Varnish is a transparent, hard, or protective coating primarily used in wood finishing but also for other materials. Varnishes are traditionally a combination of drying oils, resins, and solvents or solvents. Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss sheens with the addition of a "flatting" agent. Varnishes have little or no color, are transparent, and have no additional pigments, as opposed to wood paints or stains, which contain pigments and generally range from opaque to translucent. Varnish is also applied on top of wood stains as a final step to achieve the film for gloss and protection. Some products are marketed as combined dyes and varnishes.
Once applied, the lacquer in the varnish either hardens directly, immediately after the solvent has completely evaporated, or hardened after solvent evaporation through a curing process, in particular the chemical reaction between oil and oxygen from the air (autoksidation) and chemistry. reaction between varnish components. The varnish resin is "dry" by evaporation of the solvent and harden immediately after drying. Acrylic varnish and "dry" water after evaporation of water but will experience a long period of curing. The oil, polyurethane, and epoxy lacquer remained liquid even after the evaporation of the solvent but rapidly began to heal, undergoing successive stages of liquid or syrup, becoming tacky or sticky, to dry gummy, to "dry to the touch", to hard. Environmental factors such as heat and humidity play an enormous role during the drying and varnish preservation. In classical varnish the healing rate depends on the type of oil used and, to a certain extent, on the ratio of oil to the resin. Drying time and preservation of all varnishes can be accelerated by exposure to energy sources such as sunlight, ultraviolet light, or heat.
Video Varnish
Keamanan
Due to flammable problems, many product lists contain safety precautions for storage and disposal for flammable varnish and drying of oil, and the materials used to apply varnish may spontaneously burn. Many varnishes contain derivative oils (eg linseed oil), synthetic oils (eg polyurethane) or resins as binders in combination with organic solvents. It is highly flammable in its liquid condition. A very important note, which often looks excessive, all the oil dryers, some basic materials (including paints), and many polyurethanes generate heat (exothermic reactions) during the curing process. Thus, cloth and paper soaked in oil can burn and burn, even hours after use if proper precautions are not taken. Therefore, many manufacturers make a list of appropriate disposal practices for wipes and other items used to apply the final results, such as disposal in a container of water
Maps Varnish
History
Early varnish was developed by mixing pine resin, for example - with a solvent and applying it with a brush to get the golden and hardened effect seen in today's varnish. Varnishing is a well-known technique in ancient Egypt.
Varnishing is also recorded in the history of East and South Asia; in India, China and Japan, where the practice of varnish works, a species of varnish application, is known on a very early date. Tang China used medieval chemical experiments to produce varnishes for clothing and weapons using complex chemical formulas applied to undersea underwater silk underwear, creams intended to polish bronze mirrors, and many other useful formulas.
Etymology
The word "varnish" comes from the Latin vernix , which means smelly resin, the etymology that comes from the Greek
Classical lacquer components
Dry oil
There are many types of drying oils, including linseed oil, tung oil, and walnut oils. It contains high levels of unsaturated fatty acids.
Resin
Resins used in varnish include amber, kauri gum, resin, copal, resin (pine resin), sandarac, balsam, elemi, mastic, and others. Lak is also resin. In the 1900s in Canada, resins from local trees were used to complete the piano. As a result, these antique pianos are considered difficult to repair. However, lacquer can be used on top of existing resins with sufficient time permissible conditions for thin layers to heal. Thus the original result can be restored to its original gloss while maintaining age-related colors and sparkle.
Solvents (traditional turpentine)
Traditionally, turpentine (organic) is used as a thinner or solvent, but has been replaced by mineral mineral turpentine substitutes such as white spirit or thinner, also known as "mineral spirit".
Type
Violin
Violin varnishing is a multi-step process involving some or all of the following: primer, sealer, soil, color coating, and clear top layer. Some systems use dry oil varnish as described below, while others use varnishes (or solvents). Repair in repair or recovery is only done with spirit varnish.
Drying oils such as walnut oil or linseed oil can be used in combination with resin, copal, resin or other resins. Traditionally, oil is prepared by cooking or exposure to air and sunlight, but modern "oil stands" are prepared by heating oil at high temperatures without oxygen. Finer resins are sometimes available as translucent solids and then "run" by cooking or melting literally in a pan over heat without solvent. The condensed oil and resin are then cooked together and diluted with turpentine (away from open flames) into brushed solution. The material and the process of violin varnish are very diverse, with some old examples showing defects (eg cracks, grazing) associated with an incompatible varnish component.
Some violin finishing systems use vernice bianca (egg white and gum arabic) as a sealer or ground. There is also evidence that fine mineral powder, perhaps volcanic ash, is used in several reasons. Some violins made in the late 18th century used cow blood to create a very red color. Today this varnish will fade and is now a very warm dark orange.
