A common thing: you need to paint your bumper. Painted. And it seemed like they did everything according to technology: they applied and sanded the filler primer, then the base, varnish... They didn’t forget anything, they even degreased it conscientiously. But despite all the efforts, after some time the paint begins to “slip” off the bumper, like skin after excessive tanning. Who's to blame? Manufacturer of coatings? But no. We forgot that we are dealing with plastic, and not everything is so simple with it.
Today you will find out
Is it easy to paint plastic?
The first requirement for a paint layer applied to a plastic surface is high adhesion to this surface.
But the fact is that initially, after casting, the properties of the plastic surface do not at all contribute to strong adhesion to the future paintwork.
The greatest difficulties when painting are created by the surfaces of non-polar plastics. They have a chemically inert, non-porous surface with low surface tension - and the lower the surface energy of the plastic, the worse its “adhesion” to the applied materials. paint and varnish materials.
Among all plastics, polypropylene and polyethylene have the lowest surface energy - these plastics and their modifications are considered the most difficult to paint.
When painting other types of plastics, problems associated with adhesion are not so pronounced, but this does not make it any easier for car repair workers, since polypropylene is the most popular type of plastic used in the automotive industry. Almost all bumpers (and these are the main paintable plastic body parts) are made from various modifications of polypropylene - usually a dark gray material that can be soldered and is inert to solvents.
Try to take a polypropylene bumper and immediately apply paint on it - what will happen? Knowledgeable person will answer right away: nothing good... And indeed, the adhesive properties of the coating will be very weak. What should I do?
In the automotive industry for preliminary preparation plastic before applying paintwork materials, three main methods are most often used: treatment with corona discharge, low-temperature plasma or gas flame.
These operations are strikingly different from traditionally accepted methods of surface preparation. For example, corona discharge treatment is the effect of an electric discharge on the surface being treated, generating “jet” of plasma. Plasma processing is carried out by exposing the plastic to a plasma flow generated by a plasma torch, and flame processing is carried out by the flame of gas burners.
The purpose of this treatment is to increase the wettability of the plastic surface, thereby improving its ability to form bonds with paints. In order for the surface to be well wetted by a liquid, the surface energy of the plastic must be higher than the surface tension of this liquid. If the surface tension of the liquid (paint) is greater, it will bead up instead of uniformly wetting the surface. Therefore, all processing methods are aimed primarily at increasing the surface energy of the polymer.
Wettability. On the left is the treated surface, on the right is the untreated surface.
As a result of such processing in surface layer Changes occur in the plastic: polar molecules are formed in the previously non-polar polymer, increasing the surface energy of the material. The surface at the micro level becomes rough, and its effective adhesion area to the paint increases.
There is no need to explain how complex and expensive the equipment is used for these processing methods. Its operation is justified only in large factories, in mass production, but for car service conditions all this is too expensive and complicated. Because of this, polypropylene was considered unpaintable for a long time.
Having thought twice, chemists have developed alternative, more simple ways preparation of polymer surfaces - so-called “wet” chemical methods. The most convenient and used of them is priming the surface of the plastic. A special adhesive primer applied to the surface of the plastic serves as an effective intermediary between the polymer and subsequent coatings, and in some cases adhesion can even exceed the factory level!
Now let’s leave aside the complex chemical formulations and get down to business.
Preparing plastic parts for painting
When starting to repair a plastic part, the first step is to determine what part we had to deal with. It could be:
- new part;
- old defective coating.
New plastic elements, in turn, can be supplied with factory primer already applied or in a “pure” form.
If you can't tell whether a part is primed or not, rub a small area of the part with some rough sandpaper such as P500. If there is sanding dust, then the part is primed.
There are minimal problems with primed parts, but we'll talk about that later. Now we are interested in the procedure for working with “clean”, unprimed plastic elements.
New unprimed part
Plastic parts are made by injection molding, and special lubricants are used during the production process to ensure that the part can be correctly separated from the mold after casting. Naturally, remaining on the surface of the plastic, they do not contribute to the adhesion of the paintwork.
There are two types of such lubricants:
- external,
- internal.
External lubricants are used in diluted form and sprayed into the mold before each new production cycle. They are not always applied, but every 3-4 times, so some parts have more lubricant, others have less. All these greases can be removed in a workshop environment with a suitable degreaser.
