What Is Varnish? – Our Guide to Protective Surface Treatments
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These days, there are so many options when it comes to finishing a wooden workpiece. Gone are the days when you had to crush up some berries and smear them on your wooden creations to set them apart from your neighbors. These days you have many options, from oil-based paints, latex-based paints, acrylic-based paints, and even metalized paint to choose from when selecting a finish. One of the most tried and true ways to finish a wooden workpiece without sacrificing the grain and texture of your wood is to use wood treatments like wood stain and varnish. So, let’s have a look at what varnish is, why it’s so popular, what it’s used for, what it is made of, and what the best way to use it is.
Table of Contents
- 1 What Is Varnish?
- 1. 1 What Is Varnished Used For?
- 2 Are There Different Types of Varnish?
- 2.1 Acrylic Varnish
- 2.2 Spar Varnish
- 2.3 Alkyd Varnish
- 2.4 Bituminous Varnish
- 2.5 Spirit Varnish
- 2.6 Exterior Varnish
- 2.7 Oil Varnish
- 3 Is Wood Varnish Safe to Use?
- 4 Varnish vs. Polyurethane
- 5 How to Varnish Wood
- 5.1 Prepare Your Workspace
- 5.2 Prepare Your Workpiece
- 5.3 Thin Out Your Varnish
- 5.4 Apply Your Varnish to Your Workpiece
- 5.5 Apply Your Second Coat
- 6 How Do You Look After Varnished Surfaces?
- 6.1 How Do You Replace Varnish That Has Faded?
- 7 Frequently Asked Questions
- 7.1 What Is Varnish Made Of?
- 7.2 Is Varnished Wood More Durable?
- 7.3 Is Varnishing Difficult?
What Is Varnish?
What is varnish? The term varnish is often used as a blanket statement for all manner of wood treatments like lacquer or polyurethane-based wood treatments that kind of interact with wood in the same way that real varnish does. This is why it’s often confused with real varnish, which is entirely unique in its composition and the characteristics it grants wood.
What varnish is in a technical sense has changed over the years, and considering that it’s been around for hundreds of years, it is now completely different from what our ancestors knew as varnish. Before, varnish was a term used to describe a wood treatment consisting primarily of wood sap and alcohol, but these days, varnish is a varying mixture of solvents, resins, and oils that are used to treat and seal the wood.
The exact composition of varnish can be altered to achieve a particular look or even work with a specific species of wood, which means that there is no textbook definition of varnish apart from it containing some combination of the aforementioned chemicals in varying quantities. Wood varnish is also inexpensive and highly effective as a means to seal and treat wood aesthetically.
While wood varnish isn’t exactly unique in what it does these days, back in the day it was one of the only ways to ensure that your wood was protected from the elements and looked good at that. This is because even today, varnish interacts with wood in a unique way, seeping deep into the wood’s fibers both altering its colors and sealing it.
What Is Varnished Used For?
What is varnish used for? Well, as we mentioned previously varnish is used to seal and treat wood aesthetically. Usually, it’s used to treat wood that will be situated in an environment that will have it exposed to things like heat, moisture, impact, and abrasion. Varnish works by engaging in a chemical reaction with the internal fibers of the wood, usually by darkening its hue and sealing it.
This makes it more challenging for things like water and insects to enter the wood, which can cause things like rot, mold, and an overall degradation in the wood. Furthermore, varnish also tends to repel moisture really well, which is great for small furnishings like coffee tables, bedside tables, and even wooden coasters which can come into contact with water, soft drinks, tea, and coffee often.
What does varnish do for the longevity of your wood? When you’re choosing a way to finish off your wooden workpiece, you could choose surface coatings like paint or polyurethane, the latter of which can be characterized as both a surface coating and a wood treatment, or you could choose wood treatments like varnish, which don’t just protect the exterior of your wood but the internal wood particles too.
What does varnish do for the aesthetic of your wood? Well, there are many ways for you to improve the look of a wooden workpiece, you could use pyrography, paint, stickers, wrapping, or you could choose wood treatment like stain and/or varnish. The latter not only improves the look of your wooden workpiece but it doesn’t obscure the grain of the wood and preserves its natural texture, which is ideal if you want to show off the wood species you’ve chosen.
Are There Different Types of Varnish?
We mentioned previously that there are many variations of varnish since the term is used to describe basically any wood treatment these days, but there are different types of varnish that have been designed to work in particular applications. This being said, let’s have a look at some of the types of varnish you could use when treating your workpiece for different applications.
Acrylic varnish is a really cool modern variation of varnish that has all of the advantages of conventional varnish without most of the drawbacks associated with it. Unlike ordinary varnish, the acrylic varnish is water-based and is clear in appearance, it also doesn’t yellow when exposed to natural or artificial light, which is probably why it’s used to protect paintings and crafts as an alternative to epoxy resin or similar clear coat substances.
Spar varnish has actually been around for a long time, and if you don’t know what it is it’s probably because you’re not well acquainted with boating or sea faring in general. A spar is essentially a mast on a boat that supports the sail, and back in the day, these were varnished to protect them from the elements. Varnish in those days needed to be re-applied regularly, but modern spar varnish is highly resistant to impact, abrasion, and the effects of prolonged exposure to sunlight and wind.