Resin
Most varnish resin or "rubber" comprises natural materials, plants or insects dissolved in a solvent, called a sponge varnish or solvent solvent. The solvent may be alcohol. , turpentine, or petroleum-based. Some resins dissolve in alcohol and turpentine. Generally, petroleum solvents, ie mineral spirits or paint thinners, can replace turpentine. Resins include amber, resin, copal, resin, sandarac, elemi, benzoin, mastic, balsam, lacquer, and lots of lacquers.
Synthetic resins such as phenolic resins can be used as a secondary component in certain varnishes and paints.
Over the centuries, many recipes have been developed that involve combinations of resins, oils, and other materials such as wax. It is believed to provide a special tone quality for musical instruments and thus sometimes the secret is carefully guarded. The interactions of different materials are difficult to predict or reproduce, so professional experts are often appreciated.
Shellac
Lak is a widely used solvent single component resin which is soluble in alcohol. It is not used for outdoor surfaces or where there will be repeated contact with water, such as around the sink or bathtub. The source of shell resin is the fragile or scaly lacquer secretion of the female lacquer insect, Kerria lacca , found in the Assam and Thai jungles and harvested from the bark of the tree where it is stored to provide cling to the luggage. Lak is the basis of French polish, which for centuries has been the final choice for fine furnishings. Determined "dewaxed" plates have been processed to remove wax from indigenous lacquer and may be used as primary substrate and sanding substrate for other solutions such as polyurethanes, alkyds, oils and acrylics.
Prepared flakes are usually available in "clear" and "amber" (or "orange") varieties, generally as "three-pound pieces" or three pounds of dry, dry powder for a gallon of US alcohol. Other natural colors such as ruby ​​â € <â €
Varnish is manufactured commercially modern using some form of alkyd to produce protective film. Alkyds are chemically modified vegetable oils that operate well under various conditions and can be engineered to speed healing rates and thus harden more quickly. Better (and more expensive) exterior vans use alkyds made from high performance oils and contain UV-dampers; this improves gloss retention and extends end life. Various resins can also be combined with alkyds as part of a commercially available "oil" lacquer formula.
Spar varnish
Spar varnish (also called sea varnish ) was originally intended for use on boats or spar vessels, to protect wood from marine and weather effects. Spars bend under their screen load. The main requirements are water resistance and also elasticity, so it remains attached while sparflection. Elasticity is a pre-condition for weather damping as well, since a cracked end result will allow water to enter, even if the remaining film is watertight. Appearance and gloss is a relatively low value. Modified tung oil and phenolic resins are often used.
When first developed, no varnish has good UV resistance. Even after more modern synthetic resins become resistant, true spar varnish maintains its elasticity above other values, even if this requires a compromise in its UV resistance. Spar varnish thus not is certainly the best choice for outdoor wood that does not need to be bent.
Nevertheless, the widespread perception of "marine products" as "tough" causes domestic domestic varnishes to be labeled "Spar varnish" and sold on the basis of their weatherproof and UV virtues. These claims may be more or less realistic, depending on each product. Only relatively recently available spar varnish can offer effective elasticity and UV rays resistance.
Drying oil
By definition, oil draining, such as flaxseed and tung oil, is not a true varnish although often in modern terms they achieve the same thing. Drying oil heals through an exothermic reaction between the polyunsaturated part of the oil and oxygen from the air. Initially, the term "varnish" is called a finish made entirely of resin dissolved in an appropriate solvent, either ethanol (alcohol) or turpentine. The advantage to finish in previous centuries was that the resin lacquer had a very rapid cure rate compared to oil; in most cases they recover practically as soon as the solvent has completely evaporated. Conversely, unprocessed or "raw" oil can take weeks or months to heal, depending on the temperature of the environment and other environmental factors. In modern terms, "boiled" or partially polymerized drying oils with additional siccatives or dryers (chemical catalysts) have a healing time of less than 24 hours. However, certain non-toxic byproducts of the preservation process are emitted from the oil film even after being dry to the touch and for a considerable period of time. It has long been a tradition to combine desiccant oil with resin to get the advantageous features of both substances.
Polyurethane
Polyurethane lacquer is usually hard, abrasion resistant, and durable coating. They are popular for wooden floors but are considered by some wood coatings to be difficult or unsuitable for finishing furniture or other detailed pieces. Polyurethanes can be compared in violence against certain alikuds but generally form harder films. Compared to simple oil lacquers or lacquers, polyurethane varnishes form harder films, which are obviously harder and more water resistant. However, regular polyurethane thick films can be removed laminate if exposed to heat or shock, film fracture and leaving white patches. This tendency increases with long exposure to sunlight or when applied on softwoods such as pine. This is also partly due to lower polyurethane penetration into the wood. Various priming techniques are used to address this problem, including the use of specific oil varnishes, dewaxed dyes, clear translucent epoxy seals, or "oil modified" polyurethanes designed for that purpose. Polyurethane varnishes may also have no dry oil luster such as "hand-rubbed" such as linseed oil or tung; Instead, it is able to "build" films much faster and higher, reaching two layers that may require a lot of oil applications. Polyurethane can also be applied over straight layers of oil, but due to the relatively slow recovery time of oils, the emission of certain chemical byproducts, and the need for oxygen exposure from the air, it should be noted that oil is sufficiently cured. to receive polyurethane.
