Oils in general work to enhance the natural beauty and contrast of the wood. They go on easy and can be replenished over time as long as they aren't topped with some type of film finish, which is certainly an option. Nothing pops a figure quite like an oil, nor makes the wood really pretty. They are an easy alternative to stains, which are mostly just thinned paint.

If you use uninteresting wood in your projects, like pine or poplar, then you'd likely use stains (or dyes). But if you use really pretty hardwoods with awesome figure, then oils will be a big part of your gameplan.

Real tung oil (as opposed to tung oil finish) takes forever to dry, but doesn't yellow the wood quite like other oils and it is more water resistant. It is often used on metal to prevent rust.

 

I follow pretty much the same procedure for danish oil that I do for Tung oil. On soft woods it tends to blotch and it can also on hardwoods. I always wipe on then wipe off right away. Don't let it dry on because it leaves a sticky residue that you have to clean off. Just a wipe is all you need. Let it dry about 4 -12 hours depending on heat and humidity and repeat if needed.

Oils like all penetrating finishes will soak deeper into the soft grain, and you may need a pre-color conditioner to keep it from blotching those area's. I suggest a sample of whatever wood you are using as a test piece for finishes.

Oils bring out the natural beauty of the wood like no other product I've used.

 

Oil poly can be manipulated to produce any effect from an oiled look to a high gloss, so learn how to use it. It's a great finish.

 

Pure Tung oil is a drying oil, takes time to dry & cure. Matt or satin finish about all can expect, will develop a patina after several years of re-application. Pure Tung oil is easy to apply & repair. Same can be said of polymerized Tung Oil, about the same except dries faster.

Adding solvent to either pure or polymerized Tung oil increases penetration into wood and speeds up drying times.

Oil varnish blends contain oil, resin, and solvent. May or may not contain Tung oil, have to read label on can or check out material safety data sheet MSDS for list of ingredients.

Many oil varnish blends contain cheaper non-drying, semi drying oils, drying oils. Have seen products that contain real small amounts of both Linseed & Tung oils which seems silly because these oil dry differently, but does not matter because amounts so small.

http://apps.risd.edu/envirohealth_msds/MetcalfStore/WatcoDanishOilNatural.pdf

Wiping Varnish contains resin & solvent (varnish-poly). Usually no oil in a wiping varnish, so check ingredient list. Never want to buy a wiping varnish that is over 60% solvent.

Here is a Tung oil wiping varnish with 69% mineral spirits and no other ingredients listed.
http://hazard.com/msds/f2/ckc/ckctz.html

Another Tung oil wiping varnish product without any Tung oil
http://hazard.com/msds/f2/brx/brxhq.html

http://www.popularwoodworking.com/techniques/finishing/oil-finishes-their-history-and-use

When to use depends upon project and product selected, not sure any rules other than understanding end results.

 

As others have said tung oil can take a long time to dry a more modern oil base finish will give the same effect,dry faster and harder.

http://www.generalfinishes.com/sites/default/files/Tech-Data-GF-Arm-R-Seal-050311.pdf

 

It's pure myth that an oil will penetrate wood more if it's thinned with a solvent. The solvent may soak in a bit, but the oil won't go any deeper than if it weren't thinned, and that's only a few wood cells deep.

 

Tung oil (made from the tung nut) is interesting stuff. It is an oil, but upon exposure to air it becomes a wax over time. This is why it takes longer to "dry". One thing to know. When you store it, make sure there is very little air in the container or over time it will turn into wax. As I use it up I usually decant (pour) it into smaller and smaller containers, usually Ball jelly jars used for canning that are obtainable from the supermarket. I have also dropped some marbles into the jar to raise the oil level close to the top of the jar.

Planeman

 

Planeman…I don't know where you're getting your information, but pure tung oil polymerizes in the presence of oxygen, forming a relatively hard film. What do you mean by wax?

Heat and chemically processed tung oil like Waterlox, which is mixed with resins, solvents, and driers, will gel in the container, but pure tung oil won't.

 

Well…from my use it gelled up in the can like a wax from exposure to air, which, of course, contains free oxygen. I have never looked into the chemical content. The exterior of my finish buffs up to a warm luster after a couple of weeks after the application similar to wax. If tung oil has a "relatively hard film", is has never been apparent in my use.