Alkyd varnish is one of the most versatile varnish variations out there. This varnish can be used for both interior and exterior furnishings as it doesn’t contain loads of volatile organic compounds (VOCs). Besides being graded for both indoor and outdoor use, alkyd varnish dries quickly and offers great protection from UV damage. What is alkyd varnish made of? Alkyd varnish is made from polyester resins, some fatty acids, and alkyd resins which make it an incredibly durable wood treatment.
Another type of varnish that has proven to be versatile and hard-wearing is the bituminous variety. This varnish is known for its dark black color which sets it apart from other varnish types which are usually a shade of yellow or completely transparent in appearance. Bituminous varnish is any type of varnish that has had the actual varnish replaced with bitumen which is a hydrocarbon consisting of a petroleum base.
Exterior varnish is pretty much the same thing as spar varnish, except that it has been modernized and refined to be far more durable and resistant to things like impact, abrasion, UV damage, and buffing from wind and sand. Exterior varnish is also known as spar urethane varnish because of its durability, and while it is pretty versatile and hard-wearing, it’s not great for time-sensitive workpieces as it’s fairly slow to dry.
Exterior varnish is pretty much the same thing as spar varnish, except that it has been modernized and refined to be far more durable and resistant to things like impact, abrasion, UV damage, and buffing from wind and sand. Exterior varnish is also known as spar urethane varnish because of its durability, and while it is pretty versatile and hard-wearing, it’s not great for time-sensitive workpieces as it’s fairly slow to dry.
Oil-based varnish is widely considered to be true varnish, but this is up for debate. Why is oil varnished considered to be true varnish? Well, it’s as close to the original idea of varnish as you get these days. Oil-based varnish is characterized as having a mix of drying oil and resin without the presence of any solvent. While this means it doesn’t dry as quickly as some other varnish variants, it does longer and offers a better layer of protection compared to faster drying alternatives.
Is Wood Varnish Safe to Use?
One could argue that safety is relative but keeping oneself in objectively good health is something you shouldn’t compromise on. This being said, varnish contains chemicals that can cause serious harm to both your skin and your respiratory system, this is why you should always practice extreme caution when working with varnish.
What can you do to ensure that you’re safe when you’re working with varnish? Well, the best way to go about it is to wear a face mask to protect your airways from the harmful fumes produced by the varnish, and gloves to protect your digits. You should also do your best to work in a well-ventilated area, or outdoors if you can help it.
The wood varnish contains volatile organic chemicals which do a really good job of treating wood, but they aren’t very good for you or the environment in general. This is why most new wood varnish variations contain more sustainably produced chemicals that have little to no impact on the environment.
If you’re concerned about your environmental impact, there are many alternatives to conventional varnish for you to choose from. You could opt for things like wood stain, which doesn’t contain any VOCs in some instances, or you could use completely natural wood treatments like tung oil or linseed oil which take some more maintenance but can be used free of consequence.
Varnish vs. Polyurethane
Choosing between varnish and polyurethane can be tough considering they’re both really durable, adorable, and do a good job of making wood workpieces look good. That being said, there are a few things that you should know about both varnish and polyurethane that will help you choose between the two if you’re having a difficult time deciding.
Varnish and polyurethane are similar, but there are some key differences between the two. Polyurethane is essentially a synthetic alternative to varnish which consists of a type of liquid plastic combined with resin. Polyurethane is sold in both oil-based and water-based forms, with the water-based being more environmentally friendly and fast drying, but not as durable.
Oil-based polyurethane wood treatment is far more durable than the water-based variation, and it seeps into the wood fibers to provide both internal and external protection. That being said, even though oil-based polyurethane is more durable than the water-based alternative it contains loads of VOCs which aren’t great for the environment or your health.
Varnish on the other hand is objectively superior to both water-based and oil-based polyurethane coatings. This is because varnish has more solids present in its composition, which makes it far more resistant to the effects of moisture and prolonged exposure to direct sunlight. It should come as no surprise then that varnish is used to treat furniture and other wooden workpieces that will be spending most of their time outdoors.
While varnish might be better as a protective coating than polyurethane is, it’s not great for use indoors thanks to the presence of VOCs in its makeup. That is why polyurethane coatings of both the water and oil-based variety are used more often indoors than varnish is, plus polyurethane coatings are better suited to handle foot traffic and constant contact which is why they’re often used to coat wood tables and flooring.
How to Varnish Wood
Knowing what varnish is and the different types of varnish that are available to you is all well and good, but if you don’t know how to use it to treat your workpiece, it won’t do you much good. This is why we have prepared a short tutorial detailing how to varnish wood workpieces, as well as some pointers to keep in mind when handling varnish.
Prepare Your Workspace
Regardless of what your project is, when you’re working with varnish it’s important to have your workspace adequately prepared. How do you prepare your workspace for working with varnish you ask? Well, you can start off by ensuring that none of your surfaces accidentally get any varnish on them. Lay down a tarp or some old newspaper on your work surface and on your floor immediately surrounding it.
