" " wisno wood furniture finishing: Refinishing the furniture without strip off the old finish

Wednesday, July 14, 2010

Refinishing the furniture without strip off the old finish

Process refinishing the furniture sometimes is a preferred option then buy new stuff. Although the  refinishing process actually is not a cheap job and there are many new furniture with new models and good price are available, but sometimes people still choose to refinish his old furniture. Some furniture products has historical value that make some people decide to keep them. Mostly the refinishing is done with strip the old finish and do the new finishing process to the furniture product, but in some condition there are many refinishing  processes can be done without strip the old finish.
Refinishing process without stripping the old finish is much easier and faster  process. This refinish process is done by application of clear coat and stain on the old finish. But refinish without strip the old finish is limited on the furniture products with specific conditions and  the limited color and finishing looked.  But since this refinish process is easier and faster, then we should consider of its possibility when we have to do a refinishing process.

Here are the things that need to be considered in  the refinishing without strip the old finish.
  • Finishing color.
An application of stain and clear coating can not make the color to become lighter to the old finish. Refinish without strip the old finish can only be done if the end color is same or darker than the previous finish. To darken the finish we can always do by the application of glaze or stain. But if we want to end up with a color lighter then the old finish, we have to strip the old finish.  
  • The compatibility of the clear coating
When we apply a clear coating on a existing finish, we must be sure that the clear coating is compatible with the layer underneath. (See our previous post about the compatibility of clear coating application). To find out the type of a dry clear coating is very difficult or even impossible without any data on the finishing process. But we could use a simpler principle of the compatibility of coating application, that is: a clear coatings that are dry by evaporation without  any reaction (lacquer finish) almost can be applied on all type of finish as long as it is already fully dry.  Conversely clear coatings that are dry with chemical reaction only able to be applied on the finish that is dry with chemical reaction. Principally we can apply any coat to a finish which is not resolved with solvents. But for the finish that is resolved with solvent,  the clear coating  to applied on is limited. The lacquer finish, (the nitrocellulose finish)  is the best option since it is suitable for most finishing material.
  • The finishing looked.
 We always can add the finishing effect but cannot reduce the effect that is already exist on the dry finish. Since then refinishing without strip the old finish can only be done if the new finishing looked is same or more antic or more dirty then the old finish.
  • The condition of the furniture.
The old stuff that has been used typically always has some damaged or dirty looked due to  its  application. The damages such as dent, scratch, rub off or dirty on the surfaces are common things in the old stuff. To make an antic looked finish, the damages even help us to make the appearance of antiquity. But if we want a new finishing with the clean and tidy appearance, then we have to do repairs on the goods first. And it means that we must remove the old finish, repair and touch-ups and do the re refinishing process. 

Indeed there are many things that limit to do the refinish without strip the old finish, but however we must consider the possibility when we want to refinishing the old product.

Here is the process of refinishing process:
  • Clean up the old finishing with a mineral spirit.
Mineral spirits is a solvent that does not damage the lacquer or other dry coating. Mineral spirit is the proper solvent used to clean up the oil, wax, silicon or other materials that could contaminate the coating application. Mineral spirits will also wet the surface to make the surface clean and bright and then we can see the color and appearance of the finish clearly.   
  • Do a test with paint thinner on the old finish
Find out if the old finish can be resolved or not. Take a cloth dampened with acetone or lacquer thinner and then wipe with a lightly rubbing on the finish layer. If the finish coat is not resolved then it means that the finish coat is a thermosetting film that is dry with the reaction. It means that almost all type of clear coat can be applied thereon. But if the finish layer is resolved with thinner, then the clear coat can be applied thereon is limited.  We have to use the clear coat that is dry without chemical reaction. Lacquer or NC finish is a good option since this clear coat can be applied on almost any type of dry finish layer.
  •   Do a lightly sanding on the old finish.
Sanding is always needed in every process of clear coating application. Sanding can also help clean up the old finishing layer form the dirt there. Make a light sanding evenly throughout the surface with # 320 or # 400 sandpaper  before application of the other coat, stain or glaze on it.
  •   Apply the stain or glaze, if necessary
If we want a new finishing with the darker color then we can do with the stain application on the old finish. But the application of a stain over the finish must be done carefully, Application of stain on the clear coating should not be too thick, do a lightly spray the stain, highlight, and seal with a sealer or top coat. This process can be repeated until the desired color is obtained. Glaze application can also be done to add color or to add antique effects if necessary..
  •   Clear coating application
Application of top coat is the last process of the finishing process. Top coat will protect the color and glaze underneath and form the finishing feel and looked. Use a top coat with the right sheen in accordance with the desired finish. To make a smooth finish, sometime a sealer application is needed. But the clear coat application should not be too thick, since clear coating that is too thick will affect the strength of finishing. One times or 2 times of  top coat application usually is enough to produce a flat and smooth finish.

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