Clear coats
There are many types of clear coats. And the techniques used to apply them can be very in-depth.
They are used as sealers,
protecting woods from moisture, dirt or wear. They are also used to offer clear vision to wood grains or designs that may lie underneath
as with some Faux effects.
Like Paint and Stains, clear coats have their own components. Oil, Resins, Solvents and when used in Faux
finishes water based acrylics.
Here, we are going to categorize them by their applications and their finishes, although they are chemically
categorized differently.
There are three applications in using these products.
Ø Wipe-on
Ø Brush-on
Ø Spray
After that
there are two types of finishes to consider
Penetrating
Ø Linseed oil (exterior)
Ø Tung oil (interior)
Film forming
Ø Polyurethanes
Ø Lacquer
Ø Varnishes
Ø Shellacs
-
Appearance
Protection
Durability
Reversibility
Linseed Oil
Yellow warm glow, pops grain, darkens with age
Very Little
Fairly Durable, depending on number of coats
Needs sanding out as oil is absorbed
Tung Oil
Warm glow, pops grain, lighter than linseed
Very Little
Fairly Durable, depending on number of coats
Needs sanding out as oil is absorbed
Polyurethane
Transparent, many coats can look like plastic
Excellent protection against many substances, tough finish
Durable after approx. 30 day curing period
Can be stripped using paint removers
Water-based polyurethane
Transparent
Good protection..newer products (2009) also UV stable
Durable after approx. 30 day curing period
Can be stripped using paint removers
Lacquer
Transparent, good gloss
Good protection
Hard and Durable
Completely reversible using lacquer thinner
Alkyd Varnish
Not as transparent as lacquer, yellowish/orange tint
Good Protection
Durable
Can be stripped using paint removers
Conversion Varnish
Transparent, good gloss
Excellent protection against many substances
Hard and Durable
Difficult to reverse
Spar Varnish
Transparent, good gloss
Waterproof and sunlight resistant
Hard and Durable
Difficult to reverse
Shellac
Some yellow or orange tint, depending on grade used
Fair against water, good on solvents except alcohol
Durable
Completely reversible using alcohol
Penetrating
clear coats allow for a more rustic look to woods but do not offer very good protection and little to no sheen.
Film forming clear coats when use in their designed applications offer a brilliance to their finish and superior protection. The techniques used with these finishes may consist of applying multiple coats, drying, sanding and cleaning in between each coat , until the desired thickness and sheen is achieved.
