How to Stain Floors
This is mainly pointed toward staining before finishing with Pure Tung Oil but will work for other finishes as well. The most common stain people reach for are products like Minwax oil base stain and other over the counter oil stains. The problems with these types of stains are two fold. They usually contain alkyd resin as the binder and pigments. (A binder is what holds all the ingredients together; alkyd resin is a type of varnish.) Alkyd resin seals the wood like a thinned down finish allowing less and less stain to be absorbed with successive coats. It also stops finishes from penetrating and binding well with the wood.
The pigments are the sludge that is on the bottom of the can that when mixed into the stain makes it muddy. Pigments are solid particles that do not dissolve. When applied in any thickness they act like paint obscuring the grain of the wood. These stains are not all bad; they just need to be used in their proper place. Minwax also now has a water base stain. According to their web site it is not to be used for floors. My objective when finishing wood is not to mask the natural beauty of the wood but also to add some color to enhance that beauty or to make it blend into the surroundings. Now what stains to choose? Aniline dye stains! Aniline is derived from coal tar. Don’t let that make you shy away from these types of stains. Anilines are very effective and light fast (fade resistance). Stains from things such as berries, tea, and coffee tend not to be as light fast.
There are basically three types of solvents which anilines are dissolved. Water, alcohol and oils. Anilines are available in hundreds of colors and can be inter-mixed to make custom shades. They come in dry crystal form and are then mixed with solvent to the dilution you desire. You can make a real dark stain concentration or make a light one by thinning. You can also build colors on top on one another. For example, if something is too red, you can add some green to make it browner.
The two easiest to work with in a large application such as a floor would be water and oil soluble.
Water will raise the grain of wood (make little fibers stand up). Before water staining a floor I recommend wetting the floor with water first allowing the grain to raise then sanding with the grain when dry. You may need to do this twice. Once the grain has been raised and sanded it will not keep coming up. You would then mix up the water soluble aniline dye concentration and stain the floor.
Stain boards lengthwise one end to the other from one side of the room to the other. Only stop at a seam between the boards. You may get a lap mark if you allow the stain to dry in the middle of a board. You can use a brush, roller, sponge or sponge mop for application. (Wrap sponge mop with nylon stocking to stop it from breaking up). Once you have the color you want proceed to finishing. Don’t worry if the grain is still raised in a couple of spots. You can go cut those rough areas off with sandpaper after the first or second coat of finish.
Oil stains are soluble in oil base solvents such as mineral spirits (paint thinner) turpentine, naphtha and also our Citrus Solvent. Mix the oil soluble aniline dye crystals to the proper dilution with solvent. Once you have the color you like proceed to staining the floor working the boards lengthwise with the grain from one side of the room to another. You can use a brush roller, sponge or sponge mop. With oil solvents the room must be properly ventilated. Usually a box fan blowing out a window will draw enough air out. The advantage of the oil soluble stains is that they do not raise the grain. Also Citrus Solvent and mineral spirits tend to dry slower providing more time to work the stain. When dry proceed with finishing.
Mixing Stain and Pure Tung Oil
You can also mix oil soluble aniline dye crystals with the Pure Tung Oil. First mix the crystals to a very concentrated solution of solvent (mineral spirits, Citrus Solvent) and crystals. Be sure all the crystals are dissolved into the solvent. When they are dissolved add to the Pure Tung Oil. This will make the oil tinted. You will not be able to get the finish as dark as if you stained the wood itself but this can add some color if you just want a little color.
Anilines dissolved in alcohol are just too fast drying for large applications such as floors. There can also be lapping problems because of the speed at which the solvent evaporates.
The above methods will provide a clear transparent finish for your floor. The results you see will be dramatic if you have only used over the counter stains in the past.
Anilines are available from: