Table of Contents
| Varnish is a transparent, hard, preservative finish or layer first utilized in wood finishing. It can also be used for other materials to protect those materials from weathering agents. The various types of Varnish are a mixture of drying oil, a resin, and a thinner solvent. |
It is a finish and protecting film provided to the wood but can be utilized on other substances too. While giving many implementations such as paint-like protection and aesthetics, the varnish will enter into the wood as well as form a protective layer over the surface.
It increases and provides comfort to the grain of the wood and withstands impact, heat, erosion, water, and alcohol. It can be utilized as a topcoat over a painted surface of the wood.
It is a mixture of resin in either oil, turpentine, or alcohol. It dries after utilizing it on the surface of wood, leaving a hard, transparent, and glossy layer of resin over the varnished surface.
The different types of varnish finishes are utilized to give a glossy surface on materials but are also made to give a semi-glossy surface by the addition of ‘Flatting’ agents. Water-based acrylic types of varnishes are more famous for their environmental and health advantages.
It is applied to the, painted surface to enhance its brightness and prevent it from weathering action. Unpainted wooden surface to brighten the ornamental aspect of the grains of wood.
1. Why is varnish applied wood?
Due to following some features varnish plays a vital role in wood to increase its durability of wood. It prevents the wood from shrinking, expanding, abrasion, and fibre erosion of wood and the harmful effects of living organisms such as fungi, bacteria, and bugs make it very important to prevent the wood.
The features of the varnish provide resistance to external factors, provide colour to the wood, highlight its pores, and provide an aesthetical look to the wood in terms of preventing the wood and durability.
It prevents the painted surface from atmospheric agents and makes the surface smooth to clean. It makes a smooth shine over the whole surface of the painting. A double layer of varnishing will even out the final appearance of the painting, providing it with a consistent look.
The dust can be collected on the surface of painted wood surface for a long time, mostly, if a painting exists in a smoky environment, thus a covering layer of varnish can be utilized to back up the painting to its previous look.
2. Types of Varnish
The following are varnish types most used,
a. Spirit Varnish
b. Acrylic Varnish
c. Exterior Varnish
d. Polyurethane Varnish
e. Yacht Varnish
f. Oil Varnish
g. Alkyd Varnish
a. Spirit Varnish
It is a type of varnish in which spirit is utilized as a solvent known as spirited varnish or French-Polish. The shellac is mixed with the spirit and the paste is used in a thin layer.
It is the types of varnish that provide a translucent finish thus providing a clear visual of the grains of the timber. These, however, do not withstand weather well enough and as such are utilized for polishing woodwork that is not kept open to the weather.
b. Acrylic Varnish
It is a quick-drying and non-toxic water-based varnish. They have good resistance against ultra-violate rays.
So, it can be utilized on inner as well as outer surfaces open to sunlight. They can be utilized on materials other than wood, so they are more adaptable than other types of varnishes.
They are clear, and highly transparent, and do not try to make holes in the wood as other varnishes do. It is water-based you can make neat and clean it with the help of water, this property makes it very user-friendly, but many times does not spread as equally as other varnishes. They are majorly found in sheen, satin, and matt finishes.
c. Exterior Varnish
It has been majorly prepared for the use of outside surfaces open to the weather agents. It has ultra–violated ray prevention so that the wood below the layer of varnishing is safe.
They are usually microporous which permits the wood to breathe and kept a fungicide to save the growth of fungi and termite.
They are similar to be very close in formulation and action to a yacht varnish, being comparatively flexible, but slow to heal even if they are touched dry comparatively fastly.
d. Polyurethane Varnish
It provides a really hard surface and is usually utilized for floors and areas which results in a lot of wear and tear. Polyurethane varnishes are also heat resistant and will provide a clear and tough finish, which is found in gloss, satin, and matt finishes.
