build a nice finish then I add one or two coats of the wipe on poly to provide a little more protection than the shellac give.

some information

Bill Tindall, E.Tn.

Someone in our club is a professional jewelry box maker who sells boxes for up to $500. He achieves as good a finish as I have ever seen on wood using Minwax wipe on polyurethane. He uses about 5 coats with sanding between the first two. He wipes on with a small piece of tee shirt material.

Another club member finishes his furniture with "wipe-on"....see slant top desk under Mayberry in Gallery. I think he brushes the finish.

Son in law is starting woodworking. He is using this same finish and getting results I would be proud of.

You didn't say what you were finishing. This detail could affect the advice. Like all finishing, it takes practice to achieve quality results.

How to make Wipe-On Polyurethane?

Bill Tindall, E.Tn.

I doubt the wipe-on varnish one buys is simply diluted full strength product for a number of reasons. I don't know if diluting full strength varnish will achieve the same properties as wipe-on Minwax, for example, but I doubt it. If someone experienced in finishing says the result is the same I'll stand corrected.

What properties must it have? The wipe-on viscosity needs to remain low for more time than regular varnish so the finish can be spread and leveled. After application one wants regular varnish to build viscosity quickly from solvent evaporation so sags and runs are avoided when brushing relatively thick coats of varnish. And, the product must pass EPA requirements. Companies get regular varnish to pass by increasing % solids, which increases viscosity. If regular varnish could be sold more dilute it likely would be so it would level easier when brushing. (I always dilute regular varnish now days, where in 1980 I didn't need to )

So, how would a company that understood the chemicals that go into making varnish go about making a varnish that had a long working time, where sags and runs were not a risk? A "long working time" means the viscosity of the varnish stays low for enough time to spread and level the material by "wiping" thin coats.

Viscosity depends on the % solids and the molecular weight of the resin component. Some claim that wipe-on is just diluted varnish. Indeed the initial viscosity of diluted varnish could be made low. But in a thin applied film the solvent will evaporate quickly and the viscosity will increase and make spreading and leveling difficult by wiping.

Oil could be added, the infamous 1:1:1 varnish, oil, solvent recipe. This material would wipe well as the added oil would dilute the resin and keep the viscosity low even after solvent evaporation. But the addition of the oil will result in a soft finish.

A smarter way to make wipe-on is to formulate with a lower molecular weight resin than regular varnish. Upon solvent evaporation the viscosity of the remaining film will remain low and it will still spread and level. The resin remaining after solvent evaporation will become hard and durable upon curing by air oxidation. My bet is that wipe-on varnish is made this way.

Re: How to make Wipe-On Polyurethane?

Larry Clinton At Frankfort, (Central) Indiana

Bill, I seriously respect your knowledge of chemicals, finishes etc. However the person I quoted is Michael Dresdner and is one of the most respected finish experts in the world. He still works as a (paid) consultant, but no longer gives out free answers to questions online. He has published books on the subject and has worked with producers of finishes. As to the VOC limits, I am not sure the limits are the same for the "wipe on coatings" as those imposed on the "spray coatings".

Michael Dresdner did state the properties and chemical composition of the "wipe on version" (I believe the question was regarding the Minwax poly) was the same as the normal Minwax poly with the exception of added thinner / solvent and did use the regular poly thinned for some of his projects.

Identical vs. Similar

David Weaver

I don't know the answer in this case, but could see it going either way.

I found an old MSDS for the fast drying poly that specifies the exact % of mineral spirits (58%) instead of the current range that's published.

And then one for the wipe on poly (69.7%).

There are some other low percentage hazardous materials listed, and then all of the non-hazardous are left out so that the "secret formula" isn't known.

I wouldn't be surprised if experimentation made a fast-drying wipe on that is similar to the wipe on product in a can, but not identical. Same as I wouldn't be surprised if some of the oils are modified so that the way the wipe on finish behaves is slightly different due to less assumed material on the surface of a piece to flow out.

I don't use either on a regular basis, and have no horse in the race, but sometimes when you're Dresdner, it's easier to say something that's very similar is "the same thing" than it is to explain in six bullet points what the exact answer may be.

solids content

David Weaver

for fast drying poly 550 - probably about 39% (which would agree with the 58% figure for mineral spirits plus a couple of percent of other hazardous items).

That would leave a guess of 100-69.7-3 or thereabouts for the wipe on type. 27.3%.

If one adds half of the volume in mineral spirits, the solids content of the homemade wipe on would be 39/150 = 26% (close to the guess of the wipe on type).

100% would give 39/200= 19.5%

In the scheme of woodworking, i'm kind of wondering what we're saving exactly. I understand the implications with a production shop, but I have to admit that if I still have my poly can, I haven't used the first quart. If I used poly, I'd probably use two or three quarts a year. I calculate a potential savings based on all of these assumptions of about 13% if buying the mineral spirits by the quart, and 23% if buying by the gallon. I know it'll shock some, but mineral spirits aren't something I keep on hand.

It does look like there's potential savings if performance is seemingly the same. It also looks like folks who thin it 1 to 1 and who think they're really saving are just working with fewer solids than the pre-mixed product.

