MDF manufacturing technology came to our country from America thirty years after the start of industrial production of the material overseas. Slabs are not used for external work for several reasons.
In terms of resistance to dynamic and static loads, the slab does not meet the requirements of developers. It is easy to damage it, but difficult to replace.
MDF plate is used for the manufacture of furniture and sheathing of internal wall surfaces.
It is about these cases that we will talk. Painting of MDF facades will be considered for indoor use only. We will separately dwell on painting the facades of MDF furniture.
MDF boards of different shades
There is no need to list specific brands, and it is impossible to do it. We will only tell you about the varieties and brief characteristics of paints, taking into account the method of their manufacture.
The specific type must be selected taking into account the operating conditions of the MDF board, design preferences and financial capabilities. The range in price and quality is quite large, there is plenty to choose from.
|Paint type||Short performance values |
|Water based||Most popular for painting large surfaces, have satisfactory performance characteristics, are completely safe for residents. They can be white and colored, for interior and exterior work.|
|Acrylic-silicone|| Combine the advantages of acrylic and silicone paints, an environmentally friendly product.
It inhibits the reproduction of microflora and mosses, has high resistance to mechanical stress.
|Silicone||They repel water, are not afraid of moisture and exposure to high temperatures. Surfaces can be easily cleaned from dust and dirt. Due to their high elasticity, they easily compensate for the thermal expansion of MDF boards.|
|Polyvinyl acetate|| Some of the cheapest, recommended for use in rooms with minimal risk of damage.
During use, the manufacturer's recommendations should be strictly followed, otherwise delamination will appear.
|Oil||Traditional dyes, in addition to giving a beautiful appearance to surfaces, effectively protect them from moisture penetration. To improve adhesion, it is recommended to use primers.|
|Alkyd|| They have a perfectly smooth surface, made on the basis of alkyd enamels. Plastic, resistant to abrasion.
The disadvantage is that they quickly fade under the influence of direct sunlight.
Before buying paint, calculate the surface area and purchase materials with a margin. The consumption is indicated by the manufacturer. If it is recommended to cover the surface with a primer before painting, do not simplify the work. Insufficient adhesion of the paint to the MDF board causes delamination.
As a result, the need for expensive and time-consuming repairs.
Which paints are suitable for MDF
Construction paint for wood
The technology of varnishing surfaces is much more complicated than working with paints, but the effect justifies everything efforts. When choosing a particular varnish, one must take into account not only its properties and price, but also the place of application and operating conditions. The following types of varnishes can be used to cover MDF boards.
|Type of varnish||Composition and brief characteristics|
|Alcohol|| Made from ethyl alcohol and synthetic resins.
For the price, they belong to the low category, the drying time, depending on the conditions and the thickness of the layer, is 20-30 minutes.
|Alkyd-carbamide||Two-component compositions, they are distinguished by increased strength. Consist of carbamide and alkyd resins, a hardener must be added before use. They are characterized by increased strength and excellent gloss.|
|Epoxy|| Two-component, increased impact resistance, can have prolonged contact with water.
Used to cover MDF tables.
|Polyester||Resistant to aggressive chemical compounds, excellently withstand high temperatures. Multi-component polyester resin varnishes.|
|Nitrocellulose|| The composition contains resins, plasticizers and solvents. They have high water resistance, are polished, mechanical strength is average.
|Acryl-urethane||Diluted with water, safe for health, have increased adhesion to surfaces. They can be in conditions of high temperatures and humidity for a long time.|
|Polyurethane||They are produced in one-, two- and three-component. The full hardening time is up to two weeks, they are characterized by increased wear resistance, they have a high adhesion coefficient with all sawn timber.|
|Acrylic|| Odorless, non-toxic, diluted with water.
Prolonged contact with food is allowed. They have average performance in terms of performance.
Sherwin Williams Wood Classics Polyurethane Varnish
This information will help when choosing a brand of varnish, consider the maximum number of individual factors. Keep in mind that the appearance and operation time of MDF facades largely depends on the quality of the composition.
Construction varnishes for wood
Quite difficult work, requires care, skill and patience.
They are done in several stages, each of which significantly affects the final quality. Painting facades is much faster and better to do with a spray gun, if you don't have one, use high-quality brushes with soft, durable bristles.
