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Varnish

Varnish is a clear or semi-transparent coating, excluding lacquers and shellacs, formulated and recommended to provide a durable, solid, protective film on surfaces such as wood.^[1] It consists of solutions of natural or synthetic resins dissolved in organic solvents, which dry into solid, transparent films through chemical reaction or evaporation, offering varying degrees of gloss, flexibility, and durability depending on the composition.^[2] The term "varnish" derives from Old French verniz, likely from Medieval Latin veronix or Greek Berenikē (a city in ancient Cyrenaica known for resins).^[3] Varnishes have been used since antiquity for protection and enhancement of surfaces, with modern formulations including traditional oil-based, spirit, synthetic, and water-based types applied in woodworking, art, marine, and industrial contexts.^[2]

History

Early origins and traditional formulations

The origins of varnish trace back to antiquity, with evidence of resin-based coatings on ancient Egyptian artifacts dating to around 2000 BCE, where natural resins dissolved in oils or solvents were used to protect wooden and painted surfaces.^[4] Similar techniques appeared in classical Greece and Rome, employing tree resins like mastic for durable finishes on artworks and furniture. While East Asian lacquer traditions using sap from the lacquer tree (Toxicodendron vernicifluum)—known as urushi—developed independently as early as 4000 BCE and influenced later European japanning, these were distinct from Western varnish formulations.^[5]^[6] Varnish techniques evolved in Europe during the Middle Ages, where they were adapted using locally available or imported materials like amber and copal resins dissolved in linseed oil.^[7] Amber, sourced from Baltic regions and traded across the Mediterranean, was prized for its clarity and durability, while copal, introduced via early colonial exchanges, added hardness to the mixtures; these were documented in 12th-century recipes as key components for protective finishes on wood and panel paintings.^[7] This development facilitated the evolution of European varnishing practices, blending regional resources to meet demands in art, furniture, and architecture. Traditional preparation methods emphasized heating resins in drying oils to form stable emulsions, a process central to creating "boiled oil varnishes" that enhanced adhesion and gloss.^[8] Artisans would slowly heat linseed oil to high temperatures—approximately 300–350°C—while incorporating ground resins like amber or copal, stirring continuously to prevent scorching and achieve a homogeneous blend that polymerized upon cooling. This labor-intensive technique, requiring precise control to avoid degradation, produced varnishes with superior weathering resistance compared to simple oil applications. Notable examples include Venetian turpentine varnish, derived from larch resin (Larix decidua), which Italian artists mixed with oils for glazing in panel paintings to achieve luminous, enamel-like effects.^[9] Similarly, Asian urushi lacquer influenced early European formulations through imported artifacts, inspiring layered applications that combined natural saps with pigments for intricate decorative wares traded along the Silk Road.^[5] These pre-industrial recipes laid the groundwork for varnish as an essential medium in cultural preservation and artistic expression, persisting until the advent of synthetic resins in the 20th century.

Evolution to synthetic and modern varnishes

The transition from natural to synthetic varnishes accelerated in the early 20th century, driven by the need for more consistent and performant coatings amid industrial growth. A pivotal development was the introduction of fossil-fuel-derived resins, particularly alkyd resins, which combined phthalic anhydride with glycerin and fatty acids from oils to create durable, oil-modified polyesters suitable for varnishes and paints. These resins, patented by R. H. Kienle in 1927, marked a shift from variable natural sources like copal and shellac to reproducible synthetic alternatives, enabling faster production and better adhesion on industrial substrates.^[10] In the mid-20th century, further innovations expanded synthetic varnish capabilities. Polyurethane varnishes emerged in the 1950s, leveraging isocyanate-polyol reactions to form tough, flexible films with superior abrasion resistance for wood and metal applications; DuPont's commercialization during this period facilitated their widespread adoption in furniture and automotive finishes. Concurrently, acrylic emulsions, developed by Rohm & Haas in the early 1950s, introduced water-based systems that dried rapidly—often within minutes—compared to traditional oil varnishes requiring days, while offering improved clarity and removability for conservation uses. A key milestone was the advent of conversion varnishes in the 1960s, which employed acid-catalyzed curing of urea-formaldehyde or melamine resins with alkyds to achieve cross-linked, chemically resistant coatings that hardened faster and provided enhanced durability against solvents and wear.^[11]^[12]^[13] Recent advancements from 2023 to 2025 have emphasized sustainability and specialized performance, integrating bio-based resins derived from renewable sources like plant oils and lignin to replace petroleum feedstocks in varnish formulations. These bio-resins maintain mechanical strength while reducing carbon footprints, as seen in epoxy and polyester variants for wood protection that biodegrade more readily than synthetics.^[14] Nano-enhanced varnishes have gained traction for UV resistance, incorporating nanoparticles such as cerium oxide or zinc oxide into epoxy matrices to boost UV absorption by up to 785% and extend outdoor lifespan by mitigating photodegradation.^[15]

Composition

Resins

Resins serve as the primary binding agents in varnish formulations, forming the structural backbone that enables the coating to adhere to surfaces and create a protective film. These materials, derived from either natural or synthetic sources, determine key attributes such as hardness, flexibility, and resistance to environmental factors. Natural resins, which have been used for centuries, are typically exuded from plant or insect sources and processed to enhance their solubility and performance in varnishes.^[16] Natural resins are aromatic hydrocarbons that are generally soluble in alcohol or turpentine but insoluble in water, making them suitable for dissolution in varnish solvents. Copal, a prominent example, is harvested from the sap of various tropical trees such as those in the Dipterocarpaceae family and is valued for its exceptional hardness, which contributes to durable, lustrous finishes in varnishes after heat processing to improve solubility in oils. Shellac, another key natural resin, originates from the secretions of the lac insect (Kerria lacca) found on trees in India and Thailand; it exhibits strong film-forming and adhesive properties, along with solubility in ethanol, allowing it to produce clear, flexible coatings. Rosin, derived from pine tree resin through distillation of pine stumps or gum, serves as a cost-effective natural alternative in varnishes due to its tacky texture and ready solubility, though it is prone to yellowing over time from oxidation.^[16]^[17]^[18]^[19]^[20]^[21] Synthetic resins, developed in the 20th century to overcome limitations of natural variants, offer greater consistency and tailored properties for modern varnishes. Phenolic resins are thermosetting polymers produced by the condensation reaction of phenol or substituted phenols with formaldehyde under acidic or basic conditions, providing high chemical resistance and hardness in varnish films. Alkyd resins consist of polyester backbones formed by heating polyhydric alcohols with polybasic acids or their anhydrides, often modified with fatty acids for improved flexibility and adhesion in oil-based varnishes. Polyurethane resins are high-molecular-weight polymers resulting from the reaction of polyols with polyisocyanates, delivering superior durability, abrasion resistance, and elasticity to varnish coatings.^[22]^[23]^[24] In varnish, resins function as the non-volatile film-forming components, ensuring strong adhesion to substrates, cohesion within the coating, and long-term durability against wear and environmental exposure. Resins are often combined with oils to facilitate curing and enhance overall performance.^[25]