Unlike drying oils and recovering alkyds, after solvent evaporation, after reaction with oxygen from the air, the polyurethane coatings properly heal, after solvent evaporation, by various chemical reactions in the original mixture, or by reaction with water vapor from the air. Certain polyurethane products are "hybrids" and incorporate various aspects of the parent component. Polyurethane "oil modified", either water-borne or solvent-containing, is currently the most widely used wood floor finish.
The use of polyurethane lacquer exterior can be a problem because of its high susceptibility to damage through exposure to ultra-violet light. All varnishes are clear or transparent, and indeed all polymer films (eg paints, stains, epoxies, synthetic plastics, etc.) are susceptible to this damage in varying degrees. Pigments in paints and stains protect against UV damage. UV-absorber is added to polyurethane and other varnishes (eg spar varnish) to work against UV damage but decreases effectively for 2-4 years, depending on the quantity and quality of UV-damper added, as well as its severity. and the duration of sun exposure. Exposure to water, humidity, extreme temperatures, and other environmental factors affects all completed. Instead, wooden items taken from the Egyptian pyramids have a fresh and fresh appearance after 4000 years of storage. Even there, however, fungal colonies are present, and fungi and fungi are another category of entities that attack varnish. In other words, the only layer of varnish with perfect durability is stored in a vacuum, in darkness, at a low temperature and unchanged. If not, care and care is required.
Lacquer
The word lacquer refers to a dry, solvent-based varnish or paint. Although their names may be similarly lowered, the lacquer is not the same as lacquer and is not soluble in alcohol. Lacquer is dissolved in thin lacquers, which are highly flammable solvents which usually contain butyl acetate and xylene or toluene. Lacquer is usually sprayed, inside an overheated spray booth and minimizes the risk of burning.
Outside America, the rule of thumb is that the finished wood formulated for spraying is shellac, but if it is formulated for brushing then it is varnish. Thus, most of the wood furniture is varnished.
Lacquer can be considered different from varnish because it can be dissolved subsequently by the solvent (as dissolved when applied) and does not change chemically into solids like other varnishes.
Acrylic
Acrylic lacquer is usually a water-borne varnish with the lowest refractive index of all end products and high transparency. They refuse yellowing. Acrylic has the advantage of water purification and the lack of solvent smoke, but it usually does not penetrate into the wood like oil. They sometimes lack the brushability and self-leveling properties of solvent based coatings. Generally they have good UV resistance.
In the art world, varnish offers dust resistance and harder surfaces than bare paint - they sometimes have the benefit of ultraviolet light resistors, which help protect the artwork from fading in light exposure. Acrylic lacquer should be applied using an insulating layer (permanent shield, protector between painting and varnish, preferably soft and glossy gel medium) to make varnish removal and overall conservation easier. The acrylic varnish used for such end-release art cover is usually mineral-spirit based, rather than water-based acrylic.
Two parts
Various epoxies have been formulated as varnish or floor coating where the two components are mixed directly before the application. Often, two parts have the same volume and are referred to as "part A" and "part B". True polyurethane is a two-part system. All two-part epoxy has a "pot-life" or "working time" in which epoxy can be used. Usually pot-life is only a few hours but also very dependent on temperature. Water-based epoxies and solvents are used.
Conversions
Used when finishing fast, difficult, and hard desirable, such as for kitchen cabinets and office furniture. Present in two parts: resin and acid catalyst. The first is a mixture of amino and alkyd resins. The acid catalyst is added just before the application in the ratio specified by the manufacturer. Most produce minimal usage. There are, however, two disadvantages to this settlement. The first is that after the drug is complete, it secretes formaldehyde, which is toxic and carcinogenic. The second is that the end result can be cracked or craze if too many layers are applied.
See also
- The Artist's Handbook of Materials and Techniques
- Brightwork
- Varnish desert
- Tack cloth
- UV layer - print results
References
- Bob Flexner (1993). Understanding Wood Finishing: How to Choose and Apply the Right Edge . Rodale Press: Emmaus, PA.
External links
- Tung Oil and Linseed by Steven D. Russel
- Varnish for musical instruments
- Varnish for Violin and similar instruments (archive.org)
- Instructions for Making Acoustic Varnish Proven Using Only Five Materials by Keith Hill
Source of the article : Wikipedia
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