Difference between revisions of "Staining and Finishing Wood"

Revision as of 15:13, 9 January 2015

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. The quality of the wood is important. Consider that better quality pine will take the stain in a solid even way while less refined lower quality pine 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 which reside 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. Blow off surfaces with compressed air. Wipe the wood with a clean dry rag.

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.

• Use 2 clothes, one for application and one for excess stain removal

The can of stain really settles during storage. You should not shake the can. You need to open the can and stir it well with a stick. Make sure you scrape the bottom of the can while stirring because the stain solids really like to settle and stick to the bottom of the can.

• Stir can of stain well

Apply the stain to the wood surface thoroughly saturating the wood. Do not use an excessive amount of stain, but be sure to use enough. 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 and going with the grain of the wood. Apply the stain with consistent pressure in even motions with the grain of the wood. Always work "with" the wood and never against it.

• Rub on stain in the direction of wood grain

Follow up after about 30 seconds with the second rag, making longer sweeping strokes with the grain of the wood. Use this rag to remove any excess stain and further work the stain into the wood for a more even finish. Stain dries relatively quickly. You will want to go back and forth between the application rag on a new area and the second rag over previous areas. Blend, work progressively, and develop a rhythm involving cycling between the two parts of the process, application, and blending.

• Blend stain with second rag

Occasionally look back over your work to examine and spot areas of the finish that seem too light. You may need to apply more stain and work it into the wood better. If you spot areas too dark simply rub with the second cloth and blend the stain better. If the second blending cloth takes in too much stain it will need to be discarded. Replace it with a clean and dry cloth. The blending cloth should never becomes saturated.

You should apply at least two complete coats. Wait the recommended amount of time between coats as directed by the stain manufacturer. This is typically around 15 minutes. For a darker finish apply additional coats. Also, the more stain you apply in your initial coat will result in a darker finish.

Step 3: Apply Polyurethane in Coats

Do not apply polyurethane until the stain has had plenty of time to dry. It is best to be patient rather than apply the polyurethane too soon. If you apply it too soon, it will result in possibly disrupting the color, but may also result in a sticky finish that never seems to fully dry. I recommend applying polyurethane on the following day, or a minimum of 12 hours after the last coat of stain.

Polyurethane is thicker than stain, it needs to be applied with a brush. Although they manufacture foam brush applicators, it is recommended that you use a bristle brush that is specifically approved for use with polyurethane. The liquid needs to be brushed on the stained wood surface in even strokes and again, working with the grain of the wood. Always work with the wood.

• Apply polyurethane with a brush in long even strokes.

Your goal is to evenly coat the stained wood. You should be working in an area that is well illuminated. As you apply the polyurethane look for any areas that appear dull in the light. If an area appears dull then you either missed that area or didn't apply an adequate amount of polyurethane. Spread the brushed on liquid over the entire surface with long, even strokes. Don’t use too much or you’re likely to get runs.

While working with the brush, try to avoid wiping the brush on the rim of the can because this may introduce air bubbles. If tiny bubbles appear on the surface of the wood after a stroke with the brush, continue to brush over the area until the bubbles are gone.

Without delay you should do what is called "tipping off the finish," which is to run over the entire surface with long brushstrokes as soon as you completed coating the last area. You will brush from end to end and overlap your strokes. Because polyurethane dries quickly you will not want to poke along. Keep up a quick pace while working with the sealant. Get it applied and get it tipped off. While tipping off the finish you will not need to dip the brush in the can of polyurethane. Work with what is already on the surface unless you spot an area that you completely missed.

While drying, do not tip the wood fixture on its side. The surface needs to remain flat and upright to prevent runs. About five minutes after the last applied coat you should inspect for any drips or defects. You can make subtle adjustments at this time with additional polyurethane to a flawed area.

Again, it is important to give the polyurethane adequate time to dry. Let it dry overnight and apply the next coat the following day, or at least 12 hours later. Two coats is typically sufficient, however, in some situations a third coat may be desired. Before application of subsequent coats be sure to dust off the dry surface to remove any dust that has settled on it before application of your next coat of polyurethane.

Step 4: Smooth Finished Surface

The polyurethane finish needs to be lightly sanded smooth with very fine sandpaper (400-grit) after it is fully dried. Again, I recommend waiting a full day before sanding the finish after the last coat of polyurethane. Sand with a fine grain sandpaper. Do not sand excessively or you will sand away the entire finish. You should only need to lightly sand the finish to make it nice and smooth, more like glass. Sanding will obscure any brush strokes left in the finished surface.

Some people use a polishing compound after sanding. The compound has a fine abrasive that’ll remove any scratches left by the sandpaper. After rubbing, let the surface dry and buff the finish with a clean, dry cloth. Whether or not you want to take the extra step in using the polishing compound is up to you.