Internal lubricants are introduced into the composition of the plastic itself, so there is no need for separate spraying into the mold. Such plastics are more difficult to paint, since they themselves are “greasy”. The same polypropylene belongs to representatives of fatty plastics. Internal lubricants do not dissolve and are not removed by water, and they can be completely removed from plastic only by heating.
But one way or another, the first step to remove dirt from the surface of the plastic should be washing.
Washing
The ideal solution in this case would be a high-pressure washer, but in the absence of one, a bucket will do just fine hot water with any active detergent(liquid soap, car shampoo) and some kind of brush or hard paint brush.
The part must be washed both outside and inside, and then rinsed with plenty of clean, warm water.
Evaporation
To be one hundred percent sure that no lubricants or dirt will interfere with the creation of strong adhesion with the future paint coating, according to the technology, the unprimed part must be heated in a chamber at a temperature of +60°C for 30-40 minutes. During this time, the lubricants located in the pores of the plastic part will rise to the surface, where we will remove them with a cloth moistened with a degreaser. This must be done promptly, while the part has not yet cooled down.
If the part has a rough textured surface or is heavily soiled (for example, an old bumper), then it is advisable to repeat the evaporation process. And then - repeat the procedure with a napkin and degreaser. For better cleaning When degreasing such parts, you can use Scotch Brite (gray).
In addition to removing lubricants, heating helps reduce internal stress in the plastic, which can subsequently cause unexpected cracking of the paintwork material. Heat treatment also helps to identify shrinkage cavities (air inclusions) and then remove them by puttying.
To save time and energy resources of the camera, you can load several plastic parts and warm them up at the same time.
In garages, it can be quite difficult to do the warm-up trick, so in such cases it is better to work with already primed parts.
Degreasing
Before the first grinding operation on plastic elements, be it preparation for priming or puttying, the surface of the part must be degreased.
In addition to the obvious goals of this operation, degreasing also helps to remove a significant portion of the static charge from the part. This is important because when applying the primer, the dust, which usually flies off the surface, will quickly stick to the “charged” plastic, as a result of which the primer will not be placed on a dry, cleaned substrate, but on an already dusty one.
For degreasing, it is advisable to use only branded degreasers, preferably special antistatic degreasers for plastics. They are not aggressive to plastic and perfectly remove static charges.
It is recommended to degrease a new plastic element both from the outside and from the inside.
Matting
To prepare a new, undamaged plastic element for priming, it is enough to matte it with Scotch Brite or a similar material. Recommended for hard plastics red(Veryfine) scotch-brite, and for soft/elastic - grey(Ultrafine).
Matting can be done both dry and with water. If a matting paste is used, after it you need to thoroughly rinse the part with plenty of warm water - the remaining paste can interfere with normal adhesion to the paintwork material, which we have so far successfully combated.
If the surface has minor damage received during transportation (for example, shallow scratches), then they are sanded using a grinder and abrasive wheels P320-P400-P500, after which the rest of the surface is treated with Scotch Brite.
After grinding, the part is degreased again.
Padding
Once and for all get rid of problems with adhesion of paints and varnishes on plastic surfaces One simple rule will help. As a primary primer on clean (unprimed) plastic, a special adhesive primer for plastic should be used (also known as a primer, adhesion activator).
As a rule, such soil is very liquid material, made on the basis of polyolefin resins, often transparent with small additions of metallic particles - to control application. The layer thickness is minimal - only a few microns. For the most part, these materials are one-component, although 2K primers are also available.
Such primers have been developed primarily for use on plastics of the polypropylene group (PP/EPDM, PPC, PPE, PPO, etc.), but most of them can also be used on other types of plastics: ABS, PA, PC, PVC, PRO, PUR, fiberglass (GFK, BMC, SMC), etc. Modern primers have virtually no restrictions on the chemical composition of plastics, with the possible exception of pure polyethylene (PE).
To improve properties and guarantee paintability, plastic body parts (fenders, hoods, bumpers, etc.) are produced in a modified form, which means they can be painted, despite the fact that they are sometimes labeled as PP and PE. In fact, unmodified polyethylenes (PE) and polypropylenes (PP) can only be dyed after activation by a gas flame or corona discharge. Otherwise, adhesion will be very weak! Made from “pure” PP or PE various tanks and other expansion tanks, disposable tableware etc.
