Polyurethane is basically a substance that is used for coating woods. The substance is nothing but oil or water based plastic resin that saves wood from getting damaged due to moisture.
On the other hand, Varnish is another type of wooden finish, derived from oil, solvents and resins. This is basically a traditional type of wood finish and that is why it is often misused as the generic term for all kinds of wood finishing. The following section will discuss about Varnish vs Polyurethane.
Differences between varnish and polyurethane
The differences between varnish and polyurethane are shown in the below comparison table.
Varnish is produced from oils, resins and solvent. Mixtures of these in various ratios create various kinds of Varnish.
Polyurethane is basically oil based or water based plastic resin.
Varnish dries slowly once applied on the wood. In normal weather conditions, it takes around 6-7 hours to dry completely.
Polyurethane dries in a little slower pace, if it is oil based. However, water based polyurethane dries at a quick pace under normal weather conditions.
It is lesser durable though it is good against UV rays.
It is highly durable though it has a poor performance to display against UV rays. It acquires cracks so easily if exposed under sun constantly.
Varnish is applied through brushing and for applying it properly several layers of coating have been required.
Polyurethane is easy to be applied in comparison with Varnish. Not many layering is required for applying – two to three layers would be enough.
Varnish is little toxic though it is mostly considered to be safe.
Polyurethane is considered as highly toxic, especially water based polyurethane has high toxicity to display.
It is considered as traditional wood coating or finish. It is cheaper than new types of wood finish.
It is expensive, but cost effective. You do not need to put 5-6 layers of coating – only 2-3 coating will be enough.
It is mostly used for finishing outdoor wooden furniture as it is good to protect UV damages.
It is not used for outdoor purposes. It is mainly used for indoor wooden furnish finishing purposes.
Both Varnish and Polyurethane have their pros and cons to display. This is why they are used for serving various purposes by the furniture manufacturers.