When it comes to protecting yourself, you will need to take some more steps. Remember that varnish can affect both your skin and your respiratory system so you should gear up accordingly. In order to protect your hands, you should use gloves graded for use with solvents and oils, and to protect your airways you should wear a face mask or respirator.
Prepare Your Workpiece
When working with a wooden workpiece, it’s important to prepare the surface for the treatment process. More often than not, wood has an existing finish or similarly smooth layer such as laminate protecting the surface of the wood. Applying varnish to these surfaces without preparing them can yield poor results, so let’s have a look at how to prepare your surface for varnishing.
The best way to prepare a wooden surface for wood treatments like varnish is to sand the surface well. Sanding the surface ensures that there is enough exposed wood for the varnish to seep in and bond with the wood fibers. It also provides a bunch of surface friction, so the varnish doesn’t just run off onto your floor and shoes. Once you’re done sanding, ensure that you use a clean cloth or some compressed air (or a vacuum) to remove any wood particles, so they don’t get stuck in your varnish.
Thin Out Your Varnish
With most varnish, it’s easier to apply your initial coat if your varnish has been thinned out a little bit. Varnish is a bit thick in its consistency so applying it to your surface as-is can result in bubbles forming on the surface of your workpiece. This process also helps you to prevent runs on the surface of your workpiece, so it’s better to be safe than sorry when it comes to thinning out your varnish.
How do you thin out varnish, you ask? All that you need to do is get your hands on a clean, disposable container, and pour some varnish out into it. Next, you’ll need to get some mineral spirits and throw some into the container. How much, you ask? Around 20% of the total amount of varnish in the container should do the trick. Once you have your ratio, mix the substances together until it is appropriately thinned out.
Apply Your Varnish to Your Workpiece
When applying varnish to the surface of your workpiece, you should use a brush with natural bristles. If you don’t have one, a brush with a medium width will work just as well. Applying varnish is a bit different from applying paint, when applying paint, you’d usually follow the grain and length of the board, but when working with varnish you start against the grain first.
Why? This helps the varnish seep into the wood grain and the fibers underneath. Once you’ve covered the surface painting against the grain, go over it once more but this time following the direction of the grain. This seals the initial coat into the wood, just be sure to let each coat you apply set and dry for the manufacturer’s recommended time period before moving on to the next step.
Apply Your Second Coat
While you don’t need to apply a second coat of varnish to your workpiece, it can help a lot. Two coats of varnish ensure that the surface of your workpiece will last longer and that the seal you’ve created inside the wood is more durable too. Keep in mind that you should only apply your second coat if your first one has had a chance to dry completely.
Your second coat of varnish doesn’t need to be thinned out either, so be sure to compensate for the thicker consistency by using a bit less varnish on your brush this time around. You can apply your varnish by following the grain of the wood this time around and remember to allow your final coat to dry completely just as you did with the first.
How Do You Look After Varnished Surfaces?
Another advantage of using varnish as the surface coating for your wooden workpieces is that it’s pretty easy to maintain. Unlike paint or other wood treatments like tung and linseed oil, varnish does not chip or break as easily and is a lot easier to maintain compared to the aforementioned too. This being said, it’s a pretty good choice for a primary wood coating.
All that you need to do to clean your varnished workpieces is to wipe them down occasionally with a damp cloth. For more stubborn stains, you can use a small amount of soap and a damp cloth to lightly scrub away the stain. Just be sure not to overdo it or you’ll have to repair the spot you’ve scrubbed away.
How Do You Replace Varnish That Has Faded?
Wondering how to deal with a varnish that has faded over the years? Well, although varnish is pretty durable and doesn’t require a lot of maintenance it’s not infallible to damage. Varnish can deteriorate over time, and the best way to repair varnish coatings is to replace them entirely. While it is possible to patch certain areas, this doesn’t always work.
You could apply another coat of varnish over your existing one, but it most likely will turn out a bit patchy. The best thing to do is replace the existing finish completely by sanding the surface of your workpiece and then adding a new one. Ensure that your workpiece is clear of any wood and varnish particles before adding the next one though.
Now that you know what varnish is, what different types of varnishes are available to you, what the difference between varnish and polyurethane is, and how to use your varnish effectively, it’s time for you to get out there and put your newfound knowledge to the test. Remember to maintain your varnished surfaces well and to remove existing finishes completely when restoring your workpiece.
Frequently Asked Questions
What Is Varnish Made Of?
What is varnish made of? There are different types of varnish for different applications. The most commonly used type of varnish is the oil-based kind, which consists of a combination of resin and drying oil. Some variations contain colorants and/or dyes too.
Is Varnished Wood More Durable?
Is varnished wood more durable? Varnished wood is more durable than natural wood, which should come as no surprise considering that varnish is designed to make wood more durable. Varnish protects wood from light impact, abrasion, moisture, and rot.
Is Varnishing Difficult?
Varnishing can be challenging if you’ve never done it before, but the learning curve isn’t that steep. There are many techniques you can use to varnish wood; you can use a brush or you use a cloth to apply your varnish but just ensure that you work in a well-ventilated area.
