I'm going to continue the procedure I started in the sanding article. I will talk about what type of stains to use on particular woods, and the best methods to apply them. I will also talk about the dreaded white pigmented stain, dye stains, and ebonizing wood floors. I hope you find the article enjoyable and informative.
Well, I hope for your sake, the sanding has gone well, and you have checked for edger and "drum chatter" marks. So now is the time for a really thorough vacuuming. You must get the dust out of the wood grain, especially on ring porous woods like oak. Use a powerful industrial vacuum, even if you have to rent one. Go over the whole floor at least twice, and don't forget the corners and edges should be done with a crevice attachment.
The stain should be one that is suitable to the species of your wood floor and one that applies easily to a large wood floor surface. There are 4 basic types of stains. The pigmented wiping stains are the most prevalent. They contain a small amount of pigment, which is carried along by the large amount of solvent in these stains. The pigment particles are fairly large, and lodge in the pores of the wood. Oak, ash and hickory do well by this sort of stain. There is a binder in this type of stain, that is a diluted form of varnish. When the stain is dry the binder will keep the pigment particles (being dust-like if they dried on their own) from being wiped from the pores.
Use a rag to apply this stain, as you will be flooding the surface with the stain and then working the stain into the pores of the wood and any cracks. Only rags seem to do this well. Try to use the most lint free cotton rags you can find. This may seem fussy, but will save you from having to sand lint out of the dried floor finish later.
This type of pigmented stain is applied in long strips with the run of the floorboards just as wide as you can comfortably reach. Even parquet is done this way, but dont necessarily choose the long side of the room. In the case of parquetry try to start your first row of staining so that it points toward a large window. This will avoid a checkered appearance in the stain.
Wipe within a few minutes, and work very fast or with a partner if it is a long room. Be sure to rub the stain into the wood thoroughly. If you have missed any spots with a pigmented stain, and it dries, touchups are tricky. The solvent in the stain will tend to remove the pigment particles when you try to touch up a small area. You have to very deftly wipe the stain on and off the missed spot. So please try to do it correctly and evenly the first time. Your floor is not the place to experiment. Do some samples first to get used to the process.
The trick with this stain is to wipe vigorously enough to even the color out, but not too much or the wet pigment particles will be wiped out too. The darker the color the more difficult this stain is to use. Some of the darker stains like the Dura Seal brand contain a lot of pigment, but a lot of binder. This will make it easier to achieve the darker richer colors, but you must wait 24-72 hours for this type of stain to fully dry. If the stain binder is not fully dry it may then interfere with the polyurethane that you apply on top of it. You may end up with a bubbled finish over the stain or at worst a peeling finish. In the case of peeling, you will have to sand the floor all over again. This is no place to be trying out a new stain brand, practice on a group of hardwood boards held together by a clamp.
Test the adhesion of any stain and finish combination by letting the finish cure (on a sample) for 2-4 weeks, then cross hatch it with a razor knife to the bare wood. Apply a strip of duct tape and rip it off. If more than 20% of the finish peels find another product or method. I describe the locally made stain I use in my article on the use of oil modified polyurethane. This is a "fast dry" pigmented wiping stain, and it always dries over night, but is tricky to use. And may be hard to obtain. So see if you can find one made locally yourself. A company that supplies stains and finishes to your local furniture trade is the best source. It may be worthwhile asking a furniture maker or refinisher in your area for this source.
The next type of stain that is best used on non porous wood is the dye stain. If you have a maple, birch, or beech floor for example you will find the pigment stain tends to make the wood blotchy. Dye stains are very similar to fabric dyes (and yes you can use Rit Dye stains to dye wood) in that they both contain particles that are so small that they enter the wood surface itself. But this doesnt make them easy to use on floors. It is much too easy to create overlap marks with a dye stain. Dye stains come in water soluble powders (which makes for a very grain risen floor) and NGR type stains already mixed. The NGR (non grain rising) wood stains contain alcohol or lacquer thinner solvents and are really dangerous to use on large floors. But it can be done.
One very important warning about dye stains, is that they are not very colorfast. Imagine laying a nice red sweater out on the floor for a few years exposed to direct sunlight. Well this is the same sort of dye used in woodwork. The NGR dye stains are even a bit less colorfast than the water soluble one, but both will fade remarkably in 5-10 years, when exposed to light. They will show rug marks like crazy in just a few years also. This together with the application difficulties makes them an unpopular floor stain. So keep dye stained floors protected from direct sunlight. The best way to do this is to use UV resistant polyurethane and at least 4 coats of this. This finish itself will tend to give the wood a yellow cast so be sure to do a sample using this finish on it before you commit yourself to a final color of the finished floor. Another important factor with water based dye stains is that water based finished applied to them will make the dye run. If you wish to use water based dye stain, use an oil-based poly, lacquer or shellac finish on top of it. But if you want to use water based finish for the topcoats, you must use a NGR or oil based dye stain to color the wood. Always test for compatibility, I cannot say this often enough.