Primers are available in both cans and aerosol cans. Aerosol primer is very convenient for minor repairs, for example, when, when sanding a bumper, small areas were sanded down to plastic. The release form in a can allows you to avoid wasting time on preparing the soil for spraying from a spray gun and on its subsequent washing. Just remember to shake the can vigorously before use.
The primer is applied in one or two thin, even layers with a wide spray over the entire surface of the part. Be careful when applying! Since the material is very liquid, one should be wary of the possible excess of the applied layer and runoff of soil (this is most possible at the ends and stiffeners, along the perimeter of the part). A significant excess of the layer thickness can cause deterioration in the adhesion of the entire coating and “compression” of subsequent applied layers.
It is also worth considering that after application the primer changes the chemical state of the substrate only for a while, during which it should be applied next material. Therefore, to achieve the best adhesion, you need to start applying subsequent layers of the system after 15-20 minutes.
Most primers can be immediately coated directly with the top enamel, but to increase protection against chipping, it is recommended to additionally apply a layer of acrylic leveling primer to the surface, not forgetting to add the required amount of plasticizer to it, depending on the hardness of the plastic.
You just need to remember that such thick layers of primer-filler, as when repairing metal parts, cannot be applied. Plastic is an elastic material, and an excessively thick layer may simply not withstand mechanical stress and the consequences of deformation.
After applying the filler - painting. Either " ", if the soil allows it, or with .
By the way, in addition to classic primers, many lines also include universal primers for plastics, combining the properties of both a primer and a filler with a plasticizer. They have good adhesion to plastic and at the same time allow you to level out minor irregularities (for example, small marks from abrasive grinding). Such primers do not require the preliminary use of an adhesion activator, and thus allow, in some cases, to save an entire layer and operation.
About epoxy primer
So, drawing an analogy with anti-corrosion primers applied to metal, which act as an effective intermediary between the surface and subsequent coatings, appropriate adhesive primers are used for this purpose on plastic.
Since we mentioned primers for metal, I would like to talk a little more about this and remember.
Those who have worked with this material know what excellent adhesive properties it has. And despite its direct purpose for application to metal, epoxy-based primer could well be used as a primary material on many types of plastics. However, there are still limitations in this not entirely logical action. The fact is that epoxy primer does not have sufficient elasticity, and a plasticizer is not used with it.
However, if you have to deal with repairing hard plastics, such as fiberglass or carbon fiber, using epoxy on these types of plastics is not only acceptable, but recommended. You can rest assured: its adhesion to the surface will be excellent!
New primed part
Practice shows that the quality of what is applied to plastic parts factory primer coating may vary greatly from case to case. There are usually no problems with original parts, but the primer on parts of dubious origin can easily have poor adhesion or increased sensitivity to solvents. It’s easy to check: take a napkin or rag soaked in solvent and apply it to the part for a minute or two.
If the coating has softened, it must either be completely removed mechanically (P150-P240-P320), or a layer of insulating primer must be applied, having previously treated the part with gray Scotch-Brite, and then painted.
If a satisfactory test result is obtained, conventional technology is used. The part is degreased, matted, degreased again and painted. For matting you can use:
- gray scotch-brite (ultrafine);
- abrasive material gradation P400-P500 (when working with a dry grinder);
- material graded P800-P1000 (when working manually “on wet”);
Before starting any work, the part must be thoroughly washed and dried, and before the matting operation, as well as after it, it must be degreased.
Damaged plastic element
By repairing a damaged plastic part we mean repair various scratches, dents, chips and similar damage to the paint layer. We will talk about more complex cases of restoring plastic parts, such as cracks or significant deformations, in a separate article.
Before starting work, a standard set of procedures is performed: the part is washed, dried and degreased. The next step is to prepare the damaged areas for puttying.
Grinding
Before you start filling damage on a plastic part, the paintwork from the surface of the defective areas should be removed - this will avoid defects such as peeling and sagging of the putty.
An eccentric sander is suitable for sanding damaged areas. abrasive wheel gradation P180.