Classic and very wear-resistant brush
The room should be at least + 20 ° C, if the individual elements of the facade are made of There is a lot of MDF, then think over the places of their drying: racks, props, etc. In most cases, after painting the plates, it is recommended to varnish them, it protects the surfaces from damage, hides small flaws, significantly improves the design look. Varnishing is a complex process that requires special tools and equipment.
We will describe below how MDF boards are varnished, but for now we will dwell on painting.
We have already told you about the criteria for choosing a paint. For furniture facades, you can only add that the color of the paint should take into account the purpose of the furniture and the intensity of its use.
Step 1. Surface preparation.
For furniture facades, in addition to cleaning from dust and degreasing surfaces, it is imperative to sand it with emery cloth No. 150-180.
Grinding MDF before painting
It is long and difficult to work by hand, and it is almost impossible to achieve the desired quality. We recommend using a professional electric reciprocating surface grinder or circular grinder.
Grinding the MDF surface
The edges are grinded with special four-sided sponges.
It is advisable to work in a respirator. When sanding, do not stop the tool in one place, it should always be in motion. One track must be covered by the next at least a third of the width. You do not need to press down on the sandpaper too much, if problem areas remain on the surface, it is better to walk over the entire area again, and not make a depression in one place.
Any grinding is accompanied by a large amount of fine dust. Take all measures to prevent it from entering adjacent rooms.
Step 2. Thoroughly remove dust from surfaces. Simple brushes are indispensable; you definitely need a powerful vacuum cleaner or compressor.
Check the condition of the parts, if there are sharp edges - remove them. The IMF does not have great strength; sharp corners will surely crumble.
Step 3 . Cover surfaces with a primer. Experienced craftsmen recommend using two types of primer, each two times.
It is possible to prime with one primer without interruption for drying, apply the first layer with horizontal movements of the spray gun, and the next one immediately with vertical movements. Adjust the amount of primer, there should be no puddles on the surface.The first primer is used to prevent further absorption of materials, and the second to improve the coefficient of adhesion between them. The second is applied only after the first primer has completely dried. Primer consumption per square meter is 80-100 grams.
Primer for MDF
Practical advice. It is very difficult for novice craftsmen to determine the consumption by eye. To get the skill, we recommend taking a small piece of MDF and weighing it on an accurate scale. Cover with a primer and immediately reweigh. Next, the area of the sample is calculated and the increase in weight is determined.
Using elementary mathematical calculations, the consumption of the primer is determined. Little - add more. Now remember how the MDF surface looks like, covered with an optimal layer, and in the future, prime with the same amount.
Application of the primer
We strongly recommend that you work only with a pneumatic spray, never achieve "factory" quality with a brush. A professional will always notice traces of villi.
Moreover, the sun's rays fall on furniture at different angles, and such lighting enhances all the disadvantages of front coverings. Prime the ends of the structures immediately.
If you need to paint the reverse side of the plate, then start work only after the front side has dried. The drying time is indicated by the manufacturer, but adjustments must be made taking into account the actual parameters of the indoor climate
It is more convenient to apply a primer with a spray
Step 4. Start sanding the soil, use special sponges.
If they are not there, take a washcloth for washing dishes, on the back side they have adhesive tape-bright. This special material, used for fine sanding, not only evens out the coating, but also leaves micro scratches on the surface, which improves the adhesion of the next coating. The movements are arbitrary in various directions. Circular movements of the sponge are not recommended, only reciprocating.
Scotch Brite Sponge
Blow or vacuum off any dust that may form on the surface. It is very convenient to work with a spray gun for another reason - it can shut off the paint supply and use it to clean surfaces from dust as a compressor.
Step 6 . Proceed with the second type of primer. It is predominantly white in color and improves the performance of the following coatings.
You also need to prime it twice, followed by sanding. Blow dust off the MDF again. The algorithm of actions is no different from the above technology.
Applying the second coat of primer
Step 7. The second coat of primer must be carefully sanded with electric sandpaper.
Do not rush, large flaws will already become noticeable on the finished product. If you have no experience with such machines, then we strongly advise you to practice on unnecessary sections of MDF.You will learn how hard to press the sandpaper to the surface, how to move it quickly, how thick the MDF is removed in one pass, etc.
Step 8. Prepare the paint.
The cooking technology is indicated by the manufacturer on the packaging.
