I’m finishing up some stain samples on oak. I finished them with two coats of Minwax poly, but am not happy with the results. I made the mistake of grabbing some scraps of window casing to make these with, so not having a flat surface they are making getting the finish even a difficult task.
I’d like to lightly sand and apply the final coat with a wipe-on technique rather than brushing, and apply just a thin coat. Can I thin the regular poly with turpentine or oil and do this? They make a wipe-on poly, but would rather not buy a new can just for this.
forestgirl — you can take the girl out of the forest, but you can’t take the forest out of the girl 😉
Replies
FG, I finished a curly maple pic frame using Wal Mart poly cut 50/50 with turpentine. Came out beautiful. I put it on with old flannel sheet scraps, let drya few hours scuffed with 00 steel and recoated 6 times. A soft deep finish that really brings out the waves in the maple. Have a great day and God Bless. Rick W.
ANY oil based varnish or poly varnish can be made into a wipe on finish by mixing it 50/50 with mineral spirits or naphtha. I like to use the naphtha because it will become tack free sooner allowing the application of the next coat.
There is no need to purchase a wiping varnish which will just cost more than making your own.
Thanks for the tip on using naptha as a thinner. I had never thought about this, but have seen it in a couple of places now. Sometimes I actually need to wait longer, but sometimes I'd like to re-coat right away. Love flexibility!!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Jamie, hope I'm not too late, but if I am, sorry I wasn't earlier... Dont try to thin regular poly. Just buy Wipe On Poly. I've tried everything and nothing compares to what comes out of the real can. And now, I'll vent a bit.. NAPTHA.... what, are you high.... Ha... I wanta see that work... Glob gluck gloop ... whoops was that my rag that just became part of the finish...
O.K. that was rough.. I'm done .... Sorry.. But seriously... try it on a test piece, you will be crackin up...Trust me... I just tried it.... LOL....Steve - in Northern California
Dont try to thin regular poly. Just buy Wipe On Poly.
And pay them full price for half strength varnish.Gretchen
I have been thinning both interior and exterior standard varnish and polyurethane varnish 50/50 with naphtha for probably six years and never had a problem. Just put two coats on a 30x42 maple tabletop yesterday and am on my way to do to more this PM. Naphtha has been used as an thinner for oil based products for many years where faster "flash off" was desired.
You will also find that all the book writing finishing experts recommend making your own wiping varnish and using either mineral spirits or naphtha. I have tried both Formby's Tung Oil Finish (really a thinned, wiping varnish) and Minwax Wiping Varnish and find absolutely no difference in them verses the homebrew. I'd rather make my own so I know what's in it. In addition, IMO, buying wiping varnish and paying MORE per quart than standard varnish is like paying extra to get watered down bourbon. Makes no sense to me.
Edited 6/9/2002 11:41:39 AM ET by Howie
Caution is in order when using Naptha as a thinner for poly. Naptha and shellac are not compatable! I recently found out the hard way. Having used a shellac based product (Seal Coat) as a sealer, I then used Naptha thinned poly as a top coat. The finished procuct would not dry! Ended up vigoriously scrubbing the sticky finih off with course steel wool and paint thinner. After drying used poly thinned with paint thinner and no more problems
The tabletop I am finish right now has a coat of Zinsser's standard orange shellac on it as the first coat. It now has four coats of wiped on standard varnish thinned 50/50 with naphtha. I have seen no problem and don't expect to. I have done this many times both with standard varnish and poly varnish. With the poly varnish I use dewaxed shellac.
The new Zinsser SealCoat is a dewaxed shellac and I plan to use it on my next project. I'll try to sample it in the next few days and then wipe it down with straight naphtha to see if there is a problem.
Howie,
Same experience here with dewaxed shellac that I've mixed. Now, what if he used regular shellac, after it had sat a bit and settled, and was using the high-wax stuff at the bottom? I would guess that the naphta would attack that stuff. On the other hand, that stuff wouldn't be suitable for any topcoat other than wax, anyway.
Gerry
I have been thinning both interior and exterior standard varnish and polyurethane varnish 50/50 with naphtha for probably six years and never had a problem
And I will add that I have been doing if for 40+ years. I don't use naphtha but have used turpentine and mineral spirits for my finish long before they even sold "wiping" varnishes. It's all in the marketing. Gretchen
Really, I won't argue with you but I would like to ask how you cut it. Do you use different cuts for different temperatures, etc.? My experience with naptha is that it tends to evaporate rather quickly.. Maybe I just have the wrong stuff. Perhaps you can enlighten me on the drying times between coats, etc.Expressions Fine Wood Working and Cabinetry..A division of Schefer Engineering Inc., Santa Rosa, Ca.
I would like to ask how you cut it. Do you use different cuts for different temperatures, etc.? My experience with naptha is that it tends to evaporate rather quickly.. Maybe I just have the wrong stuff. Perhaps you can enlighten me on the drying times between coats, etc.