When sanding, try to avoid excessive pressure and high speed. Remember that thermoplastics begin to melt when heated.
Puttying
Hard-to-reach areas are treated with an abrasive sponge (P600-P800) and/or gray scotch-brite (Ultrafine).
Painting plastic parts
There is no point in going into detail at this stage, since the primed surfaces of plastic and metal are absolutely identical. Just don’t forget about adding 2K paint or clear varnish required quantity plasticizer.
But it’s worth taking a closer look at plasticizers and some other additives.
Plasticizers
It is necessary to add a plasticizer to standard 2K acrylic primers, enamels and varnishes for two reasons. Firstly, the additive makes the material elastic, which means the coating will not crack when the plastic is deformed.
Secondly, when the temperature of the plastic surface changes, the paintwork will expand and contract at the same rate as it.
Have you often seen microcracks on the surface of bumper paint in places that seemed completely unaffected by deformation? This is a consequence of the thermal expansion of the material and the lack of repair materials plasticizer.
The coefficient of thermal expansion of plastics is much higher than that of metal. Cover enamels and especially primers, whose coefficient of expansion is extremely low, simply cannot withstand large temperature changes without a plasticizer and crack.
An important role is played by the amount of plasticizer added, which is always indicated in the technical documentation for the product. This amount depends on the hardness of the plastic - the harder the plastic, the less plasticizer is added. Conversely, the softer/flexible the plastic, the more.
For example, for painting an elastic bumper this amount can be 30%, for a soft polyurethane lining - 50%. When painting fiberglass, adding a plasticizer is usually not required.
No plasticizer is added to base enamels!
Mixing sequence
When adding a plasticizer, it is recommended to prepare the material in a certain sequence: first, a plasticizer is added to the base material, be it primer, enamel or varnish, and then a standard amount of hardener and, if necessary, a thinner are added to the total volume of the resulting mixture.
This sequence is due to the fact that the plasticizer also contains a binder that requires polymerization. And if a hardener is first added to the material, and then a plasticizer, this can negatively affect the drying, strength and performance characteristics of the coating.
Matting and structure additives
A well-polished varnish or top enamel has smooth surface and excellent gloss. This is very good.
However, these qualities are not always in demand. The fact is that on some cars, plastic elements may not have such a shiny appearance as the rest of the body. Moreover, they may have some texture. Often painted this way plastic bumpers SUVs, many plastic linings of Mercedes have such a granular, as if “rough” surface.
Such a surface can be imitated by special structural additives to 2K top coat enamels and clear varnishes. As a rule, they are available in two types: rude(grob) and thin(fein). As a result of using a structural additive, the paint surface becomes matte and acquires the desired degree of roughness.
When adding structural additives, additional plasticizer addition is usually not required.
There are also additives that do not change the structure of the surface, but are intended solely to reduce the gloss level of the coating. Depending on the amount added, the degree of gloss can be varied within very wide limits, allowing you to achieve different matte effects - from silky to completely matte.
Drying
To dry painted plastic, it is often recommended to use natural drying or a temperature not higher than 40-45°C. It is worth recognizing that such “reinsurance” is not without meaning. It is better to dry plastic longer than metal, but at a lower temperature. It should also be taken into account that the introduced plasticizers and other additives increase the drying time.
But still, with the right approach to repair, which we discussed in detail above, more intense heating at 60°C will not cause any problems. And the quality of the coating will only benefit from this.
Be careful with IR drying as you will not be able to control the surface temperature of plastic parts.
About adhesion after painting
Another feature of plastic is that adhesion on it does not reach its normal parameters immediately, but after a certain time. Therefore, do not be surprised if an accidental scratch on a freshly painted bumper leads to further peeling of the coating. A few days will pass and adhesion will return to normal.
For the same reasons, try not to expose a freshly painted plastic element to a washing machine. high pressure within 3-4 weeks after repair.
Utilities
Full-size versions of the images will open in a new window when you click on the image!
Procedure for repairing plastic parts
Designations of the most common plastics
Classification of plastics depending on hardness
Main modifications of polypropylene and their areas of application in automobiles
There are situations when motorists and owners of houses or apartments decide to change the usual interior and color of a room or car, as a result of which they face interest Ask: how to paint plastic and what materials can be used for this?