It does not try to make a hole in the wood so they are usually primed with an oil-based varnish or a thin shellac solution. It is very useless to try and add an oil-based varnish on top of a polyurethane varnish as it will not make a bond together. In addition to their strong hardness and durability, they withstand spills of mild acids, solvents, and other chemicals.
They can not withstand UV (sun) rays, so if used outside then you need to try to find one with added UV protection or it will damage fastly.
e. Yacht Varnish
It is also famous for marine varnish. It is a varnish that was prepared to apply on boats where the main use was to make sure that water does not make holes in the wood.
To get this the varnish had to be highly adaptable. A rigid, inflexible varnish can easily get cracked as the wood is bent and flexed under the strain of the sea.
These cracks could permit water to make holes in the wood. Generally, these did not have much gloss, as appearance was a secondary feature, and little UV protection, but now most yacht varnishes have a high gloss finish based on tung oil and phenolic resins.
They are good for the utilization of outside timber, but not for a surface that gets to be hammered action on.
f. Oil Varnish
These types of varnishes are prepared by mixing hard resins like amber or copal in oil. They are very slow to dry but are durable and the hardest of all types of varnishes. They are good for utilization on uncovered surfaces that need polishing or regular cleaning and for superior works.
g. Alkyd Varnish
It is utilized on both sides exterior and interior sides. The main benefit of utilizing this varnish is good that it saves the surface against UV damage, temperature variation, and water seepage. It can be used for increasing the wood’s colors and grain and it is clear from wood varnish.
3. Advantages of Varnishing
The advantages of varnishing are as follows:
✔ It is used on unpainted wood and other woodwork to add aesthetic beauty to the surface without covering the beautiful grain of the wood.
✔ To prevent the surface of the wood from the unfavorable effect of the weather.
✔ It gives aesthetic beauty to the wood.
✔ It helps in preventing the wood from bonding to the surface.
✔ It is utilized to save from hairline cracks and absorb the result of scratching and external destruction.
✔ It is used in decreasing the presence of moisture between the wood and the atmosphere.
✔ It gives softness and long-lasting flexibility to the material.
✔ It is used to withstand UV rays and doesn’t make it yellow.
✔ It is cheap to buy.
✔ Painted wood surfaces are varnished to increase the appearance of the paint and enhance the durability of the paint film.
4. Disadvantages of Varnishing
The disadvantages of varnishing are as follows:
✔ It has a strong and irritating odor so it needs to wear a mask while applying varnish.
✔ It has low resistance to wearing and tearing.
✔ It has a high chance of reacting with glues, waxes, and silicones.
✔ The varnish is harder and difficult to put in the summer.
How to Apply Varnish To Wood?
The way to apply varnish to wood in a suitable manner is as follows:
Before beginning to apply varnish on the surface of any material, make sure that the surface is well set; varnish accentuates rather than covers marks, unwanted stains, and bumps.
The varnish is also its primer and undercoat, although in a few cases it is good to use the first thin coat with roughly 10% white spirit and water for water-based varnishes. This is particularly true if we utilize a polyurethane varnish.
Once the first coat has been placed and has dried, then it has to be rubbed down lightly and a second coat is then used.
Dust and varnish don’t mix, because all the sanding before involving the varnish will inevitably create a lot of dust. Give it time to settle and get rid of as much as possible.
If you use varnish in a dusty environment, it will stick in the drying varnish and potentially destroy the finish. If this problem occurs, then you will have to sand it down gently with fine-grit paper and then use another coat.
Unlike paint, varnishes and stains are intended to soak into the wood. You can also apply a clear varnish to the stain to improve the finish, enhance the look, and also make it more durable.
Various types of varnishes can be used with a brush, which is more usual. If you are using varnish utilizing a roller, utilize one with a short pile.
The primary coat of varnish applied should be parallel to grains of wood and another coat should be perpendicular to grains of wood to have a smooth surface and which creates varnished material more durable to weathering actions.
| Read Also: 38 Types of Wood |