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Lacquer, Varnish And Polyurethane Finishes Explained
There are two major groups of wood floor finishing products. The first type referred also as penetrating oil finishes, can soak into the wood and protect it from within. The second type, which includes varnishes, lacquers and polyurethane lacquers, is not absorbed but forms a protective film on the surface of the floor. In terms of pure durability and toughness, surface finishes are superior in every aspect.
Before we begin, let's take a look at lacquers, varnishes and polyurethane products and determine what exactly is each of them, what is it made from of and how it works.
What Is a Varnish?
You have to understand that in many ways the terms 'lacquer' and 'varnish' are used as synonyms. We are talking about two different floor finishes which display such similar qualities that most people don't make a difference. 'Varnish' is now used as a general term for a finish protecting the surface.
Varnishes are transparent, have tough protective finish and consist of three basic components – oil, solvent and resin. Different types of varnishes are created by modifying and changing the percentage ratio of each of those three elements.
The varnish is a glossy, transparent and harder than lacquer but tends to crack. Once that happens, anything – from dust to liquid spills can go through it without a problem and damage the floor. This weakness makes it inferior to the lacquer in terms of durability.
What Is a Lacquer?
The word 'lac' comes from the Portuguese name for the famous lac insects (Laccifer lacc). The secretions of those insects are used to make both lacquer and shellac finishes but they shouldn’t be confused with each other.
We already explained that varnishes tend to crack a lot. This is because they are harder and thus - brittle. A lacquer is ‘softer’ and isn't as susceptible to UV damage. It is simply a more modern product which lasts longer and seals the floor better. As a result, varnishes are replaced by lacquers on the market because while both products perform the same function, lacquers excel at it.
What Is a Polyurethane Finish?
There are two main variations of polyurethane - water and oil-based. In terms of strength and durability, polyurethane lacquers are arguably the strongest floor finish on the market. The only exceptions are aluminium oxide finishes but they can only be prepared in factories and never on-site.
Water-based polyurethane lacquers are incredibly popular because they contain little VOCs (volatile organic compounds) which are considered harmful for human health, provide clear, transparent finish and dry faster than their oil-based counterparts. However, they are also more expensive and provide lesser protection than oil-based polyurethane.
Oil-based polyurethane contains relatively high amounts of VOCs and slowly turns yellow as time passes. The ageing process also makes them unsuitable for stained floors and especially grey and whitewashed surfaces. Oil polyurethane requires fewer coats compared to waterborne polyurethane and given that it is cheaper as a whole can be a good option if you want to save money.
Both lacquers, varnishes and polyurethane finishes are still used today for furniture and this may cause some confusion. In past, varnishes were also utilised as a floor finish but no more. They simply lack the qualities needed to compete with modern products.
Lacquers, on the other hand, still have their place and as far as floor finishing is concerned, the terms 'lacquer' and 'varnish' have merged and become synonyms. The general public will still call them varnishes and the people of the trade – lacquers.
Polyurethane is simply a lacquer ingredient, not an entirely different line of products. Polyurethane lacquers are the most durable of their kind and continue to be the most desirable one for obvious reasons. We can only recommend them as an excellent way to protect your floor.