Painting MDF panels
Painting MDF facades
Follow all recommendations. We have already mentioned that to work with a spray gun, the consistency must be more liquid. Immediately paint twice in cross directions. You should already have some practical experience in determining coating quality and paint quantity.
Paint consumption ranges from 60-180 g.
Polishing the painted surface
Painted polished MDF board
After the coating has dried, the surfaces can be varnished. This is a mandatory step for furniture interiors. Varnish not only serves as an additional and reliable protection, but also significantly improves the appearance of MDF products.
Painted MDF furniture facades
How it is done we will explain below.
But for quality, four main conditions must be observed:
You will gain experience in performing such work and the ability to use tools during priming and painting of products, it will already be much easier to work with varnish. The amount of varnish on the surface can be determined by eye, and the spray gun will "automatically" move in the right directions and at an optimal speed.
Step 1. Prepare varnish according to the instructions, consumption is approximately 100-150 g per square meter.
Open and stir the varnish
Start varnishing from the MDF ends, due to this technology it is possible to minimize the number of areas with uneven thickness. The varnish that gets a little on the front surface does not pose a threat to the final quality.
The process of applying varnish with a brush
After the first layer is dry, sand it with the finest abrasive. Professionals recommend using abrasive fiber No. 1200 according to the international classification.
It can be purchased from specialized stores.
Sandpaper # 1200
Step 2. Remove dust from the surface. Inspect surfaces from different angles in a well-lit room. Everything is fine - cover the surface with a second coat of varnish.
By the way, it is recommended to cover some facades with varnish up to 0.5 mm thick, and for this it will be necessary to increase the number of layers to five or more. At industrial enterprises, the technology is different, where the varnish is immediately poured onto the surface of the required thickness, then the sheets are fed on the conveyor to the drying chambers. At home, this technology cannot be used.
Step 3 .
Satisfactory quality - proceed with fine sanding and polishing of the finishing layer. For fine sanding use Velvet Nos. 1500, 2000 and 3000. Carefully but thoroughly treat the surface with each number, periodically remove dust.
SIA VELVET Grinding wheels
The sanding quality will improve significantly if the surfaces are slightly moistened with water. The varnish will not overheat; during work, microcracks from the action of abrasive materials do not form on the surface. Microcracks refract light rays, the surface becomes dull.
With each number, walk over the entire surface at least three to four times. The pressing force is slightly less than when sanding a primer.
Grinding takes a lot of time. If you are tired, it is better to postpone the work to the next day, and not stop completely.
Step 4. Polishing. For polishing, you need a special polishing paste and a perfectly smooth hard wheel.
There are many pastes, it is not a problem to choose. Review the recommendations and match them to your individual circumstances. Take your time, constantly monitor the condition of the surfaces for light.
If you have a large enough amount of work, we recommend purchasing special electric polishing machines. They not only speed up and facilitate work, but also significantly improve the quality.
Apply the polishing paste to the disc with a layer of about 1-2 mm, do not level it, during operation, the excess paste will independently remove from under the disc and remain on the MDF surface. Further, as required, the rotating disc itself captures the required amount of material.
As the last step, you can use polishing of surfaces with compositions that provide a mirror shine.
We mentioned that this material is not recommended for siding. But there are cases of its use for the temporary decoration of the facade walls of small old summer cottages.
This is done by those owners whose financial condition does not allow purchasing new materials; for cladding the facades of outbuildings, they use various used building materials, including MDF panels.
In order to increase the service life of structures, we recommend painting the external surfaces. Do not skip the primer, at the price the material is available to all developers, it takes a little time to carry out the work, and the effect is obvious. Select the type of primer based on the type of paint. On the packaging, the manufacturer indicates which primer should be used.
Apply the primer two times, with the brush or roller moving in perpendicular directions. If for some reason this cannot be achieved, then prime each layer at least at an angle.In addition to increasing adhesion, the primer reduces the consumption of expensive paints and prevents the appearance of stains from the base. You can paint with brushes of various sizes and rollers. But you cannot do with rollers alone, the joints must be carefully painted with brushes.
Step 1. Measure the area to be painted. Purchase paint taking into account area and consumption, do not buy paint "end-to-end", always have a stock of material. You will be more comfortable working, and the surplus will always be useful for the production of cosmetic repairs.