Drying oils and driers

Drying oils are essential components in traditional varnish formulations, serving as the primary film-forming agents that harden through exposure to air. These oils must contain a high proportion of polyunsaturated fatty acids, typically at least 50%, to enable the formation of a durable, cross-linked polymer network. Common examples include linseed oil, derived from flax seeds and rich in linolenic acid (up to 60% of its fatty acid content), which promotes rapid drying due to its multiple double bonds; tung oil, extracted from the nuts of the tung tree and containing high levels of eleostearic acid (approximately 80%), a conjugated triene that accelerates polymerization; and dehydrated castor oil, produced by removing water from castor oil to create conjugated double bonds, resulting in about 85% ricinoleic acid derivatives that mimic the drying properties of natural unsaturated oils.^[26]^[27]^[28] The hardening mechanism of these drying oils relies on autoxidative polymerization, a radical chain reaction initiated by atmospheric oxygen that leads to the formation of peroxides and subsequent cross-linking of the fatty acid chains into a tough, elastic film. This process begins with the abstraction of hydrogen from methylene groups adjacent to double bonds, generating free radicals that propagate through oxygen addition and eventual coupling, without relying on solvent evaporation. Non-drying oils, such as mineral oil derived from petroleum, lack sufficient unsaturation and thus remain liquid indefinitely, making them unsuitable for varnish applications where a protective, hardened coating is required. In contrast, tung oil in varnish can take up to 24 hours to reach a tack-free state per coat, influenced by its high conjugation but slower initial penetration compared to linseed.^[29]^[30]^[31]^[32]^[33] To accelerate this autoxidative process and reduce drying times, driers—typically metal salts of organic acids—are added at low concentrations, ranging from 0.01% to 0.5% by weight of the oil. Cobalt naphthenate, for instance, acts as a top drier by catalyzing radical formation at the surface through redox reactions, promoting efficient oxygen uptake and polymerization initiation. These driers work in synergy with the oils and resins, which serve as co-binders to enhance film integrity, but excessive amounts can lead to uneven drying or embrittlement.^[34]^[35]^[36]

Solvents and additives

Solvents serve as volatile carriers in varnish formulations, enabling the dissolution of resins and oils for smooth application while evaporating to leave a solid film. Common types include natural turpentine, derived from pine resin distillation, which acts as a strong solvent compatible with traditional oil-based varnishes, and petroleum-based mineral spirits, a more affordable substitute with similar solvency but differing physical properties.^[37]^[38] Evaporation rates of these solvents influence application methods; turpentine evaporates faster than mineral spirits, which evaporate more slowly and are suitable for brush application where extended working time is needed to avoid brush marks. These solvents thin the varnish mixture, facilitating even spreading and reducing viscosity for spraying or dipping, while their volatility helps prevent defects such as bubbling by allowing controlled escape during the initial drying phase.^[39] Additives are minor ingredients incorporated at low concentrations to enhance varnish performance without altering the core composition. UV absorbers, such as benzotriazoles (e.g., UV-328), protect the coating from ultraviolet degradation by absorbing harmful wavelengths, typically added at 0.5-2% by weight of the formulation to maintain clarity and color stability in exposed applications. Anti-skinning agents, often oximes like methyl ethyl ketoxime (MEKO), inhibit oxidative skin formation on the varnish surface during storage by complexing with driers, used at dosages of 0.1-0.3% based on total formulation to ensure usability without impacting film integrity. Flow modifiers, including acrylic or silicone-based rheology agents, improve leveling and reduce surface tension, preventing craters or orange peel effects, and are dosed at 0.1-1% to optimize application flow.^[40]^[41]^[42] Post-2000s environmental regulations, including the U.S. EPA's National Volatile Organic Compound Emission Standards for Architectural Coatings effective from 1999 and subsequent state-level rules, drove a shift toward low-VOC solvents in varnishes to limit emissions, replacing high-VOC options like traditional turpentine with alternatives such as oxygenated solvents or water-dispersible carriers that maintain solvency while complying with the federal limit of 450 g/L for varnishes (with some states imposing lower limits). These changes interact briefly with drying oils by providing compatible thinning without hindering oxidative polymerization.^[43]^[44]^[45]

Properties

Drying and curing processes

The drying and curing of varnish involve distinct chemical and physical transformations that convert the liquid coating into a durable solid film. The process typically progresses through three main stages: evaporation, where solvents volatilize to concentrate the resin and oils; gelation, during which the mixture transitions to a semi-solid state via initial polymerization or coalescence; and full cure, characterized by extensive cross-linking that imparts final hardness and adhesion. For oil-based varnishes, drying occurs primarily through an oxidative mechanism known as autoxidation, where atmospheric oxygen reacts with unsaturated hydrocarbon chains in the drying oils to initiate free radical formation. This begins with the abstraction of a hydrogen atom, forming hydroperoxides that decompose into radicals promoting polymerization and cross-linking:

\text{R-H + O}_2 \rightarrow \text{R-OOH} \quad \text{(leading to radicals and [polymerization](/page/Polymerization))}

The resulting network solidifies the film over time.^[29] In contrast, spirit varnishes dry via simple physical evaporation of the solvent, such as alcohol, without involving oxidation or chemical cross-linking, leaving the resin to form a brittle film upon solvent loss. Several environmental factors influence the efficiency of varnish curing. Optimal temperatures of 20-25°C promote balanced evaporation and oxidation rates, while extremes can either accelerate incomplete drying or slow the process excessively.^[46] High humidity hinders solvent evaporation and may introduce moisture into the film, delaying gelation, whereas low humidity facilitates faster drying but risks cracking.^[46] Film thickness also plays a critical role; applications of 1-2 mils per coat ensure uniform oxygen access for oxidation and prevent defects like wrinkling in thicker layers.^[47] Driers, such as metal salts, can accelerate the oxidative curing in oil varnishes by catalyzing radical formation. In practice, oil varnishes achieve dust-free dry times of 4-6 hours, allowing handling without surface contamination, but full hardness requires 7-14 days for complete cross-linking and strength development.^[48]

Physical and protective characteristics

Cured varnish films display distinct optical properties that enhance the visual quality of protected surfaces. Transparency in varnishes such as dammar and Regalrez 1094 minimizes diffuse light scattering at the varnish-substrate interface, allowing clear visibility of underlying colors, as demonstrated through optical coherence tomography (OCT) imaging, whereas Paraloid B72 exhibits significant scattering and poorer transparency.^[49] Gloss levels, measured in gloss units (GU) per ASTM D523, range from matte (<10 GU at 85°) to high gloss (>90 GU at 20°), with smoother application methods like spraying yielding higher values in formulations such as sprayed dammar (RMS roughness ~4 μm).^[49] Yellowing index, assessed via spectrophotometry (e.g., ASTM E313), increases more rapidly in natural resins like mastic compared to synthetics like Regalrez 1094, due to oxidative degradation over time.^[49] Mechanical properties of varnish films determine their durability under physical stress. Hardness, evaluated on the pencil scale (ASTM D3363), can reach 3H in polyurethane varnishes reinforced with graphene oxide, providing resistance to indentation.^[50] Flexibility is superior in high-molecular-weight synthetic resins, which form less brittle films than low-molecular-weight natural ones, reducing the risk of cracking during substrate flexing.^[49] Abrasion resistance, quantified by Taber abrader tests (ASTM D4060) using CS-10 wheels, shows minimal weight loss (e.g., <50 mg after 200 cycles) in UV-cured varnishes, indicating robust surface protection against wear.^[51] Protective characteristics enable varnishes to shield substrates from environmental damage. Water resistance is evidenced by contact angles >90° in hydrophobic formulations, such as water-based varnishes enhanced with cellulose nanofibers (up to 90.7° initial angle with stable hydrophobicity), which repel moisture and prevent ingress.^[52] UV stability improves with additives like UV absorbers or ZnO nanoparticles, reducing lignin photodegradation and yellowing in wood coatings exposed to accelerated weathering.^[53] Chemical resistance is strong in crosslinked UV-cured films, which withstand prolonged exposure to liquids like coffee without significant color change (ΔE <2 in CIELAB), resisting stains and solvents.^[54] Most varnishes have a refractive index of 1.5 to 1.6, influencing light refraction at the film-air interface (Δn ~0.5) more than at the substrate interface (Δn ~0.01), which minimally affects overall transparency.^[49] Film thickness plays a critical role in performance; thicker films (>127 μm or 5 mils) are more susceptible to cracking from internal stresses during curing, whereas optimal thicknesses (25-50 μm) balance protection and integrity.^[55]^[49]

Types

Traditional oil and spirit varnishes

Traditional oil varnishes are formulated by combining natural resins with drying oils, such as linseed or tung oil, to create a protective film that cures through oxidation and polymerization. These varnishes are classified based on the oil-to-resin ratio: long-oil varnishes contain a higher proportion of oil (typically 25-50 gallons per 100 pounds of resin), resulting in a more flexible and elastic finish suitable for outdoor applications where movement due to temperature or moisture is common.^[56] In contrast, short-oil varnishes have a lower oil content (5-11 gallons per 100 pounds of resin), producing a harder, more brittle film ideal for indoor surfaces requiring durability against wear.^[56] A representative example is spar varnish, historically developed for marine use on wooden spars; early formulations used short-oil bases with pine tar resin and boiled linseed oil, while later traditional versions incorporated tung oil for enhanced water resistance and flexibility.^[57] The preparation of traditional oil varnishes involves fusing resins into heated oils to achieve a homogeneous mixture. Resins like copal or rosin are typically melted separately, then gradually added to oils such as linseed, which are first bodied by heating to around 270-300°C to promote polymerization and remove volatiles like glycerine.^[58]^[56] The combined mixture is then cooked at temperatures between 250-300°C until no separation occurs upon cooling, ensuring chemical bonding through oxidation; this process can take several hours and requires careful control to avoid gelation or combustion.^[58]^[56] A notable application of oil varnishes appears in historical instrument making, particularly 18th-century violin varnishes inspired by makers like Stradivari, which often combined amber resin with linseed oil for acoustic clarity and aesthetic warmth. These recipes typically involved pulverizing amber, heating linseed oil to about 200-270°C with additives like lead minium for stabilization, then fusing the melted amber into the oil at high temperatures to form a durable, transparent coating.^[59]^[58] Spirit varnishes, in contrast, are quicker-drying formulations dissolved in alcohol solvents rather than oils, allowing for rapid evaporation and thin-film application without oxidation curing. They rely on natural resins such as shellac or sandarac, which dissolve readily in ethanol to form a hard, glossy surface; shellac-based spirit varnishes, derived from lac beetle secretions, are central to techniques like French polish, where multiple thin layers are rubbed onto wood for a high-luster finish on furniture or instruments.^[60] Sandarac variants, using resin from the Callitris tree, provide similar quick-drying properties but with added hardness, often mixed with alcohol or turpentine for easier brushing.^[60] Drying times for traditional oil varnishes vary with environmental conditions, but they typically become tack-free in 24-48 hours at moderate temperatures (around 20-25°C), allowing recoating after light sanding, though full hardness may take several days due to the slow oxidative curing process.^[61]^[62]

Synthetic and polymer-based varnishes

Synthetic and polymer-based varnishes utilize man-made polymers to create durable, high-performance coatings that surpass the slower-drying characteristics of traditional oil-based precursors. These varnishes form through chemical crosslinking or polymerization, enabling rapid curing and enhanced resistance to wear, chemicals, and environmental factors in industrial applications such as furniture, automotive, and protective finishes.^[63] Polyurethane varnishes are divided into one-part moisture-cure systems and two-part isocyanate-based systems. One-part varnishes cure by reacting with atmospheric moisture, offering ease of use without mixing and suitability for field applications.^[64] Two-part systems combine a polyol resin with a polyisocyanate hardener, such as hexamethylene diisocyanate or isophorone diisocyanate, to form a thermoset polymer with high crosslink density.^[63] Both variants provide high abrasion resistance, with certain advanced poly(hydroxyurethane) formulations, such as those with nanofillers, exceeding 350 double rubs in methanol ketone tests.^[65] Alkyd and acrylic varnishes are frequently modified with styrene to achieve faster drying via accelerated polymerization. Styrene-modified alkyd resins, like those with low viscosity and excellent pigment wetting, support quick-drying enamels and hammer finishes in industrial settings.^[66] Acrylic variants contribute to rapid total drying by solvent evaporation, enhancing productivity in coating processes.^[67] Lacquer types, such as nitrocellulose dissolved in organic solvents and combined with oil-modified alkyds, offer fast evaporation and easy sanding for wood surfaces.^[68] Epoxy varnishes employ two-component systems where a bisphenol A-based epoxy resin is cured with polyamine hardeners, such as aliphatic polyamines, to produce a dense crosslinked structure. This curing mechanism, often at ambient or elevated temperatures, imparts excellent chemical resistance, particularly to acids and solvents, by limiting diffusion through the polymer matrix.^[69] Polyamine-hardened epoxies maintain gloss and color retention while providing robust protection in corrosive environments.^[70] Conversion varnishes, developed in the 1960s, incorporate urea-formaldehyde resins as crosslinkers in solvent-based formulations for cabinetry and furniture finishing. These post-catalyzed systems deliver high clarity, durability, and moisture resistance, with typical VOC contents ranging from 300 to 500 g/L to comply with industrial emission standards.^[71]^[72]

Water-based and eco-friendly varnishes

Water-based varnishes utilize emulsions of acrylic and polyurethane dispersions as primary binders, enabling film formation through coalescence drying where water evaporates and particles merge without relying on organic solvents.^[73] This process involves colloidal dispersions of polymer particles that interdiffuse upon water loss, creating a continuous protective layer suitable for wood and other substrates.^[74] Polyurethane dispersions (PUDs), in particular, provide enhanced flexibility and adhesion in waterborne systems with minimal solvent content. Bio-based varnishes incorporate resins derived from soy or other plant oils, offering sustainable alternatives with significant renewable content. For instance, formulations using epoxidized soybean oil (ESO) as a base resin achieve improved mechanical properties while maintaining high biobased carbon levels, often exceeding 80% in optimized blends.^[75] These resins, acrylated from vegetable oils, enable solvent-free wood coatings with enhanced performance, including better hardness and gloss retention.^[76] Recent developments, such as those certified for soybean oil-derived content, support UV-curable applications with verified bio-based percentages.^[77] UV-curable varnishes rely on acrylate oligomers, such as urethane acrylates, which polymerize rapidly under ultraviolet light exposure to form durable films. Typical curing requires energy doses around 1,000 mJ/cm² in the UV-A range, ensuring efficient cross-linking for applications like wood finishing.^[78] This photopolymerization process minimizes drying times and emissions compared to traditional methods.^[79] These eco-friendly varnishes adhere to stringent low-VOC standards, with EU regulations under the Decopaint Directive limiting solvent-borne wood varnishes to 400 g/L, water-borne to 130 g/L, and solvent-borne clear coats to 300 g/L (phase II, as of 2010), to reduce environmental emissions.^[80] Innovations in nano-coatings further enhance self-cleaning properties, incorporating nanomaterials like silica nanoparticles into varnish formulations for superhydrophobic surfaces that repel water and dirt on wood substrates.^[81] Recent advancements from 2024 reviews highlight nanotechnology's role in wood preservation, enabling durable, low-maintenance finishes resistant to weathering.^[82]

Applications

Wood and furniture finishing

Varnish is widely used to protect and beautify wooden surfaces in furniture and interior woodwork, forming a durable, transparent film that shields against wear while highlighting the wood's natural beauty. This finish enhances the grain patterns, providing a warm, lustrous appearance that elevates the aesthetic appeal of tabletops, cabinets, and chair frames. In addition to aesthetic enhancement, varnish offers practical benefits such as improved scratch resistance, making it suitable for everyday furniture subjected to light impacts and abrasions.^[83]^[62] Application techniques for varnish on wood furniture typically involve multiple thin layers to achieve an even, professional result. Brushing is a common method, using natural-bristle brushes for oil-based varnishes to apply 3-5 coats, starting with a thinned first coat to ensure penetration and adhesion. Spraying provides a smoother finish for larger pieces, allowing for even coverage without brush marks, though it requires proper equipment and ventilation. Between coats, light sanding with 220-320 grit sandpaper removes imperfections and promotes adhesion, followed by wiping away dust to prevent contamination.^[84]^[85]^[86] The choice of varnish type depends on the desired aesthetic and durability needs. Oil-based varnishes, such as those made with tung or linseed oil, impart warm, amber tones that complement traditional or rustic furniture styles, enhancing depth in woods like oak or mahogany. In contrast, polyurethane varnishes, particularly water-based variants, are preferred for high-traffic furniture like dining tables due to their superior hardness and clarity, offering robust protection without yellowing over time.^[87]^[88] Key benefits include enhanced scratch resistance from the built-up film, which can total 4-6 mils in dry film thickness for adequate protection without cracking. Varnish also excels in grain enhancement, allowing the wood's texture to remain visible while adding a subtle sheen. In antique restoration, oil varnishes are often selected to replicate historical finishes, preserving the piece's patina and value. Varnish is highly compatible with wood stains, applied as a topcoat after staining to seal in color and prevent fading, ensuring long-lasting vibrancy on furniture surfaces.^[89]^[90]^[91]

Marine and outdoor protection

Spar varnish is a specialized type of varnish formulated for marine and outdoor applications, offering flexibility and durability against harsh environmental conditions such as saltwater exposure and intense UV radiation.^[92] It typically incorporates phenolic resins in its base, which contribute to its UV resistance, often enhanced by multiple UV blockers or inhibitors to prevent degradation from sunlight.^[93] This composition allows the varnish to remain elastic, accommodating wood expansion and contraction without cracking, and provides a protective barrier against moisture and salt.^[94] In marine settings, spar varnish is commonly applied to teak decks and railings on boats, where it seals the wood to maintain its appearance and structural integrity above the waterline. Due to ongoing exposure to sun, spray, and weather, reapplication is generally required every 1 to 3 years, depending on usage and environmental severity, to restore protection and gloss.^[95] Key challenges in these applications include resisting saltwater corrosion, which can accelerate wood deterioration if the coating fails, and providing flexibility to handle flexing from temperature fluctuations and wave motion without developing cracks.^[96] Many formulations use a tung oil base to enhance elasticity, allowing the finish to stretch and recover while repelling water and salt.^[93] For military and high-stakes marine uses, spar varnishes often meet standards like MIL-V-1174, which specifies water-resisting properties for spar varnish in demanding conditions.^[97]

Specialized uses in instruments and art

In the construction of stringed musical instruments like violins, varnish serves both protective and acoustic functions, with thin layers of cooked oil-resin formulations applied to enhance tonal qualities. Traditional violin varnishes typically consist of vegetable oils such as linseed or walnut oil combined with resins like copal, heated together to form a flexible, transparent coating that allows wood vibrations to propagate effectively.^[98]^[99] Historical recipes, such as those using copal resin dissolved in turpentine and mixed with linseed oil, exemplify early approaches aimed at achieving durability and subtle color without dampening sound.^[100] These oil-based varnishes, applied in layers approximately 0.1 mm thick after wear, contribute to the instrument's resonance by influencing how the wood absorbs and transmits impulses.^[101]^[102] Myths surrounding the varnish on Antonio Stradivari's instruments, often romanticized as containing rare ingredients like ambergris or secret alchemical compounds, have been debunked by scientific analyses revealing ordinary mixtures of common oils, pigments, and resins. Studies using techniques like gas chromatography-mass spectrometry confirm that Stradivari's coatings were not uniquely formulated for superior tone but rather standard for the era, with the instrument's acoustic excellence stemming more from wood selection and construction.^[103]^[104] In art conservation, picture varnishes protect paintings from environmental damage while unifying surface appearance, with synthetic resins like Paraloid B-72 preferred for their removability and stability. This ethyl methacrylate/methyl acrylate copolymer forms a clear, non-yellowing film that can be dissolved in solvents like acetone for future cleaning, ensuring the varnish does not permanently alter the artwork's optical properties.^[105] Key requirements include reversibility to allow periodic removal of accumulated dirt and non-yellowing to prevent discoloration over time, enabling conservators to maintain the original colors and textures.^[106] Application often involves spraying to achieve even coverage without brush marks, minimizing optical distortion on delicate surfaces.^[107] Recent updates to ISO standards, such as ISO 15528:2020 on sampling procedures for paints and varnishes, support standardized testing for conservation materials, ensuring picture varnishes meet criteria for removability and aging resistance in heritage applications.^[108]

Safety and environmental aspects

Health and handling hazards

Varnish products, particularly solvent-based formulations, contain volatile organic compounds (VOCs) such as toluene and xylene, which pose significant inhalation risks during application and drying. Inhalation of toluene vapors can lead to irritated eyes, nose, and throat, as well as headaches and dizziness, with effects worsening at concentrations approaching or exceeding the NIOSH recommended exposure limit of 100 ppm over a 10-hour period. Similarly, xylene exposure may cause central nervous system depression and respiratory irritation at levels above the OSHA permissible exposure limit (PEL) of 100 ppm as an 8-hour time-weighted average. In polyurethane varnishes, isocyanates contribute to skin irritation upon contact, manifesting as redness, itching, or dermatitis. Flammability is a primary hazard associated with solvent-based varnishes, which typically have low flash points, such as approximately 25°C for many formulations, making them highly susceptible to ignition from sparks, open flames, or hot surfaces. These vapors can form explosive mixtures in air, particularly in confined or poorly ventilated spaces, where concentrations within the flammable range (often 1-7% by volume) increase the risk of fire or explosion during handling or application. Proper storage in approved flammable liquid cabinets and avoidance of ignition sources are essential to mitigate these dangers. Acute effects from varnish exposure include severe eye irritation or damage upon direct contact, leading to redness, tearing, and potential corneal injury, while skin contact can result in immediate irritation, burns, or allergic reactions depending on the formulation. Chronic exposure, especially to isocyanates in polyurethane-based varnishes, may induce respiratory sensitization, increasing susceptibility to asthma-like symptoms such as wheezing, shortness of breath, and bronchial hyperreactivity even at low levels over time. Occupational safety standards mandate specific exposure limits, such as the OSHA PEL of 100 ppm for xylene and 200 ppm for toluene, to prevent adverse health outcomes during varnish use. Personal protective equipment (PPE) requirements include chemical-resistant gloves to prevent skin absorption, safety goggles or face shields for eye protection, and NIOSH-approved respirators (e.g., with organic vapor cartridges) when ventilation is inadequate to maintain exposures below PELs. These measures align with broader environmental regulations aimed at controlling workplace hazards from volatile chemicals.

