Shellac is indeed a popular choice among wood finishers for sealing and enhancing wood. Its fast-drying nature and ease of application make it a versatile option for various woodworking projects.
Unfortunately, many DIYers and newbie woodworkers are still unsure if you need to sand between coats of shellac. I took the time to investigate, so tune in to know what I’ve found out!
What is Shellac and When Do You Use it?
For starters, shellac is a non-toxic and versatile classic wood finish that can enhance the appearance of natural grain, all while adding a layer of smoothness without making it look plastic-like.
Once it dries and hardens, shellac is a natural, safe finish. It is made from resin flakes that are secreted by a lac bug (Asian native insect) and are dissolved in alcohol.
This finish is easy to apply and can leave behind an attractive finish, making it appealing to DIY lovers and professional woodworkers.
Shellac works exceptionally well on mahogany, walnut, and fine veneer. It can polish well and is the basis for classic and traditional French polishing on fine wood furniture.
As for when you should use it, remember that shellac is not a durable finish. Exposing it to elements can very easily cause damage to it. That reason is why shellac is reserved chiefly for decorative indoor pieces.
Another thing about shellac is that it bonds exceptionally well with anything you try! That characteristic is handy, especially if you want to coat a wood piece in water and oil-based finishes.
Shellac is typically used to replace wax when coating food to make them more appealing.
Also, note that polyurethane stain does not bind well with shellac because of the wax content. Polyurethane is a resin class obtained as the product reaction of isocyanate with a polyol. Although, you can avoid that by purchasing dewaxed shellac.
Cut of Shellac
You can mix shellac with denatured alcohol in different and varying concentrations, mainly depending on the thickness you prefer for the finish. 16 oz, or a pound cut, pertains to the number of shellac flakes you include or mix with a gallon of alcohol.
For instance, if you aim to create 16 oz or a pound cut with a gallon of alcohol, you must include 16 oz or a pound of shellac flakes. That will give you a thin mixture.
48 oz or three pounds of shellac poured into a gallon of alcohol will undoubtedly give you a thicker cut, about a whopping three pound or 48 oz cut.
The thickness of the mixture will depend primarily on what and where you need to use it. It is far easier to apply thin coats than thick ones.
Unlike thin coats, thick mixtures will leave behind brush marks on the surface. Also, thinner cuts of the shellac will give you a glossier and smoother finish.
How Do You Get Shellac?
The shellac finish is a relatively common product in the woodworking industry, especially in the furniture department. You can find it in any hardware store!
It’s also available on Amazon if you prefer online shopping. Another common way to obtain it is by purchasing from a direct shellac producer or supplier.
Shellac’s Cost & Color
Shellac is relatively cheap and inexpensive. Cans of shellac can range from around $10-$60, mainly depending on the can size. However, you must buy a larger can to create and complete a large wood project, like a deck or cabinet.
Most shellac wood finish in the market comes in amber, though other colors are available too — with white and orange shellac being among the most popular.
White shellac is mainly utilized on light wood and is typically thinned using denatured alcohol as a sealer. Meanwhile, orange or amber shellac is historically the most known, mostly applied on dark woods.
Why Do You Need to Sand Between Layers of Shellac?
Shellac dries quickly and has a relatively straightforward application process to follow. Typically, woodworkers sand between each individual coat of wood, gradually improving the surface’s adhesion. That is the usual process for most wood finishers. Now, what about shellac?
Sanding between shellac coats is highly necessary to help improve the surface adhesion of the prior applied shellac coat.
Doing this can also help remove flaws, defects, nibs, and other surface imperfections. Sanding before the following coat can help ensure that minor flaws will not compound or build up over time.
Only do light sanding between shellac coats to ensure you achieve a smooth finish without causing any damage to the former coat.
Another thing to note is that sandpaper (coarse grit) can cause damage and leave behind flaws on a shellac coat, making the smooth surface ugly. Never perform any forceful sanding since it can burn the previous coat, creating a solid mass with an unappealing appearance.
Suggested Read: How to Properly Apply Bulls Eye Shellac
What Happens When You Sand Shellac
Other finishes like varnish and lacquer also sand between coats, so this process is not unique or special to shellac. Most finishes would also look much better after lightly sanding them between coats.
Most carpenters and woodworkers sand in between coats of shellac to primarily remove any imperfections. They also do so to make the new coat stick better to the previous shellac coats.
