One of the difficulties with learning to do French polishing is overcoming the exotic vocabulary that continues to be used by some: “charge the rubber,” “fad in,” “spirit off,” etc. This vocabulary was created by English craftsmen 200 years ago, brought to the United States, and used in most instructions since.
I’ve always thought it pretentious to use this vocabulary when there are perfectly good words everyone understands that can be substituted. Here’s the translation.
“Rubber” was the name given to what we commonly call a pad, made by tightly wrapping a smooth, finely woven outer cloth such as a handkerchief around a wad of cotton or wool cloth. The word rubber referred to the rubbing you do in French polishing.
“Charging” the rubber means simply adding shellac to it, as shown in the accompanying picture.
“Fadding in” refers to building up the finish as you rub more shellac onto the surface. So “building up” works quite well.
“Spiriting off” refers to using alcohol to remove the surface oil that was added in the building-up stage to make the pad glide more smoothly over the surface. A very small amount of denatured alcohol is added to a freshly made pad and rubbed over the surface. This is a critical step that is difficult to pull off because the alcohol can so easily streak the shellac.
It’s much easier to remove the oil with a product such as naphtha instead. Naphtha thoroughly removes the oil with a single wipe, doesn’t damage the shellac at all and evaporates within a minute or so. (They didn’t have naphtha 200 years ago.)
An additional term that is still often used is “linen.” You are instructed to use linen for the outer cloth. 200 years ago linen was the common fine cloth. Today we have finely woven cotton cloth, and linen can be hard to find. Both work well.
Water-based finishes have improved quite a bit over the past few years – to the point where they make an excellent finish for just about every woodworker. In particular, they offer a lot of advantages for DIYers and hobbyist woodworkers, especially those working in small shops. You can use a water-borne finish in place of just about any other film finish (varnish, polyurethane, lacquer) on just about any wood surface (furniture, cabinetry, trim work, and flooring). While it can be sprayed on, it’s likely that most DIYers and hobbyists will brush it on, which is what I do.
What is Water-Based?
If you’ve been woodworking for any length of time you’ve no doubt heard about water-based finishes, even if you haven’t tried them. Essentially, it’s any finish that uses water as a thinner and some kind of organic compound, such as glycol ether, as a solvent. If the product says to ‘clean up with water’ then it’s a water-based finish. Water-borne is just another name for water-based – though perhaps a more accurate moniker.
Water-based finishes also contain resins (along with some chemicals) that are dispersed in the water, so you’ll see these products variously labeled as water-based varnish or water-based polyurethane (containing a urethane or urethane/acrylic resin blend) or water-based lacquer (containing acrylic resin). The water and solvent evaporate, and the resin coalesces (merges) into a film on the surface of the wood, which is why they’re referred to as coalescing finishes. As with any other film finish they’re available in gloss, semi-gloss and matte sheens.
While there have been various problems associated with these finishes in the past, the new generation of water-based finishes are pretty darn good. Manufacturers are constantly improving both the quality of the resins they use, and their formulations (the secret recipes) for blending the various ingredients, to make the finishes easier to apply, tougher, more durable, and more resistant to scratching, heat, and solvents.
Advantages of Water-Based
There would be no reason to switch to a water-based finish if it didn’t offer some tangible advantages. The most important reason, in my mind, is that they offer a level of toughness and durability comparable to other film finishes. They are also a lot quicker drying so that less dust will settle and dry on the finish. You can usually re-coat your project within a couple of hours.
Water-based finishes are also the clearest finishes you can get, and they won’t yellow over time, as is common with oil-based finishes. However, some water-based finishes, such as General Finishes Enduro-Var) now have an amber cast that mimics the traditional oil-finished look.
They are also better for your health and the environment, and are safer to use. They have very low VOC (Volatile Organic Compound) levels, they’re non-toxic, non-polluting, virtually odour free, and they’re non-flammable.
Cleaning up after applying a water-based finish is a piece of cake. Water, a bit of soap, and you’re done.
