When working with basic wood fixtures such as trim, cabinets, doors, and untreated furniture the process of finishing is the same. All wood surfaces to be finished need to be sanded smooth and completely absent of any paint, oils, or prior finishes. The wood needs to be bare and exposed. Although it is important to select the color of stain that you desire, consider that the type of wood also has a big influence in the color of the final finish. Different types of wood accept stain application differently resulting in lighter or darker color variations.
Wood that is sanded to a smooth clean surface will not absorb as much stain as rough, less sanded wood. Quality dense pine will take the stain in a solid even way while less refined wood may appear more blotchy with dark patches. Certain types of stain and colors are better suited for specific wood types.
There is not much difference between polyurethane versus varnish since polyurethane also has some of the advantages and disadvantages of varnish. Polyurethane is a modern product and is often considered a replacement for traditional old varnish. Polyurethane results in a hard and durable coat with a wider range of uses. The terms are often used interchangeably even though they are different products. Many older woodworkers may refer to polyurethane as "varnish" even though they are aware of the distinction. The process of applying polyurethane is simpler since polyurethane blends better with previous coats and is more forgiving in other ways. It is recommended that you use polyurethane.
Step 1: Sand and Prepare Wood Surface
Unfinished wood products from suppliers may have oils or other contaminants from handling on the surface of the wood. This all needs to be removed as it will negatively impact how the stain will be absorbed. Rough wood will not accept the stain as well in that although it may turn out darker, it will be blotchy and uneven. All wood surfaces need to be sanded down smooth and free of any oils or contaminants. An orbital sander is an excellent choice for aiding in the process. Take your time and sand the wood well.
For tips on sanding do your homework. In brief, sand with the grain of the wood. Select the appropriate sand paper that is intended for use on wood, and that is not too course. Rougher wood needs to be sanded with course paper then again with fine paper to produce the best smooth finish. After sanding be sure to remove all wood dust from the wood surfaces.
Step 2: Apply Stain in Coats
It is recommended that you avoid those "fast drying" stains. Use a modern oil stain product such as Minwax stain. I typically apply the stain with an old rag such as a sock, t-shirt, or cloth. If using an old cloth, make sure it is relatively clean and free of contaminants- don't use a dirty sock. There are special brushes for applying stain, however, I have had much better results using a cloth rag. In fact, have two rags available when you begin. One rag is for the application and a second rag is for removal of excess stain.
Apply the stain to the wood surface thoroughly saturating the wood. Do not use an excessive amount of stain. Do not allow puddles of stain to pool on the surface of the wood. You need to rub and work the stain into the wood. Do not be lazy and just slop on the stain. Dip a portion of your application rag into the stain container, then start to apply the stain to the wood, working it in going with the grain of the wood.
Step 3: Apply Polyurethane in Coats
Step 4: Smooth Finished Surface