The sanding method will make the surface of the finished product much nicer. Sanding each shellac coat as you go can help prevent the buildup of flaws over several shellac coats.
To apply shellac, ensure you minimize the runs, drips, and nibs since a thick coat of shellac would take longer to cure and dry. They also would make the surface splotchy.
Sanding between coats of shellac would help protect the surface from blemishes and make it easy for the next coat to bond with the previous coats, creating one layer.
How Long To Wait Between Coats?
The temperature and ventilation of the workshop are the things to consider when it comes to predicting how fast a coat of shellac dries.
Given the right temperature and ventilation, one layer can dry as fast as 30 minutes! However, it would still be best to practice caution and wait a few more hours to apply shellac again.
The recommended waiting time is four hours between shellac coats to allow the finish to settle and dry thoroughly. Applying shellac coats too early will indeed affect the overall quality.
For those living in highly humid areas, the coats of shellac will dry much slower. It might take about twelve hours to dry completely! If that were your case, let it dry overnight.
Should You Sand The Final Coats Of Shellac?
Sanding the final coat of shellac with 180-220 grit sandpaper is not necessary, but it can be done to help remove imperfections and achieve a smoother surface if desired.
This is optional since the sanding smothered a few coats and gave them good adhesion. For that, the last coat no longer needs a good adhesion.
This is why sanding the last coat is only recommended and not necessary. The final coat would stick well to the previous coat of shellac.
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What Grit of Sandpaper to Use Between Shellac Coats
If you sand between coats of shellac, ensure that you use fine-grit sandpaper for better results. It would be best to sand between coats using sandpaper with a grit range of 180-400. In doing this, the next coat will have a better chance of sticking to the wood surface.
To achieve optimum results, here is a summary of the types of sandpaper grits you should use for every coat.
Shellac Coat | Sandpaper Grit |
First coat | 180-220 |
Second and third coats | 320-400 |
The final coat | 180-220 |
How Do You Sand Between Coats Of Shellac?
In addition to understanding the fundamental aspects of sanding between coats of shellac, delving into the process in greater depth is beneficial.
It is essential to emphasize that before beginning the application of shellac, it is crucial to prepare the surface thoroughly, ensuring it is as smooth as possible.
There are two ways to apply the coats of shellac — using a brush or through padding. Using a Chinese-style soft-bristled brush is ideal when you choose the brushing method. You can easily find one in a paint store for a low price.
Dip the brush with shellac or apply a few drops, scrape any excess, and gently apply it to the surface. After applying the first coat, let it completely dry for about 4 hours before you lightly sand it with a finer grit.
Do not sand against the wood grain using an abrasive paper [1] since it can appear in the final result. Sand between coats of shellac by following the wood grain direction without scratching or damaging the surface.
Remember to avoid sanding the shellac coat if it is still wet since it can clog your sandpaper and leave behind a surface that looks blotchy. If you prefer for the piece not to be glossy, you can lightly buff out the last and final coat using 0000 steel wool to eliminate the sheen.
Another method for applying shellac is padding, which involves soaking an old sock with shellac, wrapping the soaked part inside a muslin or cotton cloth, and gently padding or rubbing it onto the surface.
If the pad starts to stick and makes the application difficult, you can apply mineral oil to the old sock to lubricate it. This technique allows for a smooth and even application of shellac.
How Many Coats Of Shellac You Need to Use?
Apply at least four shellac coats on the furniture or piece for the best results. Aside from protecting the woodwork from elements like water and decay, shellac can also help improve the natural light blonde color of your product.
Just let each layer dry completely and only do light finish sanding. For your final coat, sand thoroughly and let it dry for at least 24 hours, then wait three days before you use it.
Sanding Shellac Between Coats: Tips & Tricks
Here are valuable tips to follow when sanding between shellac coats:
- Only use fine-grit sandpaper to sand the surface to ensure the next coat sticks to the previous one.
- Apply four coats to attain the desired result.
- Use good quality sandpaper from a well-branded manufacturer.
- It is required to sand your first layer, while the final one tends to be optional.
- Evenly and gently sand the surface.
- Let the previous layer dry completely before applying the next coat.
- Sand well between layers to avoid leaving behind any solid mass or imperfection.
Conclusion
Yes, it is advisable to sand between coats of shellac. While it may be a repetitive and time-consuming process, sanding between coats helps achieve a smoother finish and ensures there are no imperfections on the surface.
This step is essential for obtaining a flawless and professional-looking result in your woodworking projects.
You've probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.
Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.
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