To furniture workers, artists, and other artisans, the art of top coating isn’t anything new.
Applying that clear extra layer gives materials that glossy look that enhances their appearance and increases their ability to be printed upon. It also reduces the rate of moisture permeation into the underlying coats, increasing their lifespan. Top coats usually provide a protective layer for paintings, ornaments, and decorative objects, as well as furniture and wooden surfaces.
The benefits of and reasons for top coating are numerous, but what is the best top coat?
One of the most commonly used top coat options is Shellac which is a natural top coat that’s well known for its versatility. It’s used on food, in nail polish, and on furniture. For woodworkers and artisans, shellac is one of the easiest and most affordable finishes out there.
Unfortunately, shellac doesn’t do well on its own and needs another finish over it. In this article, we’ll be going over shellac, its properties, pros, and cons, as well as the best finishes over it.
What is Shellac?
Shellac is a natural top coat made from processing a resin – which is secreted by the female lac bug in India and Thailand – and combining it with alcohol. Its name comes from a creative combination of the words “protective shell” and “lac bug”. Shellac is usually dried, hardened, and sold as amber flakes before being dissolved by users in alcohol to make liquid shellac.
The uses of shellac are numerous. It can be used as a natural primer as well as a tannin-blocker, sanding sealant, and odor-blocker. As a high-gloss varnish, shellac is used in the food industry as well, serving as a food glaze for candy and edible cake decorations. In the furniture industry, it is used as a wood finish and a brush-on colorant.
Aside from adding a protective coat to products, it can also add a warm amber color to wood, which improves the general appearance and feel. It is important to note that, as a natural thermoplastic, Shellac is heat sensitive and will become soft and flow when heated, only to harden and become rigid again at room temperature.
Shellac enhances the natural grain of the wood and is very versatile and easy to use. It adds a smoothness to the surface of wood, acts as a sealer and moisture barrier, and does not create the “plastic” appearance of polyurethane or lacquer.
With that being said, is shellac the best finish for wood? To get to this answer, we must first consider its pros and cons.
Pros of Shellac
- Easily applicable: As mentioned earlier, Shellac is versatile and easy to use. The nature of Shellac makes it a very easy finish to apply, which is one reason why it’s popular among DIY craft workers. Dissolved Shellac is usually applied with a fine-bristled brush or rubbed on with cloth; an activity everyone is capable of doing.
- Natural: The status of Shellac as a natural glaze is one reason it’s common in so many different industries. In woodwork, this plays a vital role in acting as a moisture barrier for wood. Aside from offering this protection, shellac doesn’t leave the wood looking plastic. Shellac gives the wood a nice amber shine, which not only makes it look nice and mellow but also enhances its natural grain. Another important natural feature of Shellac is that it is eco-friendly and produces no fumes when applied, therefore saving users the stress of buying masks.
- Quick drying:Shellac’s quick drying nature makes it easy to work with. Shellac dries in about thirty minutes, whether sprayed, brushed on, or rubbed on, allowing users to finish their work quickly.
- Easy to repair: Old shellac can easily be scraped off with sandpaper or, preferably alcohol, and a new coat can be applied where the old coat was. It dissolves and easily blends into the spot where the former layer was.
- Relatively long-lasting: Shellac is highly resistant to UV rays and as a result, does not fade or turn yellowish over time.
As a wood finish, Shellac is one of the most versatile and easy-to-use top coats out there. It is easy to apply, natural, long-lasting, quick-drying, and easy to repair. Shellac adds smoothness to the surface of wood, enhances the natural grain of the wood, and gives it a nice, clear shine.
However, despite all its pros, Shellac is not without its disadvantages.
Cons of Shellac
- Durability: The thermoplastic nature of Shellac makes it a less durable finish than others. Because it’s not heat-resistant, it’s prone to damage. Placing hot pots, pans, and even mugs will leave a white ring in the area. As a precaution, avoid placing things on it.
- Sensitive to water: It is not waterproof, but it can withstand water for a while. However, using Shellac in areas where water is used a lot, i.e., bathrooms and kitchens, isn’t the best idea. Watermarks or humidity on a shellac-coated surface take away the glow and give it a whitish stain.