In fact I always show my customers the stain applied directly to the sanded floor surface. I will do as many stain samples right out in the bright light as they wish to see. Ill sand them out later. But this gives the customer a chance to see the color in the evening and early morning lights. The early morning light may not be so flattering to some stain colors as you may think, so let your customer decide. Be sure to apply at least one thick coat of satin or gloss finish, on these sample patches, as this too will change the color a bit.
You can use a rag to sponge on a lot of this dye stain, and because it dries slowly you should have plenty of time to wipe, but this would be a good place for an assistant. Some wood workers sponge the wood with distilled water before they use the dye, but be aware of using too much water on a wood floor. I will talk about sponging before staining later in this article. Applying more coats of stain will intensify a dye stains color, so dont be too disappointed with the first coat of stain. But the key here is to mix a stronger color or even a different color for the next coat of dye. The color you see when a dye stain is wet is its true color. When these stains dry they seem to fade, but the true color will come back when you apply the floor finish. Wait at least 12 - 20 hours before you apply more stain coats or begin top coating. Provide lots of air circulation. This job is best done in the winter heating season. Warm dry air is best.
A bit of a compromise to these first two stain varieties is the dye -pigment combos. The Minwax wood stain finish is one of these. It is quite easy to use and is quite popular among floor finishers for this reason. But these dont come in very dark and rich colors. You may find that some of the lighter colors may be suitable for using on nonporous woods like maple.
The next type of stain is the gel stain. This is the best stain to use on softwoods like pine and hardwoods like cherry. These woods have such a variable density that they will turn quite muddy and blotchy if you try to use a pigment or dye stain. Gel stain is thick like ketchup, but once you wipe them they flow quite well on the wood surface. They penetrate the wood easily and evenly. And are easily wiped off to even out the color. They generally have long dry times and come in a variety of viscosity's. Minwax is the thinnest, Flecto is medium and Wood-Kote and Bartleys are the thickest. The thicker stains will generally color more intensively. Experiment with not only different colors but different brands. Cherry is good candidate for a gel stain, especially if you have installed a low grade of cherry with all those light colored boards. The gel stain will be the best type to even this out.
The last stain for floor use is the Ashphaltum type stain. Its also called a bitumen or glisonite stain, and is basically a heavy petroleum product. It stains the wood like a dye, but is easy to use like a pigment stain. And like a pigment stain is colorfast. Watco and Deft oil are two such products. But be aware they have long dry times also, and because of the oil base, not be compatible with some finishes. But this sort of stain can also be successfully and easily used on maple, birch and beech, but only in the lightest colors.
Lots of people ask me about white stains, and complain that they have trouble getting the white color to take into a wood like oak. Well there is a secret to solving that dilemma. The sanding process has to have gone well, but in this case dont spend too much time polishing the wood with the buffer. You really dont want to make the floor so smooth that the pigment particles wont lodge. Just be sure to remove all the visible sanding marks.
I mix my white pigmented "fast dry" wiping stain with a little bit of gray stain of the same brand. The ratio of white to gray depends on just what look you are trying to achieve. You can also mix these stains with a red mahogany color to achieve a pinkish wash to the floor, or even a universal tint of blue or green. The added dark pigment (dont use too much) will make the stain easier to use, and the white wash color you were expecting will come though. If you wish to know the specific brand I use here in Toronto, Canada, e-mail me at firstname.lastname@example.org and I will try to find someone that will ship it to you. Otherwise try the Bona Kemi brand wood stains or the Dura Seal pastel white, these are what most pros try to use anyway. These brands are available nationally, so these are what are practical for me to mention in a web article.
Another more tricky way to white stain a hardwood floor is to sponge the wood with distilled water, and let it dry overnight. You will then find all the pores of the wood open and willing to accept even the lightest colored white stain. I used this method a few times in the past, but it is risky in a humid climate. A blue-black fungus may show up in red or white oak overnight, if the wood has dried too slowly. These are visible as little black dots all over the floor, and can only be removed with a fine sanding, defeating the whole sponging exercise. You should try this only in the winter when you can really dry the floor with the heating system. And ventilate after you sponge, so the wood dries fast. I dont use this method anymore, too risky.