Elijah Johnson is a 28-year-old painter and decorator who shares his skills and experience on resin-expert.com. Elijah trained as a painter and varnisher and started his own business in 2017. Since then he has built up a broad knowledge in designing facades, walls, ceilings and renovating all types of surfaces. Learn more about Elijah and resin-expert.com under the menu item about us.
What is a Varnish? Definition, Types of Varnishes and Classification
Varnishes are more or less transparent liquids which are used to provide a protective surface coating in much the same way as paints do” At the same time they allow the original surface to show but add a lustrous and glossy finish to it. All varnishes have basically the same components as paints.
What is Varnish? Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent. Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss sheens by the addition of “flatting” agents.
Types of Varnishes
Natural Resin Varnishes:
Body made from natural resin obtained from certain trees. Natural resin obtained from living trees or from fossils(which are superior) Vehicle in varnish is the same as used in oil-based paint. Resins dissolved in oil ► mixture heated to temperature (500-600OF) depending on the amount of gloss required. Oil and natural resin varnish ► OLEO RESINOUS varnish. Thinner and dryers used in varnish are the same as used in oil based paints
Modified natural-resin varnishes:
Made from natural resin ► altered by chemical action. Common resin is heat treated with glycerin to form a gum. This gum is treated as the body for the varnish. Less expensive varnish than the oleo resinous varnish
Synthetic resin varnish:
- Synthetic varnish produced by plastic industry
- Chemicals used include nitrocellulose, amino resins, silicon etc
- Vehicle most often the same as for oleo resinous varnish
- Coal tar derivatives may be used as thinners
- Dryer is also the same as for other types of varnishes
Classification of Varnishes
Long oil varnish:
- Long oil contain 40 to 100 gal of oil per 100 lbs of resin
- Takes longer time to dry
- Moderate gloss
- Marine and spar varnish belongs to this group
- Tung oil used ► impervious to water
Medium oil varnish:
- Medium-oil contain 12 to 40 gal of oil per 100 lbs of resin
- They dry faster ► harder
- Harder film than long-oil varnish but are not impervious to water
- Floor varnish belongs to this group
- Short oil resins:
Short-oil contain 5 to 12 gal of oil per 100 lbs of resin. Dry rapidly ► form a hard, brittle film that withstand much rough usage. Polishing varnish belongs to this group
How to Varnish
Overall, it can be stated that the improved element performed better than the traditional element in the series of earthquake simulations. This statement is based on an assessment of the risk of causing injury posed by each structure. The walls of the traditional corners were independent and unstable. Any additional force, such as another tremor or a strong wind or impact, could cause either wall to topple over, in an inward or outward direction. This represents an unacceptable level of risk. These buildings are one of the most deficient building systems from earthquake-resistance point of view. The main deficiencies include excessive wall thickness, absence of any connection between the two withes of the wall, and use of round stones (instead of shaped ones).
They are paints used for the treatment of masonry walls. Water instead of oil is used as a vehicle ► known as water-paint too. Powdered white chalk and glue boiled in water are mixed. Usually colored by mixing different pigments. All Distempers mixed with water only before being used. Distemper affected by weathering condition and takes off if washed ► to be used only in interior works. Cheap, durable and easy interior finish. Should be applied on clean and dry surface.
Varnish | it’s… What’s Lak?
This term has other meanings, see Varnish (meanings).
Lacquer is a solution of artificially synthesized or natural organic polymers (resins), in various organic solvents or water. It cures to a clear, glossy or matt film. Currently, there are varnishes that do not contain solvents. Their low viscosity is provided by oligomers that are able to cure in the presence of special substances – hardeners or catalysts. Varnishes are conditionally divided into thermoplastic and thermosetting. The curing of the lacquer film occurs either by evaporation of the solvent or by a chemical polymerization reaction.
Varnishes are solutions of solids in liquids that can either evaporate or dry out; solid substances are various resins, and ethyl (wine) and methyl (wood) alcohols, essential and vegetable drying oils serve as solvent liquids. The resin solution applied to the surface to be varnished dries, leaving a thin, transparent and shiny film (in practice called varnishing), the properties and qualities of which determine the merits of the varnish taken.
In foreign languages words fr. laque German Lack means paint obtained by precipitation of organic color pigments with metal salts. Such paints in Russian are called bakans, and the Russian word “lacquer”, as a designation for a liquid with the above properties, is translated in Western Europe by the words English. varnish German Firniss , fr. vernis .
There are many different resins used in the production of lacquers; they differ from each other in their properties, depending on which the advantages of the obtained varnishes are also located. Almost all resins dissolve in vegetable oils and only a few in essential oils and alcohols. Resins that are particularly hard and infusible are called copals. Of the liquids as solvents in the lacquer industry, the most commonly used are: ordinary alcohol, various varieties of turpentine and linseed oil. According to these solvents, varnishes are divided into three main groups: alcohol varnishes, turpentine and oil varnishes. Each of these groups has its own selection of resins, differs in its characteristic properties and purpose; the production of varnishes of each group requires special techniques and devices. The invention of varnish in Europe is attributed to the German monk Theophilus, who lived in the 12th century; at first, their preparation was surrounded by secrets and was carried out in a cell way. One must think that the first varnishes of European production were alcohol, and the first varnish factory on the European continent should be considered the factory of the French chemist Chenet, built in 1803.