Some Issues With Water-Based
A common complaint with water-based finishes is that they raise the grain – which shouldn’t be surprising given that there is water in the finish. While you could moisten the wood surface to raise the grain and then sand away nibs before applying the finish, it’s quicker to use the first coat of the finish as a sealer. It’s unlikely that anyone’s shop is so dust free as to preclude denibbing between applications of finish anyway. I use P320 or P400 paper between coats.
Water-based finishes are more finicky when it comes to temperature and humidity. They like to be applied when the temperature is between 70 and 80-degrees, and the humidity is no more than 70-degrees. If your shop is too cool, turn up the heat. You can even warm up the finish by putting the can in a bucket of warm water. If your shop is too warm or too humid, add a dry-time extender or distilled water to thin the finish. You’ll find this also helps when finishing a large project. Make certain you use an extender specifically designed to work with water-based finishes. The only one I’ve used is General Finishes Enduro Extender.
The characteristics that make water-based finishes exceptionally clear, which is often desirable on light coloured woods, is not so attractive on darker woods, which can tend to look drab. To enhance the grain you can stain or dye the wood before applying the finish, or add a dye directly to the finish.
Apply It With Brush
Because I now work in a fairly small shop I apply finishes with a brush. I’ve found that I get much better results on water-based finishes using a fine synthetic bristle brush with flagged bristles (Chinex or Taklon are good choices, along with Gramercy synthetic badger-hair brushes). I’ve not used foam brushes or applicator pads so can’t attest to their efficacy.
You’ll need to modify you’re technique a tad. Because these finishes don’t flow as well as other film finishes, and dry so quickly, you don’t want to go back over your work. Lay down a single coat, and then walk away. Don’t worry if you miss a spot – you’ll cover it on your next application. The finish will be dry in a couple of hours, enabling you to lay down a follow-up coat. Because of their high solids content water-based finishes build up quite fast – typically three or four coats is all it takes.
It’s a good idea to use your brush solely with water-based finishes, and to clean it thoroughly after each use. Work the bristles back and forth under warm water to remove the excess finish, and then add a little dish soap to the brush and work it through completely. End off by rinsing the bristles thoroughly, and wrap the brush in Kraft paper or Scott towels held in place with an elastic band. This allows the bristles to dry while maintaining their shape, and keeps shop dust from contaminating the bristles (and your finish).
Once a can has been opened, I always strain the finish through a paper paint strainer before I use it again. Any dried bits of finish that fall into the can won’t re-dissolve – they’ll just end up on your project.
Just like other film finishes you can rub out a water-based finish. It’s best to wait at least a couple of weeks, longer if you can. I use the same technique as when rubbing an oil-based finish, except that I use synthetic pads rather than steel wool and substitute mineral oil for mineral spirits. I’ve had better luck rubbing out water-based lacquer finishes than water-based polyurethane. Possibly because there’s more acrylic in the lacquer finish.
If you’ve not used a water-based finish before, or it’s been quite some time since you last used one, give it a try. I think you’ll be quite pleased with the results.
Unless you plan on using all the finish in the original container, you should pour the amount you expect to use into a separate container – for example, a clean jar or coffee can. It’s good to do this so you don’t introduce dust or other contaminants into the finish that you will use at some later date.
Especially with water-based finish, but a good idea with all finishes, you should strain the finish as you pour it. Convenient “paint” strainers like the one shown in the accompanying picture, are widely available from stores or online.
The reason straining is particularly wise with water-based finishes is that they are more likely than other finishes to contain solid particles of coagulated finish.
The rule for applying stain successfully is to apply a wet coat and wipe off the excess before the stain dries. There’s no problem doing this with common oil-based wiping stains. They dry very slowly, so there’s plenty of time to get the excess wiped off before the stain dries.
But water-based and lacquer stains dry rapidly, so it’s often difficult to get all the excess wiped off before the stain begins to set up. An example of the problems with water-based stain is shown in the accompanying picture.