Painting plastic
As a rule, the technology for performing painting work for any surface remains the same. But besides general requirements, there are also some subtleties, without which it is simply impossible to perform a high-quality finish. That is why such additional information is worth taking into account.
Types of paints for PVC products
Painting plastic
Today, the market for paints and varnishes offers a huge variety of paints that can be used to properly coat PVC structures. They can be either in the form of an aerosol or spray, or in the form of conventional paint for application with a brush or roller, which can be either matte, glossy or pearlescent.
Technical characteristics of paints suitable for plastic are given in the table.
- Maraplane is a wonderful example for working on PVC structures.
Finishing work with this paint is carried out using a roller, sponge, brush or spray. If such paint on plastic is applied at a temperature of 20 o C, then after 20 minutes you can begin applying a second layer, and after another 4-5 hours the product will be absolutely ready for use. Maraplan paint is very resistant to ultraviolet rays and is also resistant to mechanical damage. But it is better not to subject the film to mechanical overload until the coating has completely dried.
- Rainbow-180 is an absolutely white glossy coating for PVC sheets.
This plastic paint is used to decorate windows, window sills, baseboards and other hard plastic, which can be used for both exterior and interior finishing. In addition to PVC, the aerosol is also suitable various surfaces, as well as putty and wood. You can work with this paint at 15-75 o C, and the next layer can be applied after 1-2 hours. This paint is great for exterior decoration.
- Snezhka is an acrylic-based enamel for decorative framing of hard PVC and other materials.
According to advice experienced craftsmen, it is better to apply this coating in 2 layers. After applying the paint, the surface of the plastic will be matte after 5-15 hours, and this coating can be used for both external and internal work.
- Acmilight is a coating that can glow blue or green in a dark room.
We paint plastic with our own hands
This paint is widely used for work on PVC, ABS, polystyrene and polypropylene. It has an increased level of strength and weather resistance. This paint has proven itself well in the restoration of pots, furniture, souvenirs, window and door blocks using a spray or by dipping from 1 to 3 layers, as indicated in the instructions for use of the material. Before starting painting work, as well as during the painting process, the paint must be thoroughly mixed all the time, because additives tend to settle, and the drying time for the finish varies between 2-4 hours.
- Gamma – acrylic paint, presented as an aerosol.
In the palette of this finishing material There are about 25 shades that can be applied to plastic, wood and steel, and it is also great as a spray for applying graffiti. Obtained in this way decorative coating will be weather resistant, have deep color and subdued shine. For achievement best result it is better to select a white base (if we are talking about a fluorescent version, this requirement is mandatory). Sometimes it is necessary to apply the material in 2 layers to increase contrast and enhance color, but reapplying the material is allowed only after 30 minutes, so that the bottom coating has time to dry properly.
It is also worth highlighting a separate category of paints that contain chromium. Chrome is also called " mirror paint» most relevant in mechanical engineering. To apply chromium to the surface of a product, both an aerosol and a galvanic method are used, the difference will be almost imperceptible.
Today, finishes such as chrome (especially in aerosol form) are becoming increasingly popular. Chrome, with its mirror-like features, captivates the eyes of passers-by, which is why motos and car enthusiasts love to use it.
In addition to high strength, chrome can withstand high temperature changes, and it does not matter whether an aerosol is used for application or whether the painting was done at the factory.
Chrome can be gold or silver in color, which can also be an interesting detail when decorating the interior of your apartment. In addition, chromium has excellent physical and chemical properties and an affordable price.
How is painting work done?
Before starting painting work, the plastic must be pre-cleaned and dried, because it is allowed to be painted only when good level adhesion, which can only be achieved on a fat-free and purified base.
To prepare the surface and clean it, under no circumstances use familiar solvents or the familiar white spirit. Today, the market offers a wide range of specialized compounds for cleaning plastic.
Please note that not every plastic needs a primer, and sometimes it happens with precision, and, on the contrary, it is impossible to do without it. To understand how to act in a specific situation, there are 2 simple test methods:
- Buoyancy
To do this check, take a piece of plastic and put it in water. If it starts to sink, you won't need primer. If, on the contrary, the material lies on the surface of the water, there will be no need for a primer.