If you will go back and read my post I stated I have not used naphtha--I have used turpentine (a long time ago) and mineral spirits. I cut it 50/50--I either brush it on with a foam brush and wipe off the excess or wipe it on with a rag. Depending on the humidity I can sometimes put 2 coats on per day. If you don't like naphtha or it doesn't work well for you then don't use it--seems pretty simple to me. You can make the choice.Gretchen
Rest easy, "Steve - in Northern California" (That's the signature I miss),
No, you're not too late. Actually, I ended up just settling for the finish I had, since these were just stain samples after all. I've seen the Naptha thing suggested in a couple of other places, but I'll certainly test before I try. Mostly, I'd only want to try it if I needed faster drying time for some reason.
Hope you're having a good weekend!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
"And now, I'll vent a bit.. NAPTHA.... what, are you high.... Ha... I wanta see that work... Glob gluck gloop ... whoops was that my rag that just became part of the finish..."
What are you talking about? I've been lurking around this forum for several months and have seen some ridiculous posts from you. You obviously have no idea what you are talking about. Why are you always responding to peoples questions like you have expertise as a wood craftsman? Now it seems you have changed your moniker from Steve Schefer to Cutoff and are starting a furniture making business! This is all quite scary to me. A few months ago on the old forum I recall you posting some of your beginning projects which were birdhouses for crying out loud. I also recall you poo pooing the need for jointing boards. These are just two of the examples of your inexperience that come to mind, there are many more.
I'm not belittling you for not knowing what you are talking about, I'm just saying that for the good of everyone that visits this forum with a question, you have simply got to stop trying to come off as expert and "answering" every question that comes up.
It doesn't look like you've read enough of Steve's posts to:
Understand his sense of humor
Appreciate the quality of work he has done
Know how much he has helped people with his answers
Know why he is having to establish another "handle"
Chill, dude, chill.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 6/9/2002 4:37:48 PM ET by forest_girl
Well... I must admit an imature response to an imature post would be most imature. So, that won't happen. You are entirely correct about everything you state. I am just a low life bum who makes bird houses and gives out bad advice. To make your statements really have effect, hit the ignore button and you will never see any of my posts again... Its your perogative... Please by all means, exercise it.
Oh, by the way, I do make furniture and cabinets and they are well accepted by my customers. If the fact that I am making money at doing what I love offends you, I am truly sorry for you.
Expressions Fine Wood Working and Cabinetry..A division of Schefer Engineering Inc., Santa Rosa, Ca.
Edited 6/10/2002 12:04:38 AM ET by Cuttoff
Personally, I like the mixture that Garret Hack wrote about a few year's ago in FWW. The 1/3 poly (or varnish) 1/3 boiled linseed oil and 1/3 turpentine (or mineral spirits). Just brush it on, let it soak in and wipe it off. Real simple and with enough coats, a beautiful and durables finish. I've tried the store bought wipe on polys, and while they're not bad, I like this blend much better. It really pops curly maple nicely. You have to be careful on oak, though, as it has a tendancy to bleed back out of the pores.
The finish you are describing is known as an oil/varnish finish. It's also the finish known as danish oil, antique oil and almost identical to most "tung oil finishes".
Rather than turpentine, most use mineral spirits.
Unlike a wiping varnish, the oil/varnish is a penetrating finish the leaves a close to the wood type of finish. However, it is very soft and not very durable. A wiping varnish is a true film finish that is varnish after the thinner evaporates. It has all the durability of a regular varnish as long as you build up a sufficient film thickness.
I'll agree with Howie, but add that it's relative. While a oil/varnish finish is softer than varnish, it's typically harder than tung oil, which is harder than linseed oil. Also, somebody mentioned a poly/oil blend, and that will typically rub out a bit different.
Finally, from this you can see that other than an equal oil/varnish/thinner blend can be used, and can even be varied between the coats. For instance, you can start with mostly oil, and end with mostly varnish. I'll note that even a small amount of oil will greatly reduce the hardness of a varnish finish, but it would still be harder than it would have been. However, you should start instead with targeting the gloss, smoothness, hardness, etc. that you want to achieve, then look for the method.
Gerry
I'm seeing a lot of reference to the use of Naptha. What is Naptha ?John
Naptha
Naphtha, term applied to several volatile, flammable liquids, obtained by distillation of various organic materials and used as a solvent for fats, gums, and resins, particularly in the manufacture of varnishes and waxes
Is this the Naptha everyone is talking about ?
View ImageNaphtha (Rectisol Naphtha BTX)Typical Analysis
Component
Wt %
Benzene
41
Toluene
16
Xylene
4
Oxygenates
7
Sulfur
1.1
Balance: compounds with unsaturated rings and aliphatic (no ring) compounds in the BTX boiling range.
John
Edited 6/10/2002 12:55:07 PM ET by John
John,
Naphtha is a term applied to several volatile, flammable liquids, obtained by distillation of various organic materials and used as a solvent. The most common petroleum solvents are mineral spirits, xylene, toluene, hexane, heptane, and naphthas. Aromatic-type solvents have the highest solvency for organic chemical materials, followed by naphthenes and paraffins.
