Wood is a living and natural material that varies before environmental changes and can even be attacked by insects and fungi. Therefore, it is necessary to protect it, especially outdoors, where these attacks are bigger and more common.
For this, there is a variety of products, each with its advantages and disadvantages. This time, we will focus on the stain, perhaps the most common finish for wood outdoors, and we will compare it with other frequent options.
What is Lasur for Wood?
The stain is a type of finish, used mainly in wood outdoors, to protect it from the weather and the attack of fungi and xylophagous insects. It is a compound based on elastic resins, dissolved in solvents or water, that penetrates the wood without forming a film that isolates it, that is, keeps the pore open so that the wood breathe.
It can be used to protect all types of exposed wood: pergolas and other structures, decks, outdoor furniture, walkways, fences, doors and windows, etc.
As with many other products, it is common for a product to be known by the name of the manufacturer or brand, when it has a strong presence in an area. For example, in some Latin American countries, the word Cetol (manufacturer) is used to refer to lasur. Some even wonder if lasur and Cetol are the same.
Features and functions that the product must meet
Some of the properties of the lasur are:
- It does not create a film that insulates the wood, but penetrates it. That is, it is a finish with open pores, which facilitates the natural regulation of moisture in the wood (water balance).
- Repels water.
- It is an elastic finish that supports the dimensional changes of the wood without cracking. These changes are due to environmental variations, always greater outdoors.
- Although it is mainly used on wood, it can also be applied to other porous materials, such as clay or some types of stone.
- It can improve and maintain the natural appearance of the wood. What does not happen with all finishes applicable to wood.
- Reduce maintenance. Not only is it necessary to renew the application less frequently (between 4 and 7 years under normal conditions), but this renewal is easier, as prior sanding or peeling is not always necessary.
- Offers protection against insects and fungi. It is common to incorporate fungicides and insecticides into the product.
- UV protection
- Its degradation is due to erosion, that is, its residues are in the form of dust and not in layers as occurs with other products such as varnish.
Types of Lasur for Wood
Today you can find lasur for water and also solvent. The latter, based on alkyl resins modified with oil or urethane, are the ones that have been traditionally used, but have problems with ultraviolet radiation (harden) and hydrolysis, which degrade the product.
For a few years, water stains were imposed. The improvement in this type of product was especially considerable. They are less toxic, non-flammable, dry quickly, cleaning during application is much greater, do not have such an aggressive odor and offer a long durability.
Finishes and colors
As with other products, such as varnishes, lasures are available in different finishes: shiny, matte and satin (midpoint between shiny and satin).
In terms of shades, this type of finish allows stain the wood. For example, you can find white, red or blue lasur in our paint store or in the DIY center. Although the most common are those offered by the typical tones of wood or transparent.
It is worth mentioning that the range of colors and finishes is greater in water-based pigments.
Lasur for wood or varnish Which one suits me?
This is a common question when renovating or replacing the finish of a piece of furniture, door or any other wooden object: what is more convenient for me, varnish or paint? You cannot always give a strong answer to that question, although in some situations you can.
As we already know, the wood expands or contracts slightly in the face of environmental changes, so the finish to be applied must be able to adapt to these changes. That is, it must be elastic, especially in outdoor environments, where these variations are more significant.
What the varnish does is cover the wood by creating a layer of “plastic”. This may have some elasticity, but never that offered by an open pore product, so it will crack over time.
Therefore, in exposed wood it is recommended to use paints instead of varnishes.
In interiors, where environmental changes are much more limited and, therefore, the possibilities of cracking are less, the varnish may be preferable in view of greater surface resistance and greater durability.
Lasur for wood or oils?
Another common type of finish for wood is oils, teak and linseed being the most used.
They are similar to paint in that they have an open pore finish that does not form a film and allows the wood to breathe.
On the other hand, oils are natural products that deeply nourish wood. This is a somewhat risky statement, since most of the wood oils that we can find in stores are compounds to which all types of additives have been added. Oils are also very easy to apply.
The disadvantage of oils is that they require much more frequent renewals. Virtually every year.
How to apply Lasur on wood?
Before starting any task, we must pay attention to the degree of moisture in the wood. If it is too wet, above 20-25%, we should wait until it dries.
Preparation of wood. The wood must be free of impurities and traces of finishes previously applied. Sandpaper is commonly used for this. First, a coarse grain to cause greater wear, then a fine grain to obtain a smooth surface. All of this always in the sense of the wood grain.
Before the last sanding, it may be necessary to fill or seal cracks in the wood. Always respect the drying times provided by the dough manufacturer to avoid repetition of tasks.
In some woods such as iroko or elondo, which tend to ooze, or in others rich in tannins such as chestnuts, it is convenient to clean them beforehand with a solvent.
Preventive Treatment (optional). There are areas where the risk of attack by insects and fungi is greatest, requiring additional protection. For these cases, it may be interesting to apply some type of primer (usually the marks of spots offer along with the stain) that prevent the development of fungi and repels insects. Note that most stains already offer this type of protection.
Lasur Application. Can be applied by brush, roller or spray. Always towards the grain of the wood.
Usually, it is necessary to apply several layers, from 2 to 3. It is necessary to respect the drying times specified by the manufacturer, which are usually between 12 and 24 hours.
Maintenance of the woods to which the lasur was applied It’s very simple.
For day-to-day, it is enough to clean the dust and dirt that can adhere to the surface.
As for the renewal of the product, one or two coats, the same color or transparent, will suffice, unless we want to change the color. It should not be necessary to strip, scrape or sand the wood, unless there has been major deterioration.
Lasures for wood Brands
There are many manufacturers and brands of wood paint on the market, and it is common for consumers to be concerned about looking for one that guarantees a good result, not only because they do not need to repeat the work, but also because they must protect something that can represent a large investment. .
In this sense, we have added a section where we will mention some brands of lasur that normally offer a good product. Obviously, not everyone will be.
- Kaldet. This brand became popular for offering an ecological type of wood paint.