My caveat is tung oil should be capped back up with as little air (oxygen) as possible or it will gel up.

Planeman

 

Oil in general offers little to no protection but looks great. Usually used in combination with wax on surfaces that will receive little wear and tear… e.g. cabinets; but not tabletops.

 

Not sure that I agree with that, Clint. To some extent, the solvent does work as a carrier, changing the viscosity of the oil. Thinner viscosities of anything will penetrate more deeply. This is why polymerized tung oil is mixed with a solvent, otherwise I'd be too viscous to do the job. But the question can be argued, "How much diluting is required to give more penetration?" IMO, this is the main reason that everybody has their own preference of ratios for oil-varnish blends.

But in porous woods, I think it's obvious that there is a proper mix that best works to get deeply into the wood.

 

Cosmic, don't you agree though that it's better to wipe it on and wipe it off as fast as possible. I mean it's going to penetrate no matter what you do but leaving it on just makes it gummy on top. I usually apply a couple coats and find that it's penetrated just fine without a buildup.

 

It depends, Russell. I like the process, so I'm likely inclined to put a few applications…never more than three. Other times, I'll just pour a bunch on, let it sit for an hour, then wipe it all off…wiping with mineral spirits to clean off any excess.

I'm convinced that the latter is more effective than the former when you want deeper penetration. I think we are too quick to wipe it off and we don't really let the oil work…and subsequent applications become blocked by earlier coats. Depends on the wood, of course, but I find this to be the case with oak and walnut, which get the bulk of it for me. Maple as well, but that's mostly on curly figured stuff.

Danish oil, which may or may not have varnish in it, would be applied in multiple coats.

 

BTW, my philosophy with oil is to make it look good. I'm not interested in complete saturation unless I think it will improve the looks. The exception would be something like a workbench where I'd want to protect it as much as possible from moisture (that doesn't have a film finish), or perhaps something that might stay outside, like a patio chair.

 

Cosmic, I'm working some padouk, red oak and black walnut today for a box. I decided to try some Danish oil cherry on the oak and walnut to kind of tie it in to the padouk. All I needed was a shop rag, blue paper towel and I just wiped a little on and it's done. Wiped it right off afterward.
I think with hardwoods you just don't get the penetration nor do you need it often times. They take on color pretty well from oils.

 

For oils, I tend to follow Bob Flexner's preferred method for application. Blotching should not really be a concern. You are not adding any dyes or changing the color of the wood, you are enhancing what is already there. Colored oils (like Walnut Danish oil for example) are a different story. I have never had any blotching with an oil finish.

1 - Prep the surface as usual. I generally sand through the grits until about 220 (sometimes 180 with really closed grain wood like maple)

2 - FLOOD the surface with the oil. I just pour it on. I am looking for a nice "slick" appearance. I will babysit it for about 30 minutes or so and touch up any dry spots so they are still wet (this could explain why I don't get blotching). I let that dry for as long as it takes - generally overnight.

3 - Once dry, I give it a nice light sanding with some 400 or 600 grit depending on the wood. then clean the dust off

4 - Rub on another coat. not flooding this time, but still babysitting the piece for about half an hour or so and touching up dry spots. After about 45 minutes to an hour, I'll rub off any excess that isn't going to dry.

5 - Let that sit for 10 days to 2 weeks then finish with some sort of varnish/lacquer/shellac.

In my experience, after the 2 coats of oil, that is all the wood will take. Any more than that and you are just asking for a gummy mess.

 

have 2 issues with "oils", the first is the time it takes to dry , if it does, I make a living doing woodwork and 2 weeks is not acceptable. Second, why, with the modern day oils and resins that dry fast, protect and hold up , why use the inferior ones, is it price, ease of application , I am curious, because I just don't get it .
I have personally tried all the good old combos, linseed oil, tung oil, my issue is , yes they look good initally , but 6 months, or a year down the road, not the case, I understand "renewing them", but my customers are not into reoiling and waxing furniture.
Not being a smart A** here, I just cant understand why folks would use inferior finishes, and they are , experience for me has proved it.

