When you go to a DIY store to buy a can of paint, you will see various products available, which can be very confusing.
Here, we will explain the purpose of coating a woodwork, key points when choosing a paint product, and some common options such as paint, varnish, stain, polyurethane finish, wax, and oil.
If you would like to go directly to the description of each type, click a link below.
Purpose of coating a woodwork
There are many objectives for painting or applying a finish to your project, such as to color, to give a sheen appearance, and to protect the wood surface from damages and stains.
Since wood is a natural material, it can be strongly affected by humidity, ultraviolet radiation and other factors.
- It swelled due to humidity or moisture, or mold was generated.
- It deteriorated due to exposure to rain and wind.
- Drying caused warpage and cracks.
- Discoloration occurred when exposed to direct sunlight.
Deterioration and weathering are inevitable since wood is a natural material. However, by applying a coating, the surface can be protected to keep your woodwork durable to scratches, corrosion, and discoloration.
Key points when choosing a paint or wood finish
When choosing a paint or wood finish, consider at least the following points:
□ If you want to leave the grain of wood or hide it with a paint
□ If you want to have a sheen appearance
□ If the object is for indoor or outdoor use
□ If you prefer to use a paint that is easy to handle
□ If you have sufficient time to dry
In general, if it is a frequently-used object, or an object used outdoors, exposed to rain and wind, or if it is installed in a humid place, applying a coating is important to make it durable.
If not used in such place, you can decide depending on your preference of final appearance because it is also possible to use a woodwork without painting.
Water-based paint or oil-based paint
There are two types of paints, water- and oil-based paints, and the difference is in the solvent as explained above.
Since a coating film is formed on the surface as the solvent dries, it will be difficult to feel the original texture of wood.
To explain in more detail, depending on what resin is used to make the coating, it can be divided into oil-based paint, lacquer, synthetic resin paint, and shellac varnish.
You should choose which one to use, considering the drying speed and the hardness of the coating film you need.
There are water-based and oil-based varnishes.
Varnish creates a coating on the surface of the wood like a paint, but it is basically transparent.
It is often used as a topcoat for stain or as a gloss finish by applying only varnish over a wood surface to emphasize the grain of wood, but there are also colored varnishes.
The coating film is thin and vulnerable to expansion and contraction, so it may not be suitable for outdoor use.
For outdoor use, you should choose an outdoor varnish.
Also, the coating film formed on the surface will impair the texture of wood.
Polyurethane finish (polyurethane coating)
This finish will create a coating with polyurethane resin.
There are water-based and oil-based polyurethane types, and also various products are available, such as a polyurethane varnish and polyurethane lacquer.
Polyurethane finish can create a hard coating film, and is resistant to humidity and highly durable. Even if the surface gets dirty, it can be easily wiped off, so that the maintenance is very easy.
However, partial repainting is difficult. Once some parts are peeled off, the object may have to be used as it is.
In addition, it is sensitive to heat, and if you place a hot pot directly on a polyurethane-painted table, it may leave white marks. It is an important point to keep in mind.
A stain is a colorant that color a surface while leaving a grain of wood. It can be used for indoor and outdoor woodwork. It penetrates into wood and colors it, but it does not form a coating film.
Since stain does not protect the wood, it is common to apply a varnish or other top coat. This has the purpose of preventing color transfer, glossing, and giving a protection.
Note that stains need to penetrate the wood, it is not possible to apply stains over paint or varnish.
When the main raw material for the wax is naturally derived, beeswax or other natural wax is used, and there are also petroleum-based waxes. Unlike paint and varnish, wax does not form a coating. It slightly soaks into the wood, and the rest of the wax that does not penetrate remains on the surface, preventing it from drying and getting dirty.
Wood materials are capable of regulating humidity by inhaling water vapor when the humidity is high and releasing it when the humidity is low. We sometimes express it as wood breathes. However, if you create a coating film with a paint or varnish, the wood will not be able to breathe. With wax, you do not have to worry about losing the advantage.
Also, if it fades, it can be applied again.
It is ideal for a finishing without hiding the grain of wood, and gives a warm look without losing the texture of the wood. By applying wax over and over again, the object will gain a rich texture and a sense of quality.
However, since wax does not form a coating film, it is difficult to create a durable protection and it is also vulnerable to heat. If you put something hot directly on the surface, it will leave a mark.
With wax, you cannot expect to have a long-lasting protection effect after applying it once. Instead, it brings a joy of maintaining your woodwork while overcoating with wax at a regular basis.
The fact that it is vulnerable to wear may seem as a complete disadvantage, but a wax-coated surface is also easier to repair than a paint or polyurethane coating in the case of small scratches.
Most of the oil penetrates the wood when applied. The permeated oil reacts with oxygen and hardens, protecting the wood from the inside.
Since no coating film is formed on the surface, this finish will leave the original grain and texture of the wood. It also does not interfere with the breathing of wood.
Oil has many similarities to wax. It does not interfere with breathing, it is not durable, and it needs to be overcoated as a maintenance.
The difference is that the oil penetrates the interior more than wax, achieving a moist finish that looks like it is wet with water.
We explained some key points to decide a paint or finish, difference between a water- and oil-based paints, and characteristics of paints and finishes such as paint, varnish, wax, and oil.
We hope you find this article helpful.
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