Manufacture of oil varnishes was for a long time the privilege of England, and only when America, Portugal and Holland began to supply European markets with the same resins and copals that England used exclusively from her colonies, varnish production became generally available; however, the emergence of oil and varnish factories began only in the early 60s of the XIX century, that is, it coincides with the publication of research by the French chemist Violet on varnishes in 1862.
In Russia, the beginning of the production of oil carriage varnishes coincided with the development of the railway network. The first Russian plant of high grades of oil varnishes was the plant of the company I. S. Ossovetsky and K o , founded in 1874 in Moscow.
Alcohol varnish is a simple solution of resin in wine or wood alcohol. The latter is used on its own very rarely, but often serves as an admixture of wine alcohol in order to reduce the cost of varnish. Of the resins, sherlac (or shellac), sandarac and mastic are used. The resin is ground into a fine powder and poured with alcohol at 92-95°, in glass bottles or cylinders; dissolution is carried out at room temperature and accelerated by constant shaking. Resin is always taken in excess, in order to obtain a saturated solution. So the prepared varnish is filtered. This operation in the production of alcohol varnishes is considered the most difficult, it is carried out differently at different factories and is carefully guarded from outsiders, being considered the secret of the factories.
Ordinary straining is done with glass funnels lined with felt or cloth strainers; funnels are covered with glasses with small vents for air access. Straining is very slow and is always associated with a loss of alcohol. Alcohol varnishes get their name from the resins on which they are prepared. So, there are varnishes shellac, sandarach and sandarach-shellac. Mastic is not used on its own and serves as an admixture to the named resins. The admixture of mastic softens the varnish film, but increases its shine. Alcohol varnish thinned with alcohol is called varnish. In addition to the divisions mentioned, alcohol varnishes and varnishes also get their names from the color in which they are painted; so known are red, yellow, white and various colored paints and varnishes. Alcohol varnishes are used for varnishing and polishing wooden products. The varnish layer does not tolerate the influence of the external atmosphere and is especially afraid of dampness and sudden changes in temperature; in enclosed spaces, under normal room air conditions, it persists for a long time.
According to the hardness of the layer, the first place belongs to shellac varnishes; sandarach varnishes give a softer varnish, but they always turn out lighter. Colored varnishes are tinted with aniline paints, usually prepared on sandarak with an admixture of mastic, used for varnishing metal products, toys, tin capsules, etc. Their color, due to the instability of aniline pigments, is very fragile.
Similar to spirit varnishes, they are prepared by simply dissolving resins in turpentine. Turpentine varnishes are divided into white and black; for the preparation of the former, dammar resin is used, for the black ones, asphalt. Dammar varnishes are usually valued for their shade; the lightest, almost white, are called enamel. Dammar varnishes, yellowish, are prepared in three varieties, designated No. 1, 2 and 3, the only difference of which lies in the density of the shade; the lighter the varnish, the more expensive it is and goes under No. 1. The division into grades of asphalt varnishes is done depending on the admixture of rosin (harpius), which serves to reduce the cost of these varnishes to the detriment of their quality. Asphalt varnishes are also available in three grades, referred to in trade Nos. 1, 2 and 3.
The production of turpentine varnishes is usually associated with the production of oil varnishes, while the production of alcohol varnishes has nothing in common with the production of oil and turpentine varnishes. Turpentine varnishes are prepared as follows: dammar resins or asphalt are crushed into pieces the size of a walnut and poured into a copper pot heated on the hearth in this form. At temp. about 200 ° C, dammar and asphalt soften (resins prescribed for turpentine varnishes should not be brought to liquid melting; softened resin is removed from the hearth and poured over in a pot with turpentine, which quickly mixes with the resin, for which you only need to mix them thoroughly with an iron spatula, with a stirrer, and add turpentine in small portions. Usually poured on 10 parts of resin to 30 parts of turpentine by weight. Varnish, thus prepared, is drained in a warm state into settling tanks, where it settles for 2 to 3 weeks, and then enters the trade The use of turpentine varnishes is rather limited; their varnish film is soft, hygroscopic and does not withstand the influence of the external atmosphere.All varieties of dammar varnishes are used for varnishing surfaces painted in white or in the lightest colors. Black, asphalt varnish is used for varnishing cheap iron products or the most simple painting of the same color stains.0003
They have the widest and most diverse uses, and therefore their range is very numerous. The materials for the production of oil varnishes are linseed oil, turpentine and various varieties of copals. Linseed oil comes in the form of drying oil, which is harvested earlier. Turpentine is used only of high purity, usually French turpentine is used for lacquer work. and American, obtained in the production of rosin. Of copals – the most important material – all varieties of copal-kauri, copal-manilla, zanzibar, angola, sierra leone and westind copal (crystal) are especially preferred. The quality and merits of oil oils depend on the choice of all the materials mentioned. The production of oil oils is more difficult than alcohol and turpentine ones; in addition, it requires special skill, experience and careful observation. All production consists of the following operations:
- preparation of drying oil
- melting copals
- varnish cooking
Lacquer drying oil is prepared from dry, settling linseed oil; the oil is heated to a temperature of 260 ° C in a special copper open cauldron over a bare fire, and during the cooking of drying oil, a little lead sugar and manganese boric acid are added to it. The welded drying oil should dry on the test glass for 18 hours, not stick and be a transparent, colorless, shiny and elastic film. Such drying oil is not only a solvent for copals, but itself serves as the main component of the lacquer shell. Linoxein of drying oil, combining with copals, destroys their fragility, gives elasticity to the varnish film and serves as an important condition for the strength and stability of oil varnishing. Lacquer drying oil is prepared for storage, stored in settling tanks, and only in a clean, settled form is used for the preparation of varnish.