Here are three ways to overcome the problem:
- If possible, divide the project into smaller sections and work on just one at a time.
- Wipe or spray the stain onto the wood, rather than brush it on, which is very slow, and work faster to get it all wiped off.
- Get a second person to help you. One applies, the other wipes off before the stain dries.
Water causes wood to swell, so most people think that wetting one side and not the other will cause the wetted side to bow – that is, increase in width so the center is higher than the edges.
If the wood is thin enough, this will be the case initially. But the overall swelling or shrinking after many wettings and dryings out, no matter the thickness of the wood, will be the opposite. The wetted side will shrink and the wood, or boards, will cup. The four accompanying pictures show examples of this. With a little thought, you will most likely come up with examples from your own experience.
The explanation is a phenomenon called “compression set” or “compression shrinkage.” When one side of wood is wetted the wood cells want to swell. If the thickness of the wood prevents them from doing this, they compress from cylinder shapes to oval shapes, and they don’t return fully to their cylinder shapes when the wood dries out.
The compressions are cumulative. So after many wettings and drying outs, the result is shrinkage. Eventually, the wood can’t shrink enough on the wetted side, so it splits. On a deck, for example, this shows up first as small “checks,” or splits all across each board.
None of this has anything to do with heartwood or sapwood up, or planesawn vs. quartersawn. The continuously wetted side will be the side that shrinks.
This is the reason wood exposed to water on one side should be protected with a finish in good shape and thick enough so water can’t get through. It’s the reason deck stains and water repellants are not very effective, and it’s the reason the message of the Antiques Roadshow, “Don’t Refinish,” has been so destructive to our furniture heritage.
Watermarks can happen in all finishes after they have aged and become somewhat porous. The marks appear light gray to white and are almost always very superficial – that is, right at the surface of the finish.
So one way to remove them that almost always works well is to abrade off the very top surface of the finish with fine steel wool or abrasive pad. Usually, the discoloration will be removed with very little effort, as shown in the two accompanying pictures.
The downside of removing watermarks in this manner is that you may change the sheen of the finish, making it flatter or glossier, and there’s no easy way to disguise this.
The first choice would be to blend the sheen of the rubbed area in with the sheen of the surrounding area. Do this by choosing a grit steel wool or abrasive pad that does this well. You can try several times with different grits to try to achieve a match. You can also use different pressures to “feather in” the rubbed sheen.
No matter how close you get however, a rubbed sheen never looks exactly the same as a sheen created by just the finish because a rubbed sheen is composed of scratches.
To get the entire surface, almost always a tabletop, uniform, you’ll need to rub the entire surface with the same grit abrasive. You could also apply another coat of finish on top. The least risky, if you don’t know the finish you’re working on, would be shellac, or wiping varnish padded on.
You might choose a finish for its durability, drying speed, ease of use or cost, but you might also choose for the color it imparts to the wood.
The accompanying picture shows unfinished oak at the top left, then seven common finishes and their color. If you haven’t done this comparison side by side, you may be surprised at the amount of difference.
On top row from the left: unfinished, clear paste wax, water-based finish and nitrocellulose lacquer.
On bottom row from the left: clear/blonde shellac, amber/orange shellac, polyurethane varnish and boiled linseed oil.
In practice, wax would be an unusual choice because it offers almost no moisture resistance. Linseed and other oils offer only a little more because they can’t be built to a moisture-resistant thickness. But they are easy to apply, so they work fairly well on objects without tabletops.
Of the remaining film-building finishes (they dry hard, so they can be built to several layers) water-based finish and amber/orange shellac are the most unique. Water-based finish imparts no color; it just darkens the wood a little. Amber/orange shellac imparts a lot of orange color.
You may choose either of these finishes just for the color.
It’s common to be instructed to apply a finish in the direction of the grain, called “with the grain.” Doing this is usually best when brushing a finish, but it’s rarely necessary when wiping or spraying a finish.
