Stain and Glaze

Stain

One of the most important materials and mostly required in the finishing process is stain. It is finishing material that function to shape and determine the color of a finishing. Stain is made from one or more (a blend) pigment to produce the desired color, solved with solven and added with certain resin that acts as a binder to obtain the desired properties of the stain.

The most important element of a stain is pigments, since the pigments determine the color of the stain for example red, blue, black, brown or other colors. There are many colors that can be made by selecting and blending the pigments. The method of blending and creating this stain color follows the color wheel theory that we presented in the previous edition. What we must remember is, when mixing a stain, the mixed pigments must be of similar characteristcs.

According to their types, pigments can be classified into 2 types, the organic and inorganic pigments. Inorganic pigments are pigments made out of natural materials such as natural rocks grinded or burned to certain degree of fineness. Samples of inorganic pigments known in furniture finishing industry are among others: Carbon black, Ferit yellow, Raw sienna, Raw umber, Lampblack, Titanium white, Red oxide, Burnt siena etc. While the organic pigments, pursuant to their names, are made from extract of herbs or animals. Further, thanks to the technological development in the pigment making, there are many more organic pigments made chemically out of synthetic materials nowadays. From many organic pigments, the most popular and used in the furniture finishing are dyes.

The two pigments in general have different properties. One of them is the particle size. Organic pigments have finer particles that soluble in solvent while the inorganic pigments have bigger particles preventing the materials from being solved in the solvent but dispersed. In general the difference of both pigments can be seen in the following tabel.

Properties ------Organic Pigment------ Inorganic pigment
---------------------------------------------------------
Color ------------------Bright------------- Less bright
Tinting ability--------- High---------------Vary
Density----------------Low----------------High
Light resistance--------Low----------------High
Coverability------------Low----------------High
Solvability--------------Solution------------Dispersion
Resistance against
solvent bleeding--------- Vary--------------Good


Glaze

Nowadays, people know and use also one of the stains that we call glaze. Glaze is a sort of wiping stain, namley a stain made to be applied by brushing or wiping. Actually, there have been some other wiping stains but usually, what we know now as wiping stain is the stain usually applied by spraying but modified in such way so that it can be applied by wiping. Glaze is specifically made to be applied in different way and produce effects that are different from the other stain.

One of the important characteristic of a glaze is that it can be wiped or brushed easily and left on the surface at certain desired thickness. Glaze is usually made out of organic pigment added with an alkyd resin and oily solvent that does not solve sealer or lacquer. So glaze is very easy to wiped out or added without necessarily destructing the sealer under it.

Glaze is different from the other stains in its application method and it looks. Glaze is applied on a sealer or wash coat (a thin sealer) with a purpose of filling the color to the wood pores and fibers. Application of a glaze will display the beauty of the wood fibers and pores and enrich and deepen the color of the finishing. Glazing by brushing also helps overcome the difficulty in the process of coloring narrow depressions that can not be reached by sprayer, for example in graving, corners or grooves. By using the glaze brushed evenly on the narrow depressions the parts will be easily and uniformly filled with color.

Other use of a glaze is to create special effects to the finishing such as antique, dirt, darker color effects on the corners or other parts causing the furniture looks older. A Glaze can also be used to make special color such as marble colors or imitating wood fibers if required. In combination with some colors, glazes can also create the dirt finishing effect to fill the depressions, profiles or corners of furniture.


Woodmag, No. 15, Jan 2008
Magazine for Ekamant's Premier Customer