You could also consider sanding the floor only to 60 or 80 grit. This will help the white stain pigments lodge in the wood better, but wont be as smooth. This may be fine if you dont mind seeing some sanding lines in a floor for a more rustic and textured finish.
Oh, and by the way, you must finish your white floor with a clear finish, else you will in time, have yellow toned floors. The clearest finishes on the market are the acid cured or Swedish finishes. Glitsa and Synteco are two of these. The problem with these is that they emit formaldehyde gas for up to 90 days after application. A bit safer are the catalyzed water based finishes. Bona Kemi and Basic Coatings are the major producers of these. The catalyst is very toxic to the skin and is a possible carcinogen, so handle this stuff carefully. And the last choice would be a clear lacquer nitrocellulose finish. But be sure to read all about this explosive finish in my Lacquer Floor Fires article in this site. The Swedish finishes are also about as flammable as the lacquer. Consider having a well-seasoned pro apply any of these flammable or poisonous clear coatings.
Lastly we get to the Ebonizing floor stain, which has been vexing wood workers and floor mechanics for years. Just how do you make a wood floor black in color? And I mean an even and deep tone of black, showing the wood grain and having the early and late wood (of a ring porous wood like oak or ash) come out with almost equal tones. Well its not easy and the bigger the floor the more difficult it will be to control wiping and dry times.
An easy solution for a new floor installation is to go with black pigment stained prefinished hardwood. Be sure to ask if it is pigmented stained, else the color will fade in time. Some prefinished floor makers have added UV inhibitors to the factory finish, Lauzon Ltd. is one of these brands. Visit their site at www.lauzonltd.com. This will give you the factory consistency that you may never be able to achieve on site. Find out first though if they have used a dye stain on these factory boards. And if the warranty covers fading of the dye stain color. I doubt it.
But if it is an older floor or if you object to the harsh light reflective qualities of prefinished floors, you must use a black dye stain for sure on all woods to create an even color. A water based black dye stain will do well on most woods, except oak. The pores of many ring porous woods wont be well stained with this kind of dye. So in this case you will have to go over the floor again (after the water based dye stain has had 12 - 20 hours of drying) with a black pigmented stain to color the pores evenly. Make sure that the pigment stain is a oil/varnish type so it doesnt wipe out the water based dye stain. Its a tricky operation to keep everything consistent on a large floor area. You may have to price a job like this on a time plus material basis, in order not to leak profits.
Here are some more hints to working with the water based dye stains. It will take about a 1/2 pound of dye power to make a gallon of wood stain. But you should mix the first batch twice as strong and then dilute it. Use distilled water for all these dyes. And weigh the amount you are using, and measure the water volume accurately. This is a must if you ever want to repeat the same color, keep good records. You can mix small amounts of dye stain using a drinking straw to hold a measured amount of water, and an accurate scale to weigh a small amount of stain. Once you have the right mix, scale up the amount and mix the usable batch.
If you can find a good NGR black stain you may be able to do the staining with one product. Be prepared to stain the wood with dye stains several times to achieve the blackness you want. But dont over do it or you will have a floor so black you might as well have painted it. Some NGR stains contain lots of alcohol or lacquer thinner, so they may be unsuited and dangerous for large areas. They tend to not be as clear as the water based dyes, and are less color fast in some cases.
I try to talk my customers out of these experimental colors. I cite the fact that my time is expensive, and results on a sample board may not be as easy or even possible to achieve given the mechanics of controlling a stain on a large floor area. The white stain floors will get shoe scuffed and dirty in just a few years.
I did a custom white stained oak floor for a customer, only to be called back in 4 years to resand the floor, and this time apply a dark walnut pigmented stain to the floor. In this case, the housekeeper (of 20 loyal years) was about to go on strike. She just could not ever wash this lily-white wood floor clean enough to her satisfaction. The very pores of the wood were darkened by dirt. I have also found that white-stained floors tend to show dark unsightly gaps in a few years. These pretty floors just dont age well.
Oh, and that reminds me, there is certainly an alternative to white staining a floor. Choose a really clear grade of hard maple and ferret out any dark pieces before installation. And instead of white staining it, apply the catalyzed water based finishes I mentioned above. This will give you the white but woody look you may like after all, without the mess and fuss of staining.
And do be careful with the dye stains, they will fade. Imagine what your floors will look like when exposed to too much light in a few years. But what the heck, its your floor have fun with it. As long as you have installed a 3/4" thick strip or plank floor, you have 6-8 resandings in the future. These fussy stains will keep us floor mechanics employed expensively for many years to come. What, me worry?