Facing challenges with achieving a resilient, glossy finish on your woodwork? If you’re planning to put shellac over lacquer, we have you covered!
In this guide, we’ll delve into shellac’s formulation, and if it can provide an enduring, aesthetically pleasing finish for your woodwork.
About Shellac: The Miracle Finish
Shellac, a resin from lac bugs, has been used as a wood finish and sealant for centuries. When mixed with alcohol, shellac dissolves smoothly and builds up faster.
Its history dates back 3,000 years, with various types and ingredient ratios impacting its properties, such as durability and pliability.
Pros of Shellac
A second coat of lacquer dries quickly in 30 minutes, crucial for attaining a polished, expert-like appearance.
Easy to Repair
In case of errors, just sand the affected portion and redo it without needing to remove the finish from the entire furniture piece to correct a minor issue.
Contrasting lacquer, shellac eliminates the need for abrading between layers, resulting in time and energy savings because of its very thin surface.
Not as Durable as Lacquer
Shellac is susceptible to liquid damage as well as heat or alcohol exposure.
Not as Widely Available as Lacquer
Acquiring shellac might necessitate purchasing it online or through a niche retailer.
Lacquer, a durable finish, dries when the solvent evaporates. It can be applied over stained or painted surfaces and buffed to a high gloss finish.
Originating in Japan around 700 BCE, it became popular in Europe in the 16th century for furniture and instruments. It is different from varnish but has a nice finish.
Lacquer, a transparent finish, dries rapidly and allows for application in slender layers.
Moreover, lacquer is robust and resists moisture, making it an excellent choice for safeguarding raw wood against moisture-related deterioration.
Lacquer is also good for finishing surfaces subject to heavy wear, such as table tops or countertops.
Difficult to Apply
Using lacquer demands caution, as achieving an even layer can be challenging. Inattentiveness may result in a streaky or irregular finish.
Harsh Off-gassing (First Application)
Upon initial application, lacquer emits harmful fumes, posing a risk to you and your loved ones. Ensuring proper ventilation in the work area is crucial for safety during lacquer application.
Turns Yellow Over Time
Lacquer may develop a yellow hue over time, particularly when exposed to sunlight, potentially impacting your furniture’s aesthetic appeal.
Hard-to-remove Scratches & Dents
After lacquer application, addressing scratches or dents can prove challenging. Incautious handling may result in damage to the finish.
Can I Use Shellac on Lacquered Surfaces? What Will Likely Happen?
While shellac can be applied over lacquer, it’s important to note that lacquer is generally more rigid and more durable.
Applying a softer finish like shellac over a harder one might not be ideal, and using lacquer over shellac is often recommended. However, personal preferences may vary.
Common Problems When Applying Shellac On Top of Lacquer
Peeling Off & Bubbling
Peeling or bubbling occurs due to the separation between lacquer and shellac layers, as the lacquer seals wood pores, hindering shellac adhesion. Lightly sanding the lacquer before applying shellac can prevent these issues.
Wrinkling & Streaking
Applying a slow-drying coat of shellac on top of the lacquer can cause wrinkling and streaking. To avoid this, use a thin coat of shellac for faster drying and reduced drying time gap between layers.
Shellac, less durable than lacquer and varnish, needs regular upkeep and is sensitive to chemicals, moisture, and scratches. Be careful when you put shellac on top of the lacquer to prevent damaging the lacquer beneath and in the top coat of shellac.
Applying Shellac on Top of Lacquer: Steps and Guide
Tools & Materials
Step #1: Thinning Shellac
Thin shellac with denatured alcohol before applying to lacquered wood for faster drying and fewer imperfections. Use a 1:4 ratio, test on scrap wood, and adjust if needed. Store in a closed container until use.
Step #2: Prepping the Surface
Place lacquer-finished items in a well-ventilated area and clean with clean rags. Good airflow aids shellac drying and avoids chemical damage.
Step #3: Sanding the Lacquer Finish
Lightly abrade lacquer finish with fine sandpaper for better adhesion. Buff gently, sand in one direction, and clean the surface afterward to improve compatibility.
Step #4: Applying Shellac
Apply shellac evenly with a clean rag or brush along the wood grain. A thin coat adheres well, dries quickly, and offers protection while covering imperfections.
Step #5: Dry it Completely
Let shellac dry completely for 30-50 minutes. Enhance ventilation for faster drying. Wait an hour before using, and apply wax if desired.
Tips for Applying Lacquer Over Shellac
Before sanding, address staples of damaged wood and remove protruding nail heads. Fill cracks with wood putty and seal wood pores with a wood filler. Sand shellac carefully before applying lacquer, then continue with refinishing as required.
Pouring Shellac on the Surface
Apply shellac with a synthetic bristle brush, using a separate container to prevent clogging. Use smooth strokes for thin coats, resulting in richer color and faster curing, enabling project completion.
Applying 1-3 Shellac Layers
Sand between each layer when applying thin coats of shellac to your woodworking project. Avoid compromising the design by adding too many layers; ideally, apply several coats (1-3), targeting two layers instead of one coat or only the topcoat.
Sanding Between Layers
Once a shellac layer is applied, wait for it to dry completely before moving to the next step. The benefit of sanding is that it eliminates imperfections, such as ridges and lumps left by the paintbrush, even if the shellac application wasn’t perfect.
Applying Lacquer Over Shellac
Apply lacquer over shellac as you would go on untreated, bare wood. Although its color tone isn’t deep, gentle smoothing unveils a richer hue, making it easier to identify application areas.
Opt for a thin layer, allowing for additional coats if needed. You can polish anything you have applied lacquer over shellac with a pumice stone or steel wool.
Do You Seal Over Lacquer?
Sealing over lacquer is feasible even if you have previously waxed shellac. Lightly sand and apply a thin sealer layer for protection, but it’s often unnecessary due to lacquer’s sealing properties. Remove and reapply if unsatisfied. An even coat will adhere properly.
Drying Time of Lacquer Before Applying Shellac
Allow the lacquer to dry for two hours to four days before putting shellac, as drying time depends on humidity  and layer thickness. Never apply shellac before the lacquer finish is fully dry.
After four days, check the surface and apply a thin shellac coat in a well-ventilated area, as shellac dries slower than lacquer, and quick drying helps prevent wrinkles on the lacquer finish.
Drying Time of Shellac Before Lacquer Application
Let shellac dry for 30 minutes to 4 hours. Before starting, remove dust from the object with a clean, soft, lint-free cloth. Be cautious, as dirty or debris-filled materials can scratch delicate items, especially furniture. This ensures a smooth finish on the surface and scratch resistance.
Best Finishes to Apply Over Lacquer
Choose the ideal shellac product for your project to minimize potential issues when applying it over lacquer. Zinsser Bulls Eye Shellac Finish is highly recommended. (Here’s a quick guide on how to apply Bulls Eye Shellac.)
White shellac is good for light woods with a light-colored lacquer finish. Orange shellac is for amber-colored woods with an amber-colored lacquer finish. You can also use dewaxed shellac as a primary finish.
When you put shellac over lacquer, it can enhance the appearance and protect your wood projects when done correctly. You can achieve a visually appealing and durable finish with careful surface preparation and using the right product.
Remember to follow the expert tips in this guide to ensure a successful process and enjoy beautiful results.
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