Diluents

Mark Mandell - Gone Round In New Jersey

When I used oil poly I added 10% naptha as it thinned better and dried (not cured) faster than MS. Both MS and naptha are diluents (they dilute/thin the carrier oil) rather than actual solvents.

That's the other part of this...

David Weaver

If you really like the way the pre-mix works (I kind of liked it, I have to admit), from what I can tell even with something else (100% light mineral oil), not everything has the same feel, even at the same viscosity.

The flip side of it is that maybe I'd find a recipe that I liked better than the canned stuff, but I don't use it enough to tell for sure. The first thought with mineral spirits for me, though, was how do I know that the performance will be the same.

After that if you assume it may not be, does it really matter if it isn't? Probably not.

Side comment about frugality...

David Weaver

..not trying to pick a fight with the potential savings (for simplification purposes, here, it appears to be somewhere in the ball park of 10-25%, depending on brand. I was looking for minwax, but where I live, I guess home depot decided they couldn't get enough out of minwax and wanted to change the brand to watco so that they could get the extra $1 for a quart. I quite like most of what i've tried from minwax in the oil based realm).

At any rate, I would look at something like this and call it $3 on a project with $200-$400 worth of materials and write it off on whatever I liked to use better, or whatever is more convenient. That doesn't mean I think other people should uniformly agree with me - I've got plenty of other irrational things. Like I hate to spend money on consumables that "go away", like sandpaper. If I spend $10 in sandpaper on something, it's no big deal - but I rarely sand because the act of using the sandpaper and constantly getting bits and pieces out and throwing more away drives me up a wall.

It's gotten to the point that I can plane and scrape faster than I ever could, and i'm "not good at using sandpaper" these days.

comparison wipe vs regular

Bill Tindall, E.Tn.

The MSDS solvent data for wipe-on and fast drying are identical. The range quoted would allow the wipe-on to be simply a more dilute version of fast drying. Or, the % solids could be identical and the unidentified resin component could be substantially different as I suspect.

Trivial to determine % solids and I shall determine this value and report back.

Years ago, when EPA did not mandate lower VOC, varnish was about 35% solids and this product was too sticky to wipe.

I WAS WRONG about the prices..

David Weaver

Went to lowes today, and either i misread a listing or a listing (other than lowes) was wrong showing the pint price with a quart.

The wipe on at the local lowes here is indeed $13 a pint instead of per quart, and at that, I am back to it being worth making a wipable product, even if the performance isn't identical.

I calculate 3 pints of brush on around $15 thinned 50%, and at least with what I saw, solids would be in the ballpark.

I can't imagine that bill is wrong, that the wipe on is intended to set up differently, but I ended up leaving with a quart of fast drying poly instead.

I am not a finish worker (the kind of person who paints or wipes an area and keeps getting at it over and over - you know the type), I apply finish, let cure. If it sets up badly thick, then I apply finish thinly.

I learned this (and it sounds dumb or inane to even say this) when I started using S-W paints after a contractor did a room on my house. He said something along the lines of paint it and don't play with it. I had only used cheaper paints prior, and he left me with 14 windows' and a door's worth of trim to paint three coats on (one prime, two cover coats). It was a great learning opportunity for someone who knows little about finishing. Apply the finish, let it be what it will be, don't play with it.

My FIL likes to paint and is retired. He's painted a few rooms in my house when out here on vacation. It's nice to get the help, but he's a fiddler. He's notoriously stingy and is big on makework. It leads to less than stellar results with paint, as he'll go back and rework an area until he does it once or twice too late and leaves a few dull looking spots on the last coat. He prefers cheap paints (like behr at home depot) that don't cover that well and allow you to faff around for a while.

Re: I WAS WRONG about the prices..

Dave Bair

At Menard's, quarts of either wipe-on or brush-on are between $11-12.

Re: I WAS WRONG about the prices..

David Weaver

that's what I thought, too, but at lowes here they're not.

Maybe it's them and not me!!

At $13 a quart, i like the finish. At $13 a pint, it's over the line (to quote walter sobchak).

I live in the burbs. Not an "affluent" area, I'd say, but where the lowes is, I guess you could say maybe that it is. There have been plenty of times that I've changed my zip code on HD and lowes here to see the price go up 20% from the generic listing (things like pressure washers, etc). Never double like this, though.

I'll live.

Re: I WAS WRONG about the prices..

Terry Quiram

Amazon prime, WATCO wipe on poly $12.98 per qt. MinWax WOP $21.37 gloss, $24.21 satin both qt.

Use the regular Poly

Lee Schierer in McKean, PA

Two years ago I had some trim pieces that needed finishing. I don't recall exactly why I decided to do it, but I wiped the polyurethane onto the trim. I used the regular MinWax Fast Drying polyurethane. It worked great. I had stained the trim and applied three coats of poly, sanding between coats. The finish was smooth and run free.

Lee

Re: checking on menards, as mentioned..

David Weaver

..they come as far east as ohio, but I'm in PA.

$12.68 per quart.

Amazon is iffy on finishes. I'm surprised that watco is as cheap as it is on there.

I should've check the lowes website before driving there. It's $12.98 per pint on the website, just like the store.