Wood finishing doesn’t have to be complicated or mysterious. That’s not to say that even experienced finishers don’t run into problems from time to time; everybody does. But there are ways to make the outcome a lot more predictable and therefore less frustrating. Here are five ways to get good finishing results with the least amount of trouble.
1. Learn how to do three different types of finishes. Unless you build only one kind of project, you’ll need to know a couple different types of finishes so you can choose the appropriate finish for the project you’re working on. For example, a Shaker-style project will look fine with an easy-to-apply oil finish. But an oil finish would not look right on a more sophisticated project where a film-building finish like polyurethane, shellac, varnish or lacquer would be better suited.
These film-building finishes offer more protection but can have a steeper learning curve to use them successfully. For that reason, you should choose one of them and learn how to use it. It doesn’t matter whether you apply it with a brush or spray it on. Just choose one finish material and stick with it until you have it down.
2. Learn how to color wood, and which woods take stains or dyes well and which ones don’t. Many woods, even the finest ones, take stain or dye evenly and look better when colored, such as mahogany and walnut. No, you don’t want to bury the beauty of the grain or under a dark layer of stain, but color can often enhance grain and make the wood look warmer and more beautiful. There are many fine woods that don’t take color well at all, including cherry, maple and birch. And for my money, very open-pored plain-sliced red oak looks awful when stained. There are no softwoods that take stain well at all. All these woods blotch when color is applied and look terrible. Coloring wood is probably the most tricky part of finishing and the most artistic. It takes time to learn but is well worth the effort.
3. Know your finish before you start the project. Let the project style and the finish guide in choosing the right wood to use. Will it be stained? Will it be a simple oil finish or a film finish? How much protection does the wood need from moisture or scratches?
4. Make a sample, make a sample, make a sample. Unless you’re ragging on an oil finish, take the time to make a sample board from the same material as you are using in your project. When you make the sample, prepare the wood in the same way as you will for the project. Sand it with the same sandpaper grit progression and end with the same grit for the final sanding. Make notes if you need to. Apply color if your finish calls for it. Stain or dye a section of board, let it dry, then apply your topcoat leaving some of the board with just the stain. When it comes time to finish your project you’ll have a representative sample of each step of the process. And needless to say, if you don’t like the results on your sample, make another sample until get what you’re looking for.
5. Sand between coats. If your goal is smooth finish, learn to sand between coats to remove the small “nibs” that inevitably show up. These may be grain standing up after the first coat is applied, dust that falls into the wet finish or air bubbles that “pop” after the wet finish starts to dry and don’t lay out smooth. You can sand dry finishes with #240-grit stearated, self-lubricating aluminum oxide paper (usually grey colored). Or, wet sand your film finish starting with #400-grit wet/dry sandpaper. You can use water with a few drops of dish detergent for wet sanding. But wet or dry just be careful to not sand through the film, especially if you have stained the work.
We have many articles for free on the finer points of these finishing techniques right here on the Popular Woodworking website. Many are written by noted finishing expert Bob Flexner. We also have several great books by Bob in our online store including “Wood Finishing 101″ and “Flexner on Finishing.” You might also watch a full-length video I made on finishing: “The 10 Commandments of Finishing.” It shows you the techniques described above and more.