Standard laser rangefinder, convenient for measurements
Thoroughly clean the surface of the MDF from dust, it is advisable to use a vacuum cleaner. Dust particles can be visible on the surface of the paint; it is unrealistic to remove them later. We'll have to completely repaint the plate.
Step 3. Prepare paint and tools.
If the material has been stored in a warehouse for a long time, then the composition should be thoroughly mixed before use. When painting the surface with a spray gun, the paint will have to be slightly diluted with a solvent. Which one to choose is written on the package. To guarantee, you can first pour a small amount of paint into the solvent. If the paint curdles, the solvent is unusable.
How to thin the paint
Dilute the paint with solvent
Step 4. Soak a roller or brush in the paint and start painting the surfaces.
Paint can be applied with a brush or roller
Practical advice. Move the brush from top to bottom, so you will see drips of excess paint and eliminate them in time. If you paint the other way around, you will have to constantly return to the area previously covered with paint to eliminate drips.
You may not notice them or forget to return - a problem will arise. If the drips dry up, it will take a long time to remove. In some cases, you will have to cut them off with a blade and straighten the surface of the coating.
Step 5 . Paint the junction points with a brush, make sure that there are no traces of villi.
In the implementation, you can find low-quality paint brushes, their pile is weak. To prevent it from being left on the surface, rub the brush firmly against any clean surface before use. Insufficiently attached hairs will come out and will not create problems during dyeing.
Paint the facade
Step 6 . Let the first coat dry, time depends on the characteristics of the paint.
Professional painters do not advise drying with open windows - dust gets into the room and sticks to the paint surface.
Apply the second layer
Step 7. If the quality of one layer is unsatisfactory, apply the second. The technology is the same.
Externally painted facade
Various patterns and ornaments can be drawn while painting surfaces.
To do this, first draw the contour lines with a pencil.Each color must first be pasted over with masking tape.
Removing paintwork is not easy, much depends on its composition and your capabilities. Let's consider three ways to clean MDF surfaces.
Removal of coatings is done with a wire brush or spatula. The work is very difficult and not always effective. In this way, only very old peeled coatings can be removed, and even then not from the entire surface. It is much easier to use various electric grinders with coarse abrasive material. We warn you that there will be a lot of dust, take measures so that it does not fall into adjacent rooms.
For respiratory protection, you need to use respirators or masks. Sandpaper will clog up quickly and will have to be changed frequently.
Removing old paint with a spatula
In the photo there is a grinder, which is convenient to remove paint
Building hair dryer
Thermal paint removal method
Further, soft coatings are removed with a spatula. You need to work only on the street, some trains are very aggressive. Respiratory protection required. If necessary, the procedure is repeated several times.
Old paint thinners
Regardless of the method of removing old coatings, the MDF surface must be sanded before new painting, there will always be traces of a brush or spatula.
In addition, not all areas of the coating can be removed manually.
It is not recommended to use aerosol cans for painting furniture fronts. Their main advantage is ease of use. As for the quality of the coating, the professionals have many complaints about it.
To paint MDF wall cladding with rollers, buy them with fine nap.
Such rollers leave fewer marks, the paint lays down more evenly and has time to even out during the drying time.
Short nap roller
The longer the paint dries, the more defects it can hide on its own. Fast drying materials do not provide this advantage, the surface dries quickly and is poorly leveled.
Absolutely all MDF boards emit chemical compounds into the air. The notorious "environmental friendliness" depends only on their quantity.
In various countries, sanitary control authorities establish their own permissible standards. What is considered harmful for some, is accepted as environmentally friendly in others and allowed for use. Deep impregnation can be used to minimize the amount of harmful compounds released. This is another reason not to abandon this operation while painting MDF.
If problem areas were found on the surface after the end of the work, then they can be hidden with overhead decorative elements.
Now on sale there is a large selection of drawings on self-adhesive plastic wrap. With them, you will not only hide your marriage, but give the surfaces a beautiful exclusive look.
The pile does not rise on MDF boards, only natural wood has this drawback. When choosing paints and varnishes, pay attention to this feature. By the way, coatings that do not raise the pile during drying are much more expensive than ordinary ones, do not overpay for unnecessary properties.
Posted By: Work Style |13, Nov 2020
Posted By: Work Style |13, Nov 2020
Posted By: Work Style |01, Nov 2020
Posted By: Work Style |04, Nov 2020
Posted By: Work Style |06, Nov 2020