These terms are often interchanged, and although they serve the same purpose it’s important to know that there’s still a big difference between varnish, lacquer, polyurethane and shellac.
If you are truly faithful to the environment, use this natural product. Shellac is a combination of resin secreted by the female lac bag and a solvent (most often, alcohol). It is completely safe once it has dried and gives an amber colour to the surface. However, white spots can form when they get in contact with a hot object, so it’s not the best option for the kitchen.
It is usually available in a liquid form but you can also find shellac flakes that should be melted.
Basically, polyurethane is plastic in a liquid form until it dries. It can be water or oil-based that can be matte to glossy.
The water-based version is a crowd favorite due to its minimal level of toxicity and gentler odour. It also dries faster. However, it has low resistance to heat and strong chemicals. Consider using it on surfaces that are not subjected to extremes.
Oil-based polyurethane beats the water-based version when it comes to durability. It can endure higher temperature which makes it a respectable candidate for kitchen use. It is light coloured which means it can draw the beauty of the wood surface.
Experienced carpenters advise that you work in a well-ventilated area wearing a respirator. Perform the application using a soft-bristled brush and follow the manufacturer’s instructions. Take note that oil-based polyurethane takes more time to cure so plan your project accordingly.
Although both forms can be smeared over latex paint, the oil-based version can create a yellowish shade, particularly to light colours. To protect the surface without hurting the appearance, go for a water-based coat.
Thankfully, polyurethane is also sold in spray cans which allow easier application. Most woodworkers prefer to wipe it on using a rug for a friendlier look.
The term vanish is often used as a general term for the top coat. Due to its higher solid ratio, it offers a stronger protection. For outdoor projects, use spar varnish. Aside from keeping the moisture and pest away, it also provides protection against ultraviolet rays. It’s also a perfect choice for items that constantly exposed to water such as beach chairs and decks.
Homeowners who are planning an ultra-modern atmosphere should use lacquer because of its intensely glossy finish. Its durability and resilience are excellent but it is not completely safe from discolouration and scratches. The final product is smooth because lacquer is thinner than other finish and is applied using an HVLP (high-volume, low-presser) sprayer.
If you are unsure what to use for your next project, contact us. We are a network of trusted Carpenters in Australia.