- Combustion
If during arson the material begins to smoke, there is no need to apply a primer, but if it burns “cleanly,” applying a layer of primer is inevitable.
If you need to paint a part that is not new, it may need to be sanded, which will require sandpaper number 320-400 and water to remove cracks and cracks.
We paint plastic parts ourselves
When painting, paint is applied to the surface with brushes, paint rollers on a wool or mohair base. Aerosols and sprays can also be used for small-scale production.
Even on premium cars, plastic elements are not particularly reliable, so cases of repair and painting are much more common here than with metal elements. Who is already familiar with the procedure , he need not worry - the technology is almost the same, with the exception of some features related to chemical composition plastics In general, the appearance of both interior components and plastic exterior elements can be easily restored at home, without visiting specialized car services.
Choosing materials or how to paint plastic on your car and not regret it
If you decide to restore the appearance of plastic products, it is important to first find out the type of material. There are two types of plastics used in the automotive industry. We will not consider their chemical components here; we are only interested in the features of pre-treatment and subsequent application of paintwork.
Any do-it-yourself painting of car plastic looks like a simple operation in the video. In practice, the type of plastic is first determined by the following two criteria:
- Combustion– take a small piece from the component being repaired and set it on fire, but there should be no paint residue or dirt on it. If the flame is accompanied by black smoke and soot, then there is no need for preliminary priming (only treatment with fine abrasive sandpaper). If the plastic burns with a clean flame, then primer for the plastic is necessary.
- Buoyancy– complete immersion of a plastic part indicates that there is no need for priming; if the part remains on the surface of the water, then applying primer is indispensable.
Basic materials
Before you paint the plastic on your car, you need to take care of purchasing Supplies, which include:
- Acetone or white spirit.
- Primer for plastic (if necessary).
- Moisture-resistant sandpaper (P300 - P800).
- Paint for plastic products.
- Transparent acrylic lacquer.
Practice has already shown that when restoring paintwork on certain areas of the body, it is rational to do with spray paint. This approach is also rational in our case, because the areas to be treated are small, and purchasing a spray gun and compressor is expensive. In addition, we cannot rule out options when you cannot do without a regular paint brush.
How to dismantle plastic parts?
One of the important preliminary procedures is the careful removal of the necessary components from the interior and the outer plane of the body. The difficulty is that the options for attaching them are individual for each model, and in some cases a special tool may be needed. For example, in order to remove the dashboard on some cars, you cannot do without a pin of a special configuration.
Availability of a set universal tools will greatly simplify the painting procedure. It is important to prevent damage to the latches and loss during dismantling. small parts. For this purpose, steel forks are used, as well as polyurethane spatulas and keys for dismantling car radios and climate systems. In order not to forget the location of all elements in the future, it is recommended to take intermediate photographs of the disassembly process.
Technology for painting plastic car with your own hands at home and video of work processes
Consistency and thorough implementation of the technology for painting plastic elements guarantees the quality and durability of the paintwork. If you wish, you can familiarize yourself with the technique using the available video materials provided by the masters. Briefly, the list of works consists of the following points:
- Degreasing the surface using solvent or white spirit.
- Treat the plastic part with an antistatic agent (for example, Plak or Liqui Moly) so that when painting it does not attract dust to the surface.
- Before painting old plastic on a car, you need to eliminate defects using a special putty, which is more elastic than standard polyester.
- After drying, remove all irregularities using sandpaper. P300 – P400, and the process must be carried out using water.
- Dry the part thoroughly and degrease its surface again.
- Prime the surface in 2-3 layers, avoiding the appearance of drips.
- The dried primer should be cleaned before painting using abrasive sandpaper. P400 – P500.
- 2-3 layers of acrylic paint with plasticizing additives are applied to the cleaned surface, each layer needs to dry for 15-25 minutes.
- After final drying, a layer of varnish is applied.
- Polish the finished surface of the paintwork with polishing pastes.
Methodology has already been worked out for a long time, to perform it it is advisable to have a grinder and appropriate accessories. But if necessary small areas It is quite possible to process it manually.