Copal sorting also plays an important role in production. Commercial grades are obtained in pieces of various sizes, varying degrees of transparency and color, and even different hardness. When sorting, pieces are selected that are uniform in color, purity, size and hardness, and each variety separately serves to prepare a special variety or No. L. Crushing of copals is carried out using a manual machine used for chopping sugar; with a certain skill, one person per day can grind about 6 pounds of copal.
The sorted, crushed copal goes to the smelter and then to the smelter. The selection and relative proportion of them for cooking is known. varieties or, as they say, the specialty of L. and is usually the secret of factories. Mixing combinations, due to the huge selection of copals and other resins, are countless, and each plant has its own methods and recipes. Different copals have different hardness and therefore different melting points. There are copals, such as Zanzibar, Sierra Leone, and others, melting above 400 ° C, therefore, when melting, such an order should be observed so that a portion of refractory copal is poured into the melting pots first and after it is melted, the more fusible copals required by the recipes, etc., are added. resins. This precaution reduces the burning of resins and gives lighter shades of L., but in practice, craftsmen almost always mix crushed copals at once and the mixture is subjected to simultaneous melting. Melting and boiling are the most complex and difficult operations in the production of L. When melting copals, an abundant release of volatile products, which are easily flammable, occurs, so the arrangement of lacquer hearths requires special devices. The smelting of copals and the boiling of limes at large factories are carried out in large copper cauldrons with a capacity of 30–40 buckets (370–490 liters) placed on hearths arranged in the floor of the lacquerery. Above the boiler is a funnel-shaped iron cap, with draft, to remove volatile products. The boiler is equipped with a chain, by means of which, with the help of a crane installed nearby, it can be removed from the hearth at any time. Throughout the smelting, the beginning of which is determined by the appearance of heavy vapors and gases in the form of smoke, the copal is stirred with an iron stirrer.
At the end of melting, which is recognized by the cessation of smoke emission, the boiler is removed from the hearth, and a certain portion of drying oil, preheated to 250 ° C, is poured into the melted copal, with constant stirring, in parts; then the boiler is again placed on the hearth and cooking begins. This operation requires special knowledge and experience. All the dignity of L. depends on the definition of the end of its cooking. L. undercooked or overcooked is rejected. The end of cooking is determined by constant samples of boiled L. These samples are made using a glass rod, with which boiled L. is taken in drops on a flat glass, and the end of cooking is recognized by the color, density and stickiness of these drops.
Cooked L. is removed from the hearth and allowed to cool to 200 °C. When this temperature is reached, with constant stirring, a pre-weighed portion of turpentine is poured in parts, and the boiler is placed under a hood with draft, since dilution of L. with turpentine is accompanied by a strong release vapors and gases. Then L. is allowed to cool and the cooled, finished varnish is poured into settling tanks.
At small factories, and some L. and at large factories, they cook in smaller copper pots, the capacity of which does not exceed 4-5 buckets (50-60 liters). For such pots (manual), special hearths are arranged and the pots themselves have a special design with a helmet that removes gases into the exhaust pipe and an opening through which the contents of the pot are constantly mixed with a stirrer. Melting and boiling are carried out in exactly the same way as in large boilers.
The following is considered to be the classic recipe for oil L.: 14 hours of copal, 43 hours of drying oil and 25 hours of turpentine. At the same time, however, it should be noted that the whole essence of lacquer production is the choice and proportion of copals, the specifics of the preparation of drying oil, and the method of melting copals and boiling oil. The sump must be at least 20° R (25° C) and free from moisture. Tanks are made of boiler iron with a capacity of 50 to 100 pd. (820-1640 Kg.) L. For each variety L. must have at least two reservoirs, since settling lasts at least 6 months. The settled L. is poured and soldered into tin gallons, containing from 5 lbs. (2 Kg.) to 1 pd. (16 Kg.) L., in which L. and go on sale. Oil L. are subdivided into carriage, painting and special. Carriage coats are distinguished by: preparatory coats for preparing the surface for painting, coats Nos. 2 and 3 for the first layers of lacquering to be painted for sanding, and sheets Nos. 1 and 0 for the last coats of varnishing of carriages. Of L. painting, we note L. sexual, which are several numbers, in color and quality. They are distinguished by a special hardness of the film and are suitable for varnishing painted floors. L. painting copal, copal-amber – also in several numbers – are intended in general for varnishing on wood and on any color, if gloss is required and if the surface is subject to the influences of the external atmosphere. Of special varnishes, various types of varnishes are of great importance: leather, oilcloth, wallpaper, tin, black Japanese, etc.
