Some types of wood, like pine, cherry, birch and maple, are notoriously difficult to stain. A board that has a nice, attractive grain pattern can end up with dark, splotchy areas after you apply the stain. But there's a simple way you can prevent most stain blotches. In this article, we'll show you how.
Dark splotches show up when stain pigments become lodged in areas of grain that are more open. Unfortunately, it's not easy to tell which boards this will affect. One test is to wipe your board with mineral spirits. Spots that are prone to blotching show up darker. But the best test is to apply stain to a sample of the wood you're using. If the stain appears uneven or has unsightly dark areas, run the additional tests we show here to determine the best staining process.
Most stain manufacturers make prestain conditioners, but you'll get better results with the method we show here. We're using a wipe-on oil finish as the sealer. The key is to apply a thin base coat to partially seal the wood before staining. Sanding sealers, dewaxed shellac and wipe-on finishes will all do the trick.
Some types of stain perform better than others on blotch-prone wood. In general, gel or heavy-bodied stains work best. Since these types of stain tend to have a high concentration of pigments, they also work better if you have to add several layers for a darker color. Just make sure the sealer and stain you're using are compatible. Using products from the same manufacturer is the safest bet.
Photo 1 shows how to make a test board with different concentrations of sealer. The concept is simple. The percentage of solids in the sealer determines how completely the pores in the wood are sealed. If the wood was sealed completely, it would be difficult to get any stain to stick. Diluting the sealer with mineral spirits allows you to experiment with different degrees of sealing. When you apply the stain (Photo 2), you'll see the results. Then you can choose the dilution rate that delivers the best results for your project.
Let the sealer dry for a few hours. Then sand the wood lightly with 220-grit paper before applying stain.
An inexpensive turkey baster is a great tool for measuring small amounts of finish and mineral spirits. Mark the baster with a permanent marker. Just draw out equal amounts of sealer and solvent to make a 50 percent solution. We used disposable plastic cups as mixing containers.
End grain can look great and complement the board's surface, but it often ends up too dark. The solution is simple, though. Use the same prestain sealing method we show here to seal the end grain. You can also use this method on woods like oak that don't require a prestain sealer. Just be careful to sand off any sealer that gets on the face of the board before you stain.
Start by making a test board with your chosen sealer concentration. Then stain the entire board. Let it dry and add a second layer of stain to all but one section. Repeat this process until you get to the desired color depth.
However, applying multiple coats of stain isn't always the best way to achieve a deeper color. For one thing, it'll take a long time to finish the project. You have to wait for each layer of stain to completely dry before adding the next. Otherwise, the new coat will dissolve the previous coat and you'll have a real mess on your hands. In fact, some stains will dissolve the stain below even if it is dry. (That's why testing is critical for a nice finish.) Another problem with multiple coats is that the stain will begin to obscure the natural grain. One solution is to opt for a less concentrated sealer. You'll get a bit more blotchy appearance, but the grain will show up better—a fair compromise.
Treating your test board just like the finished project will give you a true representation of the final color and depth of the finish. Make sure you sand the test board with the same grit as you intend to use on your project. After you arrive at the desired degree of sealing and number of stain coats, apply the final clear finish to see how it looks. This is also a good time to test the effect of different sheens. Most finishes are available in sheens ranging from almost flat to high gloss. You'll be surprised at how much richer the stain looks after a coat of finish.
Seal Pine Before Staining
Dark stains on pine can look horrible. In addition to blotchiness, the softer areas between the grain lines soak up stain like a sponge, creating an unnatural look. The photo below shows the dramatic difference between the raw and sealed areas of pine using the same stain color. Experiment with sealing the wood on your next pine project. You'll be amazed at the results.