Using a brush when painting plastic car parts
It happens that painting with a brush looks more convenient and profitable than using a can of aerosol paint. You won’t see this method of painting the standard plastic of a car with your own hands in the video. However, this does not mean that you should not pay attention to it; on the contrary, it guarantees high-quality adhesion and good coverage small fragments. However, when working, a number of features should be taken into account:
- Paint applied with a brush takes longer to dry, so the drying time should be increased by 15-20 minutes.
- When painting, you should try to ensure a minimum layer thickness. To do this, during the process, the brush should be pressed well to the surface and work quickly.
- Carefully wipe off excess paint on the edge of the can.
- When working, maintain the same painting angle.
On a note
Do not forget that nitro enamel from cans contains an aggressive solvent. If you apply a thick layer of such paint, the plastic may dissolve, not the entire part, of course, but the surface - very likely.
To prevent this result, it is better to use a special primer. In addition, you should not allow a subsequent layer of paint to be applied without the previous one completely drying.
What do you need to color plastic at home?
How to paint plastic at home?
Step-by-step instructions for painting plastic
Step_1 Clean the plastic surface from dirt using a sponge (brush) and soapy water. If dust and dirt remain on the product, the paint will not apply evenly and the product will have to be repainted. Heavy soiling, mold and erosion can be cleaned with bleach. Before starting work, dry the plastic product thoroughly.
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Step_2 To degrease the surface, wipe it with solvent or white spirit, then rinse off the applied composition and dry the product thoroughly. Step_3 To create a porous structure, sand the surface with fine sandpaper or special grinder. Sanding will allow the paint to lie perfectly flat, due to the bonding of the paint and the porosity of the surface. After sanding, the surface will become matte. Properly selected sandpaper will not give the product unwanted roughness, so sandpaper It is better to choose a grit of no more than 180. Be sure to remove dust from sanding. |
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Step_4 Before painting the plastic at home, cover the areas that are not to be painted with construction tape and remove it immediately after finishing the work.
Step_5 Now you can start painting the plastic with spray paint. Shake the spray in the can for at least 30 seconds, spray the aerosol paint from a distance of 20-30 cm from the surface. You need to apply the paint with smooth, even movements. After the first layer has dried, which will take 15-20 minutes, apply subsequent layers of paint. When painting plastic, it is recommended to apply at least 2 - 3 layers of paint.
Step_6 After the spray paint has dried, apply the varnish in the same way and wait for it to dry. Complete (final) drying takes no less than 2 - 2.5 hours. The product is ready to use!
What to pay attention to when painting plastic?
As we have already said, there are different types of plastic, so it is recommended to carefully choose the paint. Ideally, you need to use special paint for plastic.
5 In addition, please note that for aerosol paints in cans there are special tips for convenient regulation of the amount of paint sprayed and its uniform distribution
We talked about the simplest and effective way painting plastic at home using aerosol paints, however, this procedure can also be carried out with a regular brush using canned paint.
How to paint plastic at home with a brush?
Painting plastic items using a brush is somewhat different from the method described above and has its advantages and disadvantages. One of the features is considered long term drying, which means that the product must be completely isolated from dust on the newly painted surface, which is not so easy at home. This is why the brush painting method is used to paint objects that do not require special attention. The technology for painting plastic with a brush at home is quite simple and essentially repeats the process of working with aerosol paint:
Step_5 This is an optional step. If you want to further protect the painted surface, you can apply acrylic varnish. Apply varnish ONLY to completely dry paint. In the case of aerosols, we know that the paint dries in 15-20 minutes, but here everything will depend on what kind of paint you use. Varnish drying time 2 - 2.5 hours
What should you pay attention to when applying paint to plastic with a brush?
1 Apply paint in a thin layer, constantly pressing the brush to the surface
2 When taking paint onto a brush, do not immerse the brush completely in the paint.
3 Take into account the painting angle - it should be the same.
4 For even coverage, apply the paint in wide stripes so that the paint fills the pores, and then carefully blend the applied layer.
So, we talked in detail about how and with what to paint plastic at home. You can safely start painting and make sure from experience that it is not at all difficult, and the result is worth the time and effort!
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Most home craftsmen think that painting plastic parts with their own hands is a fairly simple task. However, not all types of this material are equally suitable for this. Of course, it is possible to paint these surfaces, and the material will lie on them quite evenly, but the service life of the coating will be short.
Once dry, the paint will begin to peel, crack, and peel.