Brushing with the grain is best because the grain will help disguise the brush marks, the ridges and troughs caused by the movement of the bristles along or across the surface. If you brush across the grain, the brush marks will stand out in contrast to the grain of the wood.
There are exceptions, however. These include solid or veneer with their grain running in different directions – for example, breadboard, sunburst, parquetry, etc. If the grain of the boards or veneer runs in the same direction, it’s always best to brush with the grain.
Spraying, and wiping on and wiping off, are different. With spraying, as long as you build the finish enough so there aren’t dry streaks or areas with too little finish, it doesn’t make any difference in which direction you spray. For example, you might find it easier to spray horizontally on installed vertical panels rather than turn the air nozzle 90 degrees and spraying up and down.
With wiping, as long as you wipe off all the excess, it doesn’t matter in which direction you wipe on the stain or finish. The only consideration is in wiping off. If there is any chance that you may leave streaks, because you don’t get all the excess wiped off, you should wipe off with the grain.
There are risks to spraying any type of solvent lacquer over any existing, and older, paint or finish. The problem is the lacquer thinner in the lacquer. A wet application can cause many paints and finishes to wrinkle or blister, even an old coat of lacquer itself.
The two easiest ways to avoid problems are to spray several light (almost dust) coats of lacquer to get a bit of a build before applying wet coats, or to apply a coat of shellac before spraying the lacquer.
Both methods will create a barrier to keep the existing coating from being excessively wetted by the lacquer. But a fully wet coat of lacquer, especially if it has been retarded (lacquer retarder added to slow the drying), can still dissolve through and cause a problem. So observe closely what is happening.
Of course, brushing a brushing lacquer, which, by definition, has been retarded so it dries slowly enough to brush, is very risky and should probably not be tried.
Many people are confused about whether or not to refinish old furniture whose finish is in bad shape. They don’t really like living with the furniture, but they’ve heard (usually directly or indirectly from the Antiques Roadshow) that refinishing destroys value, and they surely don’t want to do that.
A finish serves two purposes. It protects the wood from contact with liquids, and it makes the wood look better, usually richer and deeper. The finish protects and decorates.
Clearly the finish in the accompanying picture does neither. In almost all cases it should be removed and replaced with a new finish that does both. It should be stripped and refinished.
Not doing so will probably mean the disappearance of the furniture. Well-built furniture outlasts people, the reason we have antique furniture. Though you, or whoever owns the furniture now, may be willing to live with the deteriorated finish, what happens to the furniture when it gets passed on? How many generations will treasure the deterioration, which will only become worse?
Not likely very many. This is the real shame of the message of the Antiques Roadshow, which typically runs as follows: This is a really unique piece of furniture. In its present refinished condition it’s worth about $5000. But had it not been refinished, it would be worth $60,000!
Groan. Why did someone refinish it?
Well, they refinished it because it needed to be, or it would have ceased to be useful. If they hadn’t refinished it, it probably would have disappeared into some landfill or fireplace and been worth nothing today. The current owner should be thankful someone cared enough to refinish the furniture, so they now have it to enjoy – or the $5000 if they choose to sell it.
There are exceptions, of course, but they are very rare. The appraisers on the Antiques Roadshow trade in these rare pieces, which probably accounts for their destructive message to the vast TV audience, very few of whom will ever come in contact with such rarity except in a museum.
The exceptions are usually very old, of very high quality, and were made by a craftsman who can be identified. Sometimes, an exception can be made for lower-quality furniture that was owned by an important historical figure, but you have to be wary of this sort of claim. I have had three separate pieces of furniture show up at my shop in Norman, Oklahoma that supposedly came from Paul Revere’s home, that little tiny house in Boston! He probably had only three pieces total, and all of them made it to Norman!
Of course, none of these three were anywhere near old enough to have been owned by Paul Revere.
Concerning value, unless the furniture is really unique, it will increase in value and survive with a beautiful, protective and decorative newly applied finish. It won’t lose value.