Varnish: Types, Advantages & Disadvantages

Varnish: Types, Advantages & Disadvantages

In this article, we will discuss varnish.

Varnish is a transparent, hard, preservative finish or layer firstly 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 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. The varnish 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 resulting in 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 Varnish Is 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 fiber 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 color 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 varnish will even out the final appearance of the painting, providing it 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  

Spirit varnish 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.


Spirit Varnish  


  b. Acrylic Varnish  

Acrylic varnish 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, highly transparent, and do not try to make holes in the wood as other varnishes do. Acrylic varnish 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.


Acrylic Varnish


  c. Exterior Varnish  

Exterior varnish 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 varnish 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.


Exterior Varnish


  d. Polyurethane Varnish  

Polyurethane varnish 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.


Polyurethane Varnish


  e. Yacht Varnish  

Yacht varnish is also famous for marine varnish. Marine varnish 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.


Yacht Varnish


  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.

Oil Varnish


  g. Alkyd Varnish  

Alkyd Varnish 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. The alkyd varnish can be used for increasing the wood’s colors and grain and it is clear from wood varnish.





  3. Advantages of Varnish  

The advantages of varnish are as follows:

a. It is used on unpainted wood and other woodwork to add aesthetic beauty to the surface without covering the beautiful grain of the wood.

b. To prevent the surface of the wood from the unfavorable effect of the weather.

c. It gives aesthetic beauty to the wood.

d. It helps in preventing the wood by bonding the surface.

e. It is utilized to save from hairline cracks and absorb the result of scratching and external destruction.

f. It is used in decreasing the presence of moisture between the wood and the atmosphere.

g. It gives softness and long-lasting flexibility to the material.

h. The varnish is used to withstand UV rays and doesn’t make it yellow.

i. It is cheap to buy.

j. Painted wood surfaces are varnished to increase the appearance of the paint and enhance the durability of the paint film.



  4. Disadvantages of Varnish  

The disadvantages of varnish are as follows: 

a. It has a strong and irritating odor so it needs to wear a mask while applying varnish.

b. It has low resistance to wearing and tearing.

c. It has a high chance of reacting with glues, waxes, and silicones.

d. The varnish is harder and difficult to put in the summer.


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