Sustainability and regulatory compliance

Varnishes, particularly solvent-based formulations, contribute to environmental degradation through the emission of volatile organic compounds (VOCs), which react with nitrogen oxides in sunlight to form ground-level ozone and smog, exacerbating air pollution.^[109]^[110] These emissions occur during application and curing, with traditional oil and spirit varnishes releasing higher levels compared to modern alternatives. Additionally, heavy metals such as cobalt, used as driers in alkyd-based varnishes to accelerate oxidation, pose ecological risks due to their toxicity and persistence; due to the classification of certain cobalt compounds as carcinogenic and reprotoxic under EU REACH, along with ongoing regulatory pressures such as proposed occupational exposure limits in 2025, the coatings industry is transitioning from cobalt driers to alternatives like manganese and iron carboxylates, with new EU occupational exposure limits set at 0.01 mg/m³ for inhalable cobalt and 0.0025 mg/m³ for respirable cobalt as of 2025.^[111]^[112]^[113]^[114] Regulatory frameworks worldwide aim to mitigate these impacts by capping VOC content and promoting low-emission products. In the United States, the Environmental Protection Agency (EPA) enforces the National Volatile Organic Compound Emission Standards for Architectural Coatings under 40 CFR Part 59, setting category-specific limits such as 250 grams per liter (g/L) for industrial maintenance coatings and lower thresholds like 50 g/L for flat interior paints to reduce atmospheric contributions to smog formation.^[43] In the European Union, the Ecolabel scheme certifies paints and varnishes with stringent VOC emission limits, including total VOC (TVOC) thresholds below 300 micrograms per cubic meter after 28 days, alongside restrictions on hazardous substances to ensure minimal environmental release.^[115] These standards, updated in 2024-2025, also incorporate carbon footprint assessments for production processes.^[116] Sustainable practices in the varnish sector include recycling initiatives to divert waste from landfills and reduce resource consumption. Programs such as those managed by PaintCare in the US facilitate the collection and recycling of unused paints and varnishes, processing them into recycled paint products or fuel, thereby conserving raw materials and minimizing environmental disposal impacts.^[117] Similarly, solvent recovery systems for mineral spirits used in varnish thinning enable reuse, cutting down on volatile emissions and hazardous waste generation.^[118] Bio-degradable and water-based alternatives are gaining traction, driven by 2025 environmental mandates in regions like the EU, which prioritize formulations with reduced solvent content to comply with updated Ecolabel criteria and broader decarbonization goals.^[119] The global varnish market is shifting toward zero-VOC and low-VOC products, reflecting regulatory pressures and consumer demand for eco-friendly options; for instance, the low-VOC paints segment, which includes varnishes, is projected to grow from USD 9.34 billion in 2025 to USD 12.26 billion by 2030 at a compound annual growth rate (CAGR) exceeding 5.6%, indicating a substantial market transition.^[120] Production of varnishes contributes to carbon footprints primarily through energy-intensive manufacturing and raw material sourcing, with life-cycle assessments showing emissions ranging from 1-5 kg CO2 equivalent per liter depending on formulation, prompting innovations like bio-based resins to lower impacts.^[121]^[122]

