Vinegar and Steel Wool

Aged and distressed finishes are very popular today. Look in your average furniture store, and you’re not just going to find highly polished pieces, you’ll find a fair amount of distressed furniture mixed throughout. Obviously this isn’t all old furniture; it has been made to look old artificially. There are a number of special materials and special techniques which are used to do this.

Once upon a time, the only distressed furniture was made of barn wood. But there’s a finite supply of old barns to get the wood from and a lot of farmers who want to hold onto their barns. Since it takes too long to age wood naturally, woodworkers have had to be creative in coming up with ways to make their pieces look old, even though they are made with new materials. One such way is with a stain made from vinegar and steel wool.

Making Vinegar and Steel Wool Stain

Making the stain is simplicity itself, as it only has two ingredients. This is a very forgiving recipe, so there’s no reason to worry about getting it “just right.” Rather, just about anything done in making it will be good enough.

The recipe calls for using 0000 steel wool for this, the finest grade of steel wool that exists. It’s easy to find in the paint department of any home improvement center. One pad is usually enough. Some people tear it into chunks, but that’s not really necessary.

Place the pad of steel wool in a jar and cover it with common white vinegar. Stir the mixture and loosely cover it to keep dust out (as in just setting the jar lid on the jar, askew). Then allow it to sit for two to three days. The longer it sits, the darker it will get. During this time, the mixture will be outgassing, so it’s important that the lid is loose, allowing the gas to escape. If it is not loose, there’s a good chance that the pressure will break the jar.

Once the mixture has had time to react, the color will have changed considerably. It will be a dark amber or brown color. Stir the mixture and then fish out the larger chunks of the steel wool. At this time, the pad is likely to be broken up.

It’s a good idea to filter the mixture at this point, so as to remove the solid pieces of steel wool and keep them from getting into the surface grain of any projects. Pouring it through a paper towel or coffee filter is sufficient to accomplish this task, leaving the finished stain.

What’s Happening Here?

One of the things that vinegar is known for is its bitter flavor, which is caused by the acidic acid in it. It’s actually a rather weak acid, when compared to other acids like sulfuric acid or hydrochloric acid. Nevertheless, it is an acid and as such it immediately attacks the steel wool.

The first thing the acid has to do is remove the coating of the steel wool. As that is a mere patina of coating, intended to keep the steel from oxidizing (rusting), that’s not much of a problem. Once it gets through that, the acid attacks the steel directly, causing it to bond with oxygen and therefore oxidizing it. The coloration we see forming in the stain is actually caused by molecules of steel, bonded with an oxygen atom.

While we are using 0000 steel wool for making this stain, literally any steel could work. However, other pieces of steel, such as steel bar stock would break down much slower than the steel wool does. It is the large amount of surface area for the mass of steel, which makes this chemical reaction happen so fast.

Using the Stain

Applying the stain is much like applying stain to any project, with the exception that the excess is not wiped off. Vinegar and steel wool stain reacts with the wood, affecting the color. It does not react in the same way with all species of wood and plywood, so the end result can vary considerably. Oak, which is an open-grained wood, will tend to become rather dark, like espresso, while pine, which is a closed grain wood containing a lot of sap, will not absorb much stain, so it will not darken much. Generally speaking, the more open the grain is in the wood, the darker the finished color will be, as with most indoor stains. However, the coloration of this stain will vary considerably more than with other stains.

As with any stain, it’s a good idea to do a trial on a piece of the same wood that will be used in a project, before staining the actual project. This provides the opportunity to see how the stain will react with that wood, leaving an opportunity to adjust the stain, before use.

The finished vinegar and steel wool stain is actually rather strong, so it tends to provide a dark finish. However, this can be adjusted by diluting the stain with more vinegar. A ratio of roughly 1 part of the stain to 3 or 4 parts of white vinegar is good for many applications. This is the way to adjust the coloration of the stain, rather than by how quickly the stain is wiped off after application or applying additional coats.

To apply, brush on a good coating of the stain, enough to evenly wet the surface. Then allow the stain to dry in place. Do not wipe it off. The stain will begin reacting with the wood immediately, and continue reacting until it is dry. Same with plywood. This means that there is no real way of knowing what the color will be, until the stain is dry. The darkness and coloration can vary considerably, making it so that test pieces are very important.

Projects in which a vinegar and steel wool stain finish are used are normally varnished, after staining. This will affect the final color slightly. While polyurethane varnish is normally considered to be clear in color, it can cause the yellow in the wood’s coloration to come out more.

Unused stain can be kept and stored in a sealed jar. Before using vinegar and steel wool stain that has been stored for a while, be sure to mix or shake thoroughly so as to mix the rusted steel back into the vinegar and provide for a product with consistent properties.