Plan ahead before you start to avoid problems or rework.

While woodworkers are familiar with the old adage of “measure twice, cut once” to help them avoid making construction mistakes, a similar thought applies to finishing – only in this case, instead of measuring, what’s required is simple: think before getting started. It is important to look at each piece that you want to finish and to spend a little time planning out just how you are going to proceed. Having to repair or re-do a finish can be just as problematic as fixing a wrong cut.

This is especially helpful if you are trying to match an existing finish. Stop to consider what “clues” may be apparent in the piece. Is the finish transparent, translucent or opaque? Is the stain a dye, pigmented or a combination of both colorants. Was it glazed or shaded?

You need to think about these questions before you jump into finishing your work. Here’s one trick you can use to start: On finished wood samples that you want to match, you can lightly sand the finish and then check for stain, toner, fillers, glazes and shaded coatings that may be exhibited on the sandpaper.

A simple trick to duplicate a finish is to sand the finish and see what’s on the abrasive. These four panels show, clockwise, the original sample, after sanding the clear coats, after sanding through the stain and down into the paste wood filler.

If you are doing repeat finishes that you will duplicate in the future, another trick is to make up a “step sample” on a stick or a panel. This will enable you to check to make sure that each step you do is consistent with the original. If the finish is running off when you compare it with the step sample, you can then make some adjustments.

Step samples are really useful if you are using more than a one-color medium in your finishes. For example, stains that are sprayed and not wiped can change the final color; colored glazes that are not brushed out uniformly will change the final color, and so will doing less or more passes of a shading stain. It also is a known fact that applying a clear coat on white wood will change the wood’s appearance. The same is true when you stain the wood and then apply clear coats over the stain. The stain’s color may be altered, changed or slightly shifted.

Your final finishes will not match unless each step in the process is done the same way throughout the finish. If you are having a problem, you can identify exactly which part of the process is different by using a step sample.

(By the way, it is important that all your color mediums, such as stains, toners, glazes and shading stains, be thoroughly mixed during any process for color continuity.)

Even when you are not worrying about duplicating a finish and do not need to create a step sample, I always advocate making a finish sample to test-run a new finish before you do the final piece.

Even though making up colored samples takes time, it’s time well spent. I also believe that making up complete start-to-finish samples is a terrific way to learn how to finish.
As you gain more experience, you will not need to make up samples for every finishing job you get. The more you get to know the one-step finishes, the less you will need to do samples. But whenever you are in doubt, always make up a start-to-finish sample.

It is all part of the “think twice, finish once” credo.

Mac Simmons is a freelance writer and 50-year veteran of the furniture finishing, refinishing and restoration trades. Mac has written articles for woodworking magazines in the U.S. and in the UK, Austria and Canada. Questions may be directed to him in writing c/o CWB, 400 Knightsbridge Pkwy., Lincolnshire, IL 60069 or via e-mail c/o [email protected].