References

[1]
40 CFR 59.401 -- Definitions. - eCFR
Varnish means a clear or semi-transparent coating, excluding lacquers and shellacs, formulated and recommended to provide a durable, solid, protective film.
[2]
Painting Varnishes | Museum Conservation Institute
By the early Renaissance, a variety of materials had been developed for use as painting varnishes, ranging from egg white to resin. Tree resins (mastic and ...
[3]
Read an Excerpt from “The Varnish and the Glaze” by Marjolijn Bol
Mar 17, 2023 · For more than a century after his death, the fifteenth-century painter Jan van Eyck was widely credited with inventing varnish and oil paint.
[4]
[PDF] Varnishes - Sacramento State
Varnishes contain varying combinations of resins that provide strength, body, and gloss, which are dissolved in drying oils such as tung, linseed, or an alkyd.
[5]
Stradivari's Varnish Revisited: Feature Improvements Using ... - NIH
Sep 4, 2023 · Different investigations carried out over the past few decades suggested that linseed oil and colophony (or equivalent compounds) were the main ...
[6]
[PDF] Determination of oil and resin in varnish
litharge, manganese borate, and benzine. turpentine, and Damar varnish. , and turpentine. , and turpentine.
[7]
[PDF] The Conservation of Asian Lacquer
It has been used since ancient times and continues to be made today. The earliest lacquers identified thus far were produced in China around  BCE.
[8]
[PDF] Urushi - Getty Museum
The craft of lacquerware has an age-old history in China. Records in ancient books and documents and findings from archaeological excavations confirm.
[9]
Lacquer - MediaWiki - Conservation Wiki
Jan 21, 2025 · The use of lacquer as a protective finish and decorative art was developed in China, and lacquered wooden objects dating to Neolithic period ...Missing: ancient | Show results with:ancient
[10]
Oil varnish - MFA Cameo - Museum of Fine Arts Boston
Oct 2, 2022 · Some early resin-oil varnish recipes in the 12th century contained a resin, such as Sandarac, Amber, or Copal, dissolved in a boiled linseed oil ...Missing: introduction Europe trade routes
[11]
16th Century Amber Varnish
Historically, resins were utilized in one of two ways; either as a resin dissolved into boiling hot oil, like Linseed oil, to make an oil varnish (like amber ...
[12]
The devil is in the details: turpentine varnish - The Recipes Project
Jun 5, 2018 · Venice turpentine is a thick, viscous exudation from the Austrian larch tree, which is not used as a varnish on its own as it becomes dark and ...
[13]
An Overview of Alkyd Resins - Corrosionpedia
Feb 13, 2020 · These oil-modified polyester resins were well suited for use as binders in paints. Kienle applied for a U.S. patent on January 29, 1927 ...
[14]
Introduction to Polyurethane Chemistry - ACS Publications
May 19, 2021 · In 1937, it reached industrial-scale synthesis and it was established in the market in the 1950s. Polyurethanes are characterized by the ...
[15]
[PDF] House Paints, 1900–1960 - Getty Museum
Work into the development of synthetic resins began in the mid- ... years also significantly affected the development of alkyd resins. Before.
[16]
Catalyzed Finishes | Popular Woodworking
Nov 17, 2022 · To initiate the crosslinking of the amino and alkyd resins, you have to add the acid catalyst to catalyzed (“conversion”) varnish and post- ...Missing: 1960s | Show results with:1960s
[17]
Recent Advances in Bio-Based Wood Protective Systems - MDPI
This review emphasizes the recent ongoing shift in the wood coating industry towards bio-based resources and circular economy principles, ...
[18]
Enhanced ultraviolet aging resistance of epoxy resins through ...
Jul 7, 2024 · A 785% increase in the UV absorption capacity was achieved in the MEP compared with that in the pristine epoxy resin. After 300 h of UV exposure ...Missing: varnishes | Show results with:varnishes
[19]
Natural resin - CAMEO
Oct 17, 2024 · Natural resins are aromatic hydrocarbons that are generally soluble in alcohol or turpentine and insoluble in water.
[20]
[PDF] Copal Resin - Kremer Pigmente
The principal virtue of copal resin is its hardness, on account of which copal varnish dries with a good hard surface, ... soluble in linseed oil and turpentine ...
[21]
Shellac-based materials: Structures, properties, and applications
Aug 27, 2024 · Shellac stands out among natural polymers as the sole animal-derived resin, boasting a complex polyester composition comprising polyhydroxy long ...
[22]
Shellac-based materials: Structures, properties, and applications
Its unique attributes include biocompatibility, non-toxicity, distinctive amphiphilicity, superb film-forming and adhesive properties, excellent dielectric ...
[23]
OCCUPATIONAL EXPOSURES IN PAINT MANUFACTURE ... - NCBI
Varnish is defined as a homogeneous, transparent or translucent liquid that is converted to a solid, transparent film after being applied as a thin layer ...
[24]
CBD-78. Paints and Other Coatings - NRC-IRC - MIT
Rosin itself causes yellowing, however, and today it is used in manufacturing synthetic resins that have better colour retention. Other natural resins were ...
[25]
Phenolic Resin - an overview | ScienceDirect Topics
The phenolic resins contain basically p-t-amylphenol, p-t-butylphenol, p-nonylphenol, mixed cresols, and also used cashew nutshell liquid (Fig. 6.23). The ...
[26]
Types of Synthetic Resins | Applications and Their Uses
Dec 30, 2019 · Alkyd resins are polyester thermoplastic resins made with polybasic acids or their anhydrides by heating polyhydric alcohols. These are used to ...Missing: composition | Show results with:composition
[27]
Guide! Different Types of Resin - YIHEDA - YHDFA
Jul 5, 2024 · Polyurethane resins are high molecular compounds formed by the polymerization of polyols and polyisocyanates, offering many characteristics: 1.Missing: composition | Show results with:composition
[28]
Adhesion in Paint and Coatings: Theories, Types & Test Methods
Jul 14, 2025 · Note: The binder or resin in paint formulation is the non-volatile film-forming component. It ensures adhesion to the substrate and cohesion ...
[29]
Drying Oil - an overview | ScienceDirect Topics
Drying oils are natural binders that contain a minimum of 50% polyunsaturated fatty acids, such as linolenic acid, and are used to form alkyd resins through ...
[30]
Drying Oils and Related Products - ResearchGate
Drying oils are those which contain enough unsaturated fatty acids that can undergo oxidative polymerization reactions that result in a hardened oil film.
[31]
[PDF] dehydrated castor oil dco - Traquisa
Fatty acids composition (%). Palmitic acid. 1 – 3. Stearic acid. 1 – 3. C18: 1 ... drying oil. Properties. DCO does not have Linolenic acid in their.
[32]
Comprehensive Characterization of Drying Oil Oxidation and ...
Aug 27, 2024 · Drying oil autoxidation consumes oxygen as part of the propagation step for polymer network formation. (1) It is virtually impossible to compose ...
[33]
On the drying behavior of natural oils used for solid wood finishing
Radical chain reactions during the autoxidative drying of oils result in a crosslinked polymer network. During the corresponding transition from the liquid oil ...
[34]
Microscale mechanochemical characterization of drying oil films by ...
Jun 29, 2022 · The hardening of drying oils is a chemical transformation, which occurs via an autoxidative process followed by polymerization (2, 3). Despite ...
[35]
https://www.chimia.ch/chimia/article/download/2002_184/2869/13554
[36]
How To Pick Tung Oil Finishes - This Old House
A few hours to a day to dry between coats and 1–7 days to fully cure. A few hours to dry between coats and up to 24 hours to fully cure. Environmental ...
[37]
Types of driers & their functions - Goldstab Organics
Cobalt: Cobalt is the most important and most widely used drier metal of all. It is primarily an oxidation catalyst and as such acts as a surface drier.
[38]
[PDF] Driers - CHIMIA
The most important catalysts known and in use as driers for the drying of paint are transition metal-based driers, such as cobalt octoate. In conventional ...
[39]
Review of autoxidation and driers - ScienceDirect.com
The order of efficiency for the three most frequently used driers is Co > Mn > Pb [14], [15]. Both cobalt and manganese can easily dry the surface of a produced ...Missing: naphthenate | Show results with:naphthenate
[40]
[PDF] Determination of volatile thinner in oil varnish.
I. INTRODUCTION. Almost all oil varnishes * contain, as thinner, gum spirits of turpentine, "mineral spirits," 2 or a mixture of the two. Most of the ...
[41]
[PDF] Volatile paint and varnish thinners - GovInfo
Mineral spirits is not as good a solvent as turpentine, but can be used in many cases. The only marked difference between products containing a petroleum ...Missing: rates | Show results with:rates