In essence, car paint is a very clear, highly refined alkyd resin with special additives.
Highest quality HS clearcoat for use in automotive aftermarket and automotive design work. It is a high-transparency lacquer that provides the highest surface quality, excellent brightness and gloss. It is weather resistant, UV resistant, has excellent elasticity and polishes excellently.
Depending on the country of manufacture and the make of the vehicle, varnishes from different manufacturers can be used. It is no secret that in the production of cars in different countries they use different technologies, for example, in the production of their cars, German manufacturers turn to the drying mode in high-temperature chambers, which significantly saves time. But it does not save resources and electricity. But the Japanese auto industry, due to limited resources in terms of geographical location, went the other way, where drying is carried out using a minimum amount of electricity and heat, while the process is accelerated due to chemical catalysis and special chemical drying accelerators.
This varnish has sufficient strength, but some precautions must still be observed. It is strongly not recommended to wipe a dirty car with rags, brushes or other hard devices, especially when it is dry. Also, quite serious problems can be caused by bags, boxes and other items placed on a dirty body, and subsequently removed or moved from it (dust and sand particles, always invisibly present on the car body, will play the role of an abrasive and leave deep scratches on your car which will be difficult to eliminate later).
Building varnishes. General information
Varnishes are a large group of materials that are solutions of film-forming substances (resins or polymers) in organic solvents or water. After drying, they form a solid transparent (colorless or colored) film.
Varnishes are used to obtain transparent coatings when it is necessary to protect and at the same time preserve or emphasize the structure of the surface to be painted, especially valuable woods. In this case, the varnish is applied to the prepared surface of the product. Lacquering as the last layer in a multi-coating system will give it a good appearance and improve performance.
Bituminous varnishes are obtained from bitumen of special grades with the addition of various resins and oils. When dried, bituminous varnishes form a black film that is resistant to water and some chemicals. However, the anti-corrosion properties of the bitumen film in atmospheric conditions are not high enough. Most often, bituminous materials (lacquer BT-577, paints BT-177 and BT-184) are used for temporary protection of metal, since they are much cheaper than other materials.
Oil varnishes are obtained by dissolving natural or artificial resins in drying vegetable oils with the addition of desiccants and solvents. From natural resins, rosin, shellac and amber are more often used. Kopals, dimmaru, sandarak, mastic, akaroid, imported from India and other countries, are used mainly for artistic and decorative painting. Natural resins, except for rosin and amber, are scarce materials and are used to a limited extent. They are replaced by synthetic resins (polymers) – perchlorovinyl, alkyd, inden-coumarone, phenol-formaldehyde, etc.
As a rule, oil varnishes form hard transparent films of a yellowish color. Due to the low weather resistance of the coatings, oil varnishes are used for interior finishing, for example, to give shine to worn wood flooring.
Alkyd lacquers are the most commonly used lacquers in everyday life. They are solutions in organic solvents of synthetic alkyd (pentaphthalic or glyphthalic) resins. Films of alkyd varnishes are hard, transparent, slightly colored; possess good adhesion to various surfaces, water-resistant. Are applied both to internal, and to external works. (Although traditionally lacquers are rarely used outdoors.)
In everyday life, alkyd varnishes are mistakenly called oil varnishes. This is not true because although vegetable oils are used in the manufacture of alkyd resins, alkyd varnishes differ from oil varnishes in chemical composition and structure, and significantly surpass them in properties.
Here are some basic information about the most suitable alkyd varnishes for home use.
Lacquer GF-166 (PF-283) is a solution of alkyd glyphthalic (pentaphthalic) resin modified with vegetable oils in an organic solvent with the addition of NF-1 siccative. Gives a uniform glossy transparent film. It is intended for a covering on oil paints, wooden and metal surfaces outside and in rooms. Apply by brush, roller or spray gun. It is diluted if necessary with white spirit or RS-2 solvent. Varnish consumption for a single-layer coating is 70-75 g/m2. The drying time of a single layer coating is 48 hours.
Lacquer GF-177 is a solution of glyptal resin modified with cottonseed oil in organic solvents with the addition of a siccative. It is intended for coating wooden, primed or painted metal surfaces operated in atmospheric conditions. Also recommended for painting kitchen furniture. Before work, the varnish is diluted with solvents 649, 650, RS-2, solvent or turpentine and filtered through 2 layers of gauze. For preservation, wooden surfaces are recommended to be additionally treated with anti-rotten compounds, filled and painted (for example, stained). Primed or previously painted metal surfaces should be sanded and wiped with mineral spirits. The duration of drying of a single-layer coating is 24 hours, the second layer of varnish is applied with a brush after 36 hours. Consumption of varnish for a single layer coating — 60 — 90 g/m2.
Nitrolacquer (nitrocellulose varnishes) is obtained by dissolving cellulose nitrate in a mixture of active organic solvents. The properties of varnishes are regulated by introducing various resins (alkyd, amino-formaldehyde, etc.) into the composition. Nitro-varnishes form hard transparent, almost colorless quick-drying films. Most often, nitrovarnishes (NTs-221, NTs-222, NTs-218, NTs-228, etc.) are used for varnishing wood products.