For most common use, the solvent naphtha you can easily buy works (there's actually several grades, but you'll only see one) similar to mineral spirits, but evaporates much faster. For instance, if I want to wet a surface with a little solvent to see its "wet" look, I might use naphtha because it dries much faster.
However, an earlier post mentioned using naphtha instead of spirits so he could recoat sooner. Yes, it will dry (or set) faster, but the rest doesn't always follow. If it's an evaporative finish and naphtha is a true solvent, then he's right. But if it's something like poly than some of the primary solvent may still be present, and an early recoat will greatly extend the final cure time. If you did that and tried to rub out the surface some time later, you might not appreciate the results.
Gerry
Thanks Gerry, I wonder if there might be a problem with the finish fogging if brush on poly was thinned with Naptha. I'm thinking that the rapid surface drying that you mention would seal the uncurred finish below and result in oxidation from the slow cure occuring below the surface. I wish I knew more about finishing and mixing finishes, it appears that I could save a lot of money by not buying the pre-mixed stuff off the shelf.John
For a single coat of poly, there should be no problem. Even with slower drying mineral spirits as the solvent, the finish will set some time before it's cured. Depending on the type of poly, the coat thickness and temperature, it may take 8-24 hours for initial curing to complete. Unlike an oil finish, there's little oxidation in a reactive finish like poly. The can should give you an idea of the recoat time needed, and add to this if it's cool.
Note that "initial curing for recoat" is not the same as fully cured to be rubbed out, which takes much longer.
Bear in mind that the naptha will make it set faster, especially for a thin wipeon coat, so don't go back over any areas. (Actually, for a wipeon, I wouldn't use naptha.) Depending on the molding profile, another approach I've used is a foam brush, applying a thicker coat, somewhat between that of a wipeon and a bristle brush.
Gerry
I would not recommend using naphtha as a thinner for brush on varnish or poly varnish. To have varnish level properly-make brush marks disappear and bubbles pop--you probably don't want it to set up faster. Thinning varnish or poly varnish about 10% with mineral spirits will generally cause the varnish to flow and level better.
For wiping on however, the faster "flash off" is not a problem. You are wiping it on so fast and not going back over it, that there is no leveling problem. The faster flash off means you can recoat sooner.
If you want more info on coating products and their application, get Bob Flexner's "Understanding Wood Finishing". Every woodworker who does their own finishing should have it.
"For wiping on however, the faster "flash off" is not a problem. You are wiping it on so fast and not going back over it, that there is no leveling problem. The faster flash off means you can recoat sooner."
Howie, just quoted you so you'll know what portion of your note I'm referring to. I often wipe on large flat surfaces where I pour a big puddle in the middle of the piece then smooth it with a soft cotton rag. I have achieved excellent results with this method. Obviously this means that I am going back over areas that are already coated so I think the using Naptha would cause the problems that Steve (cuttoff) mentioned earlier.
Wow, is there a bunch to learn about this wood working stuff or what !
Thanks again for your help John
Probably not a problem. There is enough volume to the puddle that it is not going to begin to set for quite a will. As long as you keep in mind the waiter at Denny's wiping off your table, you will be fine. While naphtha does flash off faster than mineral spirits, you should not have a problem.
By going back over, I really mean after you think you are done then you see a spot you missed. The idea with wiping it on is that you are getting a pretty even but mostly smooth finish. If you go back four or five minutes later, then you risk messing up the finish. You should be most careful with the last two coats.
If you want a real fast flash off, use acetone. I've done this sometimes on small surfaces and always thin my varnish 50/50 with acetone when I spray it.
Finally, all you need to know about surface preparation, finishes and their pluses and minuses, how to apply them and then, most importantly, how to "finish the finish" can be gotten from Bob Flexner's "Understand Wood Finishing" and Jeff Jewett's "Great Wood Finishes". I recommend getting both. They are not really redundant.
Thanks Again Howie, I've heard of Jeff Jewitts book and will look for the other one. Definitely they will be a welcome addition to my growing library.John
Naphtha--more correctly VM&P naphtha, meaning Varnish Makers & Painters Naphtha--is a petroleum based solvent like mineral spirits. It is a slightly more volatile chemical meaning it is more flammable and faster evaporating. It used to be more commonly known as benzene. It is used for lighter fluid and camp stove fuel. Don't confuse it with bensine (note the "i") which is a carcinogen and is no longer available to the public.
Thanks Howie, for some reason I think I'll try to stay clear of it until I have a better grasp on mixing finishes up. Odd though, I have no problem using Laquer Thinner.. go figure.John
Hi TC, I've used a similar recipe (with Tung oil though) when restoring older pieces and really like it also. I've been looking at Watco for the current projects because I'm not up to making my own stains/dyes at this point, then putting a clear finish over it. Looks like there are many ideas from many people here!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
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