[42]
Technical Exchange--WN Jan 1995
... evaporation time of 5140 seconds to 90% evaporation and in mineral spirits with evaporation rates between 3200-4600 seconds to 90% evaporation[3]. I have ...
[43]
UV-328 | C22H29N3O | CID 33263 - PubChem
Used as a UV absorber in plastics applications. Particularly recommended for polyolefins, polyurethanes, PVC, polyacrylate, epoxy, and elastomers. Offers strong ...<|separator|>
[44]
EP1103583A1 - Anti-skinning agents - Google Patents
Typically, the anti-skinning agent will be used in an amount between 0.1 and 5 wt.%, preferably up to 2 wt.%, based on the weight of the composition. The ...
[45]
[PDF] Borchers GmbH
Feb 23, 2017 · All recommended dosages in this guide are calculated based on total formulation. 4b) Other Options. - Try combinations of anti- skinning agents.Missing: varnish | Show results with:varnish
[46]
40 CFR Part 59 Subpart D -- National Volatile Organic Compound ...
(1) The total amount of VOC contained in all the coatings selected for exemption must be equal to or less than 23 megagrams (25 tons) for the period of time ...
[47]
[PDF] Federal Register/Vol. 65, No. 203/Thursday, October 19, 2000/Rules ...
Oct 19, 2000 · For the ''outdoor, harsh exposure, or extreme performance'' coatings, EPA recommended a RACT limit of 3.5 pounds of VOC per gallon of coating, ...
[48]
Paint Drying and Curing: A Journey to Flawless Finish - SpecialChem
Jul 14, 2025 · Which factors affect the drying and curing time? · I. Mastering temperature control · II. Humidity: The key to optimal paint drying and curing.
[49]
Applying Varnish
Applying one fluid ounce (about 30milliliters) over 6-8 square feet will give a wet film thickness of 2-3 mils. Much thicker films may not dry and cure well.
[50]
Applying Varnish Paint And Drying Guide - Coatings Directory
May 2, 2025 · Full Cure: 7-30 days, the molecular chains are completely cross-linked and reach the ultimate hardness. Ambient temperature and humidity play a ...
[51]
[PDF] Optical and material properties of varnishes for paintings Samuel J ...
“The effects of solution application on some mechanical and physical properties ... the mechanical and surface properties of oil paint films treated with organic ...
[52]
(PDF) Mechanical and Chemical Resistance of UV Coating Systems ...
Nov 12, 2023 · A key feature of varnish coatings on furniture surfaces is their optical properties, which often determine customers' purchase choices.
[53]
https://bioresources.cnr.ncsu.edu/wp-content/uploads/2025/03/BioRes_20_2_Hubbe_Laleicke_Review_Chem_Mechanistic_Aspects_Wood_Finishing_24465.pdf
[54]
[PDF] Chemical and Mechanistic Aspects of Wood Finishing: A Review ...
Mar 27, 2025 · This review article considers the formulation of a broad range of coatings designed for the protection and changing the appearance of wood.
[55]
Mechanical and Chemical Resistance of UV Coating Systems ...
The resistance decreased by 23 N when the varnish application was increased to 45 g/m2. A further increase to 50 g/m2 resulted in a decrease of 107 N.
[56]
Dry Film Thickness Measurement - Wood Substrates - DeFelsko
For example, conversion varnishes are harder than other coatings and should not be used in excess of 5 mils dry thickness in order to prevent cracking or other ...
[57]
[PDF] Circular of the Bureau of Standards no. 69: paint and varnish
various ways, being then called “ varnish oil,” “borate oil,” 19 etc. Tung oil when heated at 250-300° C polymerizes with the forma- tion of a jelly-like ...
[58]
A Guide to the Different Types of Varnish - Sail Magazine
Apr 12, 2016 · Long oil varnishes became more durable, especially when combined with tung oil (or China wood oil), but they were more expensive. There are ...
[59]
What I learned making historic varnishes - Australian Wood Review
May 7, 2025 · The author recreates varnishes on his balcony. Heating linseed oil and resins to high temperatures is not recommended as there are risks of fire and vapour ...
[60]
Experiments with Amber: Recreating an Early Modern Varnish Recipe on the History of Design Course • V&A Blog
### Summary of Historical Violin/Instrument Varnish Recipes Involving Amber and Linseed Oil (18th Century, e.g., Stradivari)
[61]
French Polish
There 2 types of varnish;. spirit varnish, made by dissolving natural resins like sandarac, mastic and shellac, in alcohol or turpentine to facilitate ...
[62]
[PDF] High-Build Varnish - Pettit Paint
DRY TIME (HOURS):. Set-to-touch Tack Free Dry Hard. 90°. 1-3 hrs. 4-6 hrs 8-12 hrs. 70°. 3-4 hrs. 6-8 hrs 16-20 hrs. 50°. 4-8 hrs 12-16 hrs 24-48 hrs ... oil ...
[63]
Top 10 Essential Wood Finishes: Pros, Cons, and Application Tips
Application tips: Apply linseed oil with a clean, lint-free cloth, working in thin, even coats. Allow each coat to dry for 24–48 hours before applying ...
[64]
Polyurethane coatings: A brief overview - ResearchGate
Aug 10, 2025 · However, isocyanate, which is a key monomer for conventional PU, has some drawbacks such as high toxicity and sensitivity to moisture.
[65]
[PDF] =-AIRRESOURCES BOARD
Acrylic baking enamels. Sarne as above. Moisture cured, pigmented, single component polyurethanes. This technology is still in the process of being developed.
[66]
Poly(hydroxyurethane) Adhesives and Coatings: State-of-the-Art ...
Polyurethane (PU) adhesives and coatings are widely used to fabricate high-quality materials due to their excellent properties and their versatile nature.
[67]
VIALKYD® AV 384/70X - Allnex
VIALKYD® AV 384/70X is a styrene modified alkyd resin that has low viscosity, excellent pigment wetting and is quick drying.
[68]
What Does Synthetic, Acrylic and Alkyd Paint Really Mean?
Jun 12, 2024 · PROPERTIES OF ACRYLIC PAINTS. -Fast total drying time. -The great advantage is that it dries naturally: it only dries by solvent evaporation ...
[69]
Coating compositions comprising an oil modified alkyd resin and ...
The principal objective of this invention is to improve the outdoor durability of pigmented nitrocellulose/oilmodified alkyd resin lacquers without sacrificing ...Missing: faster | Show results with:faster
[70]
Chemical-resistance values of epoxy resins hardened with polyamines
Aug 7, 2025 · The chemical resistance of epoxy resins is affected by the molecular weight and type of epoxy resin, the polyamine functionality, the polyamine ...Missing: varnishes | Show results with:varnishes
[71]
Polyamine Epoxy Coating - CTech-LLC
Rating 5.0 (1) PEC™ is a two component polyamine cured epoxy coating which has excellent gloss, color retention, good chemical and solvent resistance.
[72]
Ultra® Clear Conversion Varnish 550 VOC M615-29107 - Mohawk
This post-catalyzed varnish offers high-end finish, durability, moisture resistance, good color retention, UV inhibitor, and is VOC compliant with high solids.Missing: urea- formaldehyde 1960s synthetic 300-500 g/ L
[73]
VOCs in cabinetry conversion varnish - GreenBuildingAdvisor
Apr 12, 2017 · Rudd conversion varnish has a VOC level of ~500 g/L, while the U.S. maximum allowable is 725 g/L. Benjamin Moore and Sherwin Williams have ...Missing: urea- 1960s synthetic 300-500
[74]
[PDF] Drying, Film Formation and Open Time of Aqueous Polymer ...
Generally, water-based paints and varnishes are colloidal dispersions that consist of the dispersion medium (= water), of binders, surfactants, organic co ...
[75]
[PDF] Designing Multicomponent Polymer Colloids for Self-Stratifying Films
Sep 2, 2022 · As water evaporates, the colloidal particles (shells) come into contact and coalesce via interdiffusion to form a continuous matrix embedding ...
[76]
Evaluation and Improvement of Bio-Based Sustainable Resin ... - NIH
Oct 29, 2023 · The bio-resin film was formulated using the improved epoxidized soybean oils—from ESO (10:2.5) to ESO (10:10)—and equal amounts of acrylic acid.
[77]
(PDF) Tailored Biobased Resins from Acrylated Vegetable Oils for ...
Mar 15, 2023 · Herein, we propose the preparation of resins from biobased components to produce functional and solvent‐free wood coatings with enhanced ...
[78]
[PDF] UV resins made with bio-based content - Covestro Solution Center
The bio-based content used in our UV resins comes from natural sources such as soybean oil, which is backed up by certified external analysis. Specifically, the ...
[79]
Inherently Reactive Urethane Acrylate Resins - UV+EB Technology
Feb 26, 2025 · ... typical UV-A dose of ca. 1,000 mJ/cm2 and a typical UV-B dose of 1,200 mJ/cm2. The front side of the film is defined here as the side ...
[80]
Study on Press Formability and Properties of UV-Curable ...
Feb 10, 2023 · Schematic process of UV curing coatings for pre-coated metals. Acrylate oligomers are linear molecules containing two double bonds. Their ...Missing: cm² | Show results with:cm²<|separator|>