Epoxy varnishes are solutions of epoxy resins in organic solvents. Before varnishing, a hardener is added to them, the amount of which depends on the type of resin and hardener, curing conditions and is indicated in the instructions for use. Lacquer films have high water and alkali resistance, mechanical density, adhesion to various materials, but are not weather resistant enough. In everyday life, epoxy varnishes are often used for making putties, gluing, making souvenirs and other purposes.
Alcohol varnishes and varnishes are obtained by dissolving some natural shellac resins, sandarak in alcohol (lacquer concentration 30-45%, varnishes 15-25%). These materials give a coating with good mechanical strength and adhesion to various surfaces, high gloss. Coatings are well polished, but have low water resistance.
Oil and alcohol varnishes are produced in small quantities due to scarce and expensive natural raw materials. They are mainly used for special purposes, for example, in the manufacture of musical instruments.
Petroleum polymer varnishes are a new group of varnishes that are significantly cheaper than oil-resin varnishes, but can replace the latter, surpassing them in resistance to detergents and various reagents.
These varnishes (NP-2129, NP-2130) are obtained in the form of compositions, solutions of petroleum polymer resins in organic solvents with various modifying additives.
Alkyd-carbamide varnishes (MCh-52) are a solution in organic solvents of a composition of alkyd resin with amino-formaldehyde (urea-melamine-formaldehyde) or taken together in a certain ratio. Air-dry at normal temperature only when introduced into them before using a given amount of acid hardeners. With a hardener, the shelf life of the varnish is limited from several hours to several days. Such materials can dry without hardener, but with hot drying (80-120 °C). Alkyd-urea varnishes with hardeners form rather quickly air-drying films, which are distinguished by increased hardness, good water and wear resistance. These varnishes are used to coat parquet floors, furniture and various wood products used indoors.
Polyurethane and alkyd urethane varnishes produce films with exceptionally high mechanical strength and wear resistance. They varnish parquet floors, furniture, musical instruments.
Polyacrylate lacquer AK-156 is a solution of acrylic copolymer in a mixture of organic solvents with the addition of organic dyes. Designed to create a decorative coating on metal, glass and wood of various species. The varnish gives the wood the desired shade and emphasizes its texture, protects the materials from atmospheric influences. Available in various colors: colorless, yellow, orange, red, blue, green, brown.
Stir the varnish thoroughly before application; if necessary, can be thinned with acetone or Thinner 646. Drying time for each coat is 24 hours, for a single coat 60 g/m2 of varnish is required.
Particular attention should be paid to special varnish compositions used to protect wood. These varnishes give the surface a decorative look, while protecting the wood from mold, rot, insect damage and weathering. Available in various colors. Are applied to external and internal works. They can be used on wooden exterior walls, cornices, doors, windows, etc. They reliably protect wood from mold and decay for several years.
- petroleum resins
- Nail polish
- Additional information about
- paint varnishes
When writing this article, material from the Encyclopedic Dictionary of Brockhaus and Efron (1890-1907) was used.
| The data in this article are given as of the end of the 19th century
(requires conversion to modern units of measurement).
You can help by updating the information in the article.
What is Varnish and what types of varnishes are there?
Varnishes are more or less transparent liquids that are used to provide a protective coating to a surface in much the same way that paints do.” At the same time, they allow the original surface to be displayed, but give it a shiny and glossy finish. All varnishes have basically the same components as paints.
What is varnish? Lacquer is a transparent, hard, protective treatment or film, mainly used for woodworking, but also for other materials. Traditionally, lacquer is a combination of drying oil, resin, and a thinner or thinner. Lacquer finishes are usually glossy, but can be designed to achieve satin or semi-gloss hues by adding “flattening” agents.
Natural resin varnishes:
Natural resin body obtained from selected trees. Natural resin obtained from living trees or from fossils. The vehicle in lacquer is the same as in oil-based paint. Resins dissolved in oil ► mixture heated to a temperature (500-600OF), depending on the amount of gloss required. Oil and natural resin varnish ► OLEO RESINOUS varnish. The thinners and dryers used in varnishes are the same as those used in oil-based paints.
Modified natural resin varnishes:
Made from natural resin that has been chemically modified. Regular resin is thermally treated with glycerin to form a gum. This gum is considered as a body for varnish. Less expensive polish than resinous oleo polish.
Synthetic resin varnish :
• Synthetic varnish produced by the plastics industry
• Chemicals used include nitrocellulose, amino resins, silicon, etc.
• Vehicle is most often the same as for oleo tar varnish
• Coal tar derivatives can be used as thinners
• Dryer is also the same as for other types of varnishes
Long oil varnish:
Medium Oil Varnish:
- Medium Oil contains 12-40 gal oil per 100 pounds of resin
- They dry faster ► stronger
- Harder film than pre-oiled lacquer, but impervious to water
- This group includes floor varnish
Short Oil Resins:
Short Oil contains 5-12 gal of oil per 100 pounds of resin.