 

"To some extent, the solvent does work as a carrier, changing the viscosity of the oil. Thinner viscosities of anything will penetrate more deeply. "

Jay…. Simply not true. The oil disolves in the solvent just as sugar disolves in water, but neither the oil molecule nor the sugar molecule change. And the oil molecule, being quite big, won't go more than a few cells deep into the wood.

Pay heed to what Charles Neil just said.

 

Charles… There is a difference where you are making a living off wood (time is critical) and I am not. I wouldn't call oil an inferior finish. It suits a particular purpose, when specifically you don't want a film finish and you don't mind replenishing it. Heck, I think there might be a market for people with such furniture maintenance. I don't know…I always enjoyed the personal aspect of rubbing down an heirloom every now and then.

You mentioned modern day oils. Such oils, polymerized and/or with driers and/or resins shouldn't take two weeks to dry. Pure tung oil? Sure. But it still has some usefulness…just not in your line of work. Sorry, but just because things are modern doesn't always make them better…at least not philosophically. People have been trying I tell me for years that the NFL is better than MLB…sorry, but no.

Clint… Do you know how deep the pores of some woods run? Do you really think that oil, straight from the can, is at a viscosity thin enough to actually be at its smallest molecular level and provide all the penetration it can? When people pour coat after coat of oil into thirsty woods, where does it all go if not into the wood? You are a smart guy. You know the answers there.

I don't disagree with anything Charles said except that oil is an inferior finish. There might be better finishes for given applications, but such finishes don't become obsolete anymore than my Unisaw will once Gass has his say.

 

Btw, I use water-borne varnishes and modern lacquers. I understand the importance, speed, color-fastness, and protection of modern finishes. But I still like rubbing oil on a box. Nothing looks or feels as good.

 

Tung oil has significantly better water properties than BLO. I use tung oil on my canoe paddles, where an oil finish is much preferred over a film finish because it is much easier on the hands. It also does not yellow to the same degree, which is nice for maple paddles in particular.

 

Arguing how deep the oil penetrates is pointless as it provides next to zero protection and is strictly for appearance. Wipe on a thin coat and wipe it off, done. It's like arguing which canoe is better in the Atlantic ocean during a hurricane.

 

You guys know that tung oil provides some water resistance, right? The more protection you want, the deeper it needs to go. It does cure in the cells, polymerizing in the wood with exposure to oxygen, so it becomes something different once it's in the wood through is cross-linking. The more cells affected, the more surface area is covered and the greater this protection will be. It's not great protection, but its better than nothing…and if replenished often, it keeps working.

Even if no protection, then it penetrates and brings out contrast and figure in the wood. The more it penetrates, the deeper and more beautiful it will be. This is why people spend time putting on lots of coats looking for maximum saturation. This isn't an urban myth. It does make a difference in the look of the wood. If you don't believe it, then test it yourself. Don't take our word for it. It's not hard to put differing levels of oil on figured wood and experiment. I have.

No, it does nothing to protect against abrasions and dents. But neither do film finishes on things like workbenches. Oil is better in that application because it is easy to repair, IMO.

Oil has its uses, whether on wood, baseball gloves, workbenches, boxes, or boat oars. It has a look and feel unlike any other finish. Wood is an much of a tactile thing as it is a visual thing. Oil and wax finishes cannot be replaced in that regard. I wanna touch wood on many objects…not plastic.

There is a reason that guys like Jewitt and Flexner dedicate chapters to oil finishing. They understand the value and realize that there are other aesthetics to wood finishing that go beyond our eyes. And I wouldn't buy any finishing book that fails to talk about those qualities.

 

Clint. Why not cite your sources with regard to the inability of oils to penetrate? That's contrary to most of what everybody believes, especially seeing as how many people actually categorize oils as a "penetrating finish."

BTW, Jewitt advocates heating up pure oils to 150 degrees F to facilitate faster penetration when applying them. It's a viscosity thing, much like the way oil becomes less viscous in a car engine. I live in Texas, that's almost not necessary for me.

 

Jewitt advocates heating up pure oils to 150 degrees F to facilitate faster penetration when applying them

That sort of goes against the grain, no pun intended, more hazardous fumes, and more pentration?