The pros of Shellac clearly outweigh the cons, but does that make it the best finish out there? Sure, it may not be very durable and its sensitivity to water takes some marks off its good name, but Shellac is long-lasting, easy to apply and it dries quickly.
Shellac might be great, but, on its own, it tends to be more of a nuisance than not. Its shortcomings make it less scratch-resistant, and susceptible to heat, and the fade from water prints makes it look unattractive. Shellac often needs to be coated again with other finishes to fix the durability issue.
Best Finish over Shellac: Options and Which to Use.
Because of these shortcomings, shellac is often combined with other top coats for maximum function. It is important to note that any finish can be used over shellac, provided it is a dewaxed shellac product, as natural shellac is already full of wax. That said, here are some finishes that can be used over shellac:
Essentially a liquefied plastic, polyurethane comes in both water and oil-based options and also comes in a variety of finishes, and low sculptures, from satin to glossy. The most popular of the two main types is water-based polyurethane because of its low toxicity and low odor.
Water-based polyurethane also dries much faster than oil-based polyurethane. Unlike shellac, polyurethane is water-proof, giving it an edge over the former. However, like shellac, water-based polyurethane doesn’t hold up well to heat and chemicals.
It’s good for bookcases, wood sculptures, and cabinetry. Polyurethane can be used over shellac to improve the durability of the product.
Varnish is a clear coating that usually has a yellowish shade but also comes in different shades. Varnishes do the same work shellac does, protecting wooden surfaces, paintings, and various decorative objects.
It is an inexpensive, exceptional finish that is waterproof, so it can be used instead of shellac. And because of its waterproof nature and high resistance to ultraviolet light. Varnish is often used on boat decks, beach chairs, etc. It is also easy to apply, and application is done with the use of a natural-bristle brush.
However, alcohol-based varnishes are hazardous to health, and they’re more frequently used than normal varnishes because they last longer. As a result, residents have to evacuate the premises and applicators have to put on masks to apply it.
Oil-based varnish can be applied over shellac without any problem, and this time the shellac doesn’t even have to be dewaxed. Combining coats of oil-based varnish over a coat of shellac will produce an attractive and durable natural finish.
This is a clear liquid that is usually made from a combination of resin extracted from trees and wax. Lacquer is applied to wood and metal as a finish and is commonly used on high-end furniture. Like shellac, lacquer is quick-drying and long-lasting.
As a bonus, it is water resistant and will not get watermarks. Lacquer is also heat resistant and will not melt from having a hot mug placed on a lacquered surface. However, lacquer is difficult to apply; applicators need proper equipment and an area free from people to spray as it gives off a toxic gas when sprayed. It is also difficult to get rid of scratches and dents on lacquered surfaces.
Lacquer is another finish that can be applied over shellac. Lacquer gives shellac-coated surfaces more durability while maintaining that nice, glazed-over look. However, sanding paste is required to get a smooth surface before lacquer is applied.
Tung oil is a natural wood finishing oil used for furniture, cabinetry, kitchenware, ship decks, etc. Tung oil protects wood, is waterproof and long-lasting, it is also praised as the best natural finish over shellac and linseed oil.
Woodworkers use tung oil like shellac as a hand-rubbed finish, and it goes well over shellac. For starters, it shrinks and wrinkles as it dries. Therefore, woodworkers often go for trusted tung oil or tung oil-based varnishes. Tung oil also looks less attractive as a finish than shellac, however, combined they bring out each other’s strengths.
Out of all these options, which is the best finish over shellac?
The answer to that is simple; a tung oil-based varnish. As stated earlier, despite all its pros, shellac is not very durable nor water resistant; two very important features to consider when looking for top coats. Among natural finishes, tung oil trumps shellac and linseed oil in hardness, durability, and water resistance. The most popular modified tung oil finishing is Waterlox ORIGINAL Sealer/Finish.
Furniture makers and artisans are advised to finish over shellac to create a smooth, clear sheen while simultaneously improving its durability and making it waterproof.
Shellac is not a perfect top coat but combined with other finishes, it could yield amazing results.