Below we will try to give advice on:
- what kind of plastic can be painted at home;
- how to do it correctly;
- how to paint plastic.
What you need to know about plastic
This product happens different types, and each of them has its own unique properties. Therefore, the coloring process is different for everyone, sometimes radically different. By the way, in your work you may encounter plastics that cannot be painted.
An example would be products made of polyethylene (PE) or polypropylene or polyethylene, from the surfaces of which the paint will peel off in layers. Therefore, it is almost impossible to paint metal-plastic pipes made from polyethylene. So it’s better to immediately select the desired shade.
Automotive plastics can be divided into two types:
- require ;
- not required.
Tip: before completely erasing the paint from the plastic, experiment with the solvent on a small area of the surface.
Before painting, it is necessary to determine the type of material as follows:
- Dip a small piece of the product or its entirety into the water:
- if it goes under water, then there is no need to prime the part;
- if it remains on the surface, therefore, the material requires the application of a special primer mixture for plastic.
- The next option is to set fire to a piece of plastic part that has been cleared of dirt and paint:
- will burn with black smoke and soot, which means you can do without applying a primer;
- the flame is even and clean, therefore, it is necessary to prime its surface.
How to paint plastic
Below is suggested detailed instructions which will help you understand this process. Try to stick to it to get the final coverage you want.
Plastic painting consists of several stages:
- Degreasing surfaces with special compounds.
- Application of primer.
- Applying an acrylic-based primer.
- Sanding acrylic primer.
- Surface painting.
Features of coloring plastic products
- PVC or ABS plastics can be painted, but they must first be treated with a primer to increase adhesion (sticking). You can buy them in auto stores, where they are sold under the name “primer for plastic,” or in stores that sell paint and varnish materials, for example, Otex-type primers from the Tikkurila company. These compounds can be applied by wiping the surface or spraying it, after which you need to wait until they dry, usually 1-2 minutes.
- Make sure that the surfaces of the prepared surfaces are free of dirt and oil, and that they are dry..
Advice: you don’t have to carry out additional preparation of surfaces for painting if you are working with ABS plastics or polystyrene, on which acrylic paint will be applied on water based.
- It is desirable that the temperature of plastic products, paint and painting equipment be the same. Ideal conditions can be considered when the room temperature is from 18˚C and the humidity does not exceed 80%.
- Paint in one layer, the thickness of which should be about 60 microns. With a smaller parameter finishing coat may seem fragile and the paint will not last long on the surface of the product. At the same time, with a thick layer (more than 120 microns), the drying time will increase, which often has a bad effect on appearance coverings.
- Dry the plastic after painting at a temperature of 18-60˚C, this depends mainly on the thickness of the applied layer. For example, with a thickness of 90-120 microns, drying at a temperature of 50˚C and a humidity of 65% can last about 3 hours. Polypropylenes and polyamides can be dried at a temperature of 100˚C in 20 minutes.
- The paint on plastic surfaces dries completely (polymerizes) in 5-7 days, but when temperature regime low, high humidity and a thick layer of paint, this time period can increase several times.
Aerosol paint
This is one of the most convenient. The capacity of the can is 400 mm, which is enough to paint windows, slopes and small parts. Due to the wide variety of ready-made shades, this method is increasingly used in home repairs, although their price is more expensive than similar compositions in jars.
Advice: you don’t need to think about how to remove paint from water-based plastic - treat it with plain water, but you need to hurry, otherwise the process will become much more complicated after drying.
Most often, an acrylic universal composition is used, which dries quickly, thanks to which it is possible to transform the interior of a room in a short time. Lifetime spray paint exceeds three years.
Its convenience when applied to the selected surface also plays an important role. You do not need any additional tools for this, and you do not need to have any special professional skills. The layer under pressure is applied evenly to the plastic.
Advice: before you start work, you need to make sure that the room is well ventilated; it is best to open the windows for this. In addition, it is necessary to adhere to basic safety precautions - protect your eyes with special glasses and your respiratory organs with a paint respirator.
Conclusion
Applying paint to plastic products has its own peculiarity associated with the surface property. Before starting work, you should determine its characteristics and select the appropriate materials for the process. The video in this article will help you find additional information on this topic.
