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Wednesday, January 7, 2004 Condition softwoods before staining By TIM CARTER Q. I have to stain some white pine woodwork in my home. In the past, I have had nothing but problems when I stain wood. The color is not even, the grain disappears and colors are much darker than in the sample brochures. I must be doing something wrong. How can I get professional results from start to finish when staining woodwork? — S.B., Westland, Mich. A. I see you have the softwood blues. I used to get into this same funk many years ago when I first started in the construction business. Imagine my customers’ reaction when I transformed beautiful white pine woodwork into a blotchy mess. My initial diagnosis was that the wood had not been sanded well enough. But I still had problems when the wood was as smooth as glass. I continued to ruin gorgeous pine trim because I did not understand that softwoods must be treated with the utmost care when they are stained. White pine, alder, spruce and fir are softwoods that have a very open cell structure. They readily absorb massive amounts of stain, much more than you and I want them to. Hardwoods such as oak, poplar, cherry and walnut are much different. Their dense cellular structure make them harder; because of this, there are simply fewer voids for the liquid stain to penetrate. A suitable comparison might be comparing two different pieces of paper. A paper towel readily absorbs water drops, while a drop of water may sit for minutes on the surface of glossy paper used in many decorative coffee tables books. When I decide to stain softwood lumber, I do what professional painters and woodworkers do and use a clear conditioner to partially block many of the wood pores. These conditioners are easy to apply and dry rapidly. Often you can brush them on the piece of wood and be able to stain within 15 minutes. The liquid conditioners contain clear resins and solids that clog the pores of the softwoods. By doing this, many of the stain pigment particles that create the actual color are not allowed to soak deeply into the wood. The conditioners also help to enhance the grain of the wood. Sanding is still extremely important when staining wood. Roughly sanded wood exposes more surface area, which allows too much stain to soak into the wood. When you take the time to use progressively finer and finer grit sandpaper to eventually produce a glass-like surface, you minimize the surface area of the lumber. Taking the time to fine-sand until the wood surface is super-smooth also is key to achieving a silky surface after the final coats of finish are applied. After you have sanded the wood and removed all dust, apply the clear conditioner. Pay attention to the instructions as they often state that any wood treated with the conditioner should be stained within two hours. Apply the stain and work it in well with a rag or brush. Wait perhaps 30 seconds and wipe off the excess stain. All too often people make a mistake by either rubbing too hard or using a rag that is saturated with stain. (It’s a good idea to practice first on some scraps of woodwork.) Keep in mind that the depth of color you see the moment the stain is wiped off is generally what the woodwork will look like after the clear finish is applied. Be sure the stain dries before you proceed. If you try to rush the job, the clear finish can lift stain from the wood, resulting in a blotchy mess. Your choices for clear finish coats are many. Lately, I have become a huge fan of water-based clear urethanes. They are easy to apply and dry rapidly. When I use these, it is not uncommon for me to apply two or even three coats of finish in the same day. That can be a huge timesaver. When working with any clear finish, be sure to check the work as you apply the finish. If you apply too much clear finish, it may sag or run in spots. After you apply the finish to a vertical surface, you have a window of opportunity of perhaps 5 minutes when you can correct these errors with your brush instead of waiting for the finish to dry and then sanding out the defects.
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