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The
basic way to change a wood’s color is to apply stain. Besides the
obvious variances in color, commercially available stains differ in four
major ways.
Type of
colorant
There are two types of colorant used in stains: pigment and dye. Pigment
is finely ground natural or synthetic earth. Dye is a chemical that
dissolves in a liquid. Everything that settles to the bottom of a
container is pigment, and all the color that remains in the liquid after
the pigment has settled is dye.
Pigment is better at highlighting grain if
the excess is wiped off, and at obscuring the wood if the excess is left
in any thickness on the surface. Dye is better at changing the color of
wood without muddying it – especially dense woods like maple. Some
stains contain only dye, some contain only pigment, and some contain both.
Amount of
colorant
Stains differ in the ratio of colorant (pigment and dye) to liquid
(thinner and binder). The higher the ratio of colorant in the first coat
you apply, the darker the stain will make the wood. You can control how
dark you color the wood in one application of stain by adding pigment or
dye to increase the ratio or thinning to decrease the ratio.
Type of
binder
Most stains contain a binder, which seals the pigment or dye into the wood
or onto its surface. Binders are oil, alkyd, oil/alkyd or waterborne
finish. The biggest difference among binders is drying time – oil dries
slowly, alkyd dries rapidly. But also important is waterborne stain’s
characteristic of raising wood grain. Some dye stains, usually identified
as “non-grain-raising (NGR)” or “water-soluble” don’t contain a
binder.
If a stain contains a binder, every coat
after the first remains on top of the wood; it doesn’t go into the wood.
Pigment is these stains obscures the wood if some is left on the surface.
Dye in these stains is fairly transparent. Dye stains without a binder
continue to add color into the wood and darken it more with each coat.
If you apply a pigment or dye stain over a sealed
surface and leave it, the stain is called a toner or shading stain.
Thickness Most stains come in liquid form, but some are thick
gels. Gel stains are useful for reducing blotching on small or
one-of-a-kind objects made of woods like pine and cherry, because gels
don’t penetrate into the wood. |