[81]
[PDF] B C1 DIRECTIVE 2004/42/EC OF THE EUROPEAN ... - EUR-Lex
Jul 16, 2021 · 1. The purpose of this Directive is to limit the total content of VOCs in certain paints and varnishes and vehicle refinishing products in order.
[82]
Nature-Inspired Superhydrophobic Coating Materials - NIH
This self-cleaning ability is attributed to the surface's microstructures and nanostructures, which form a unique morphology. Upon contact with water droplets, ...Missing: varnishes | Show results with:varnishes
[83]
Advances in wood preservation technology: A review of ...
This review paper explores and summarises the wood preservation technologies and techniques from 2019 to 2024, including nanotechnology and SEDDS applications ...
[84]
What is Varnish? - This Old House
The clear finish allows the natural grain and color of the wood to shine through, creating a lustrous look that many homeowners and woodworkers prefer.
[85]
https://home.howstuffworks.com/home-improvement/home-diy/projects/how-to-refinish-furniture12.htm
[86]
How to Varnish Furniture - Home and Garden - HowStuffWorks
Apply varnish first along the grain of the wood, flowing it on in even strips. Then apply more varnish across the grain to level and even the surface.
[87]
https://www.thespruce.com/water-based-polyurethane-wood-finishes-5101497
[88]
Water-Based vs. Oil-Based Polyurethane Comparison Guide
May 27, 2025 · Water-based polyurethane tends to be less durable than oil-based products. Water-based polyurethane scratches and dents easily.
[89]
https://woodweb.com/knowledge_base/Measuring_and_Calculating_Mil_Thickness.html
[90]
Measuring and Calculating Mil Thickness of Finish Coats - Woodweb
Typically for most lacquers and conversion varnishes, the product data sheets will recommend applying wet coats in the area of 3 to 5mil and they will recommend ...
[91]
Finish Compatibility - Popular Woodworking
Mar 23, 2021 · Almost any finishing product – stain, filler, glaze, finish – can be applied successfully over any other finishing product, except wax ( ...
[92]
Historic Antique Furniture Finishes: Shellac, Varnish & Wax Explained
Aug 15, 2025 · The trade-off is that it is softer and less scratch-resistant than other finishes.
[93]
Marine Varnish
### Summary of Spar Varnish Information
[94]
TotalBoat Gleam Marine Spar Varnish
In stock Rating 4.5 (215) TotalBoat Gleam Marine Spar Varnish features a premium tung oil formula, with a phenolic resin base and added UV inhibitors.Missing: composition | Show results with:composition
[95]
https://www.bottompaintstore.com/blog/marine-varnish/marine-varnish-choose-apply-maintain-long-lasting-protection/
[96]
https://www.dcms.uscg.mil/Portals/10/CG-4/documents/SFLC/StandardSpec2020/SFLC-Std-Spec-6310-%282020%29.pdf
[97]
[PDF] SFLC-Std-Spec-6310-(2020).pdf - Coast Guard
This Standard Specification describes requirements applicable to preservation of Coast Guard ship structures. 1.2 Appendices. PROCESS STANDARD. APPENDIX. Cutter ...
[98]
MIL-V-1174 Varnish, Spar, Water Resisting (Formula No 80)
In stockShop MIL-V-1174 spar varnish, a water-resistant formula for military specifications. Browse high-quality paints, coatings, and varnishes at Chemsol.Missing: marine | Show results with:marine
[99]
The components of violin varnish | Focus - The Strad
Oct 12, 2021 · Violin varnish is made from tree sap and vegetable oil, usually walnut or linseed oil, cooked together. Linseed oil provides flexibility.Missing: tone enhancement copal
[100]
[PDF] A close look into the history and chemistry of varnish making can ...
This ancient varnish, made with five or six parts oil to one part resin, and without a cooked-in solvent, would have been warmed and then applied to the cases ...
[101]
https://maestronet.com/forum/index.php?/topic/334394-varnish-how-much-is-too-much/
[102]
Varnish: How much is too much? - The Pegbox - Maestronet Forums
Mar 29, 2016 · The varnish layer was about 0.1 mm assuming a rib thickness of 1mm. But with 300 years of polishing, most of them are worn down to just a thin ...varnish thickness - The Pegbox - Maestronet Forums"Right" amount of varnish on a violin - The Pegbox - MaestronetMore results from maestronet.comMissing: 0.1-0.2 | Show results with:0.1-0.2
[103]
Violin varnish: Key to a fiddle's tone - EurekAlert!
Mar 8, 2016 · Varnish does more than just provide a protective sheen to a violin. It influences the vibrations and impulses that the wood absorbs and therefore the quality ...Missing: yellowing reversible
[104]
Stradivari's Secret - C&EN - American Chemical Society
Dec 8, 2009 · The largest Stradivari study to date finds that the varnish used by the instrument maker was composed of widely available mundane oils, pigments, and resins.Missing: myths | Show results with:myths
[105]
What Exalts Stradivarius? Not Varnish, Study Says
Dec 4, 2009 · A detailed analysis of the varnish on five instruments made by Antonio Stradivari reveals that he coated the wood with a rather humdrum mix of oil and resin.Missing: myths | Show results with:myths
[106]
Varnishes and Surface Coatings: Polymeric Varnishes - MediaWiki
Jun 23, 2021 · Polymeric picture varnishes are thermoplastic. Most polymeric picture varnishes are initially soluble in 100% aromatic hydrocarbons and most are also soluble ...
[107]
Varnishes and Surface Coatings: Special Considerations - MediaWiki
Jun 25, 2021 · Reversibility is questionable as even after aging, acrylic emulsion paints are at least partially soluble in solvents such as xylene.<|separator|>
[108]
Varnishes and Surface Coatings: Low Molecular Weight Varnishes
Jun 24, 2021 · The spray application should be very fine, depositing an even coat over the surface. It should then be brushed briskly with a badger brush to ...
[109]
ISO 15528:2020 - Paints, varnishes and raw materials for paints and ...
2–5 day deliveryThis document specifies procedures for the sampling of paints and varnishes, including coating powders, and raw materials used in their manufacture.
[110]
VOC Emissions in Varnishes: What Does the Regulation Say?
Mar 23, 2020 · The aim of this directive is to limit VOC emissions from certain paints and varnishes to prevent or reduce air pollution due to ground-level ozone formation.Missing: impact | Show results with:impact
[111]
Indoor Air Quality, VOC's, and Textiles: What to Know | Herculite Blog
Oct 2, 2023 · Environmental Impact: VOCs contribute to the formation of ground-level ozone and smog, which can harm the environment and human health. They ...
[112]
(PDF) The Quest for Cobalt-Free Alkyd Paint Driers - ResearchGate
Aug 7, 2025 · A variety of manganese and iron carboxylates have been studied as paint drying catalysts in the last two decades, but these often show drawbacks.
[113]
[PDF] Lead Paint Reformulation Technical Guidelines - SAICM Knowledge
to meet requirements for the phasing out of specif c lead compounds (e.g. EU REACH). ... Alternatives to cobalt driers are vanadium, iron, and manganese driers.<|separator|>
[114]
[PDF] Revision of the EU Ecolabel criteria for Indoor and Outdoor Paints ...
Feb 10, 2025 · The EU Ecolabel criteria for indoor and outdoor paints and varnishes set out in Decision 2014/312/EU were. 68 established in 2014. Commission ...
[115]
[PDF] Revision of the EU Ecolabel criteria for - Indoor and Outdoor Paints ...
May 7, 2024 · ❖Certifies that product/service is among the most environmentally-friendly in its class. ❖Increases the visibility of the product on the ...
[116]
The economics of paint recycling: A win for the environment
Jun 12, 2024 · The recycling program helps reduce leftover paint in landfills, allowing communities to conserve more resources, lessen supply chain stresses ...
[117]
The Benefits of Mineral Spirits Recycling with Maratek Environmental
This is where Maratek Environmental steps in, offering a sustainable approach to solvent waste management with solvent recycling and recovery services.
[118]
https://maratekenvironmental.com/the-benefits-of-mineral-spirits-recycling-with-maratek-environmental/
[119]
Low VOC Paint Market Size & Share Analysis - Mordor Intelligence
Jan 15, 2025 · The Low VOC Paint Market size is estimated at USD 9.34 billion in 2025, and is expected to reach USD 12.26 billion by 2030, at a CAGR of greater than 5.6% ...Missing: varnishes projection<|separator|>
[120]
[PDF] PAINTS, VARNISHES AND COATINGS - Carbon Footprint Italy
Product category definition. This document provides Product Category Rules (PCR) for the assessment of the impact on climate change of paints, varnishes and ...
[121]
[PDF] life cycle assessment study on wood coatings
Figure 4: Influence of thermal energy source in the carbon footprint per m2 wood surface coated with clear-coat (EG: electrical grid /. NG: steam from natural ...