Plastic has many advantages, but it also has one significant drawback - fragility. Plastic products can crack, break, pieces can break off, etc. If the damage is significant, then it is easier to throw away the item and buy a new one than to repair it, but minor damage can be repaired with your own hands. Restoration of plastic can be carried out using different methods, the choice of which largely depends on the type of plastic itself. On many plastic products you can find markings with the composition of the plastic and this will help in choosing a restoration technology. So, thermosets are glued using a special glue, and thermoplastics are sealed. Also repair method plastic products It also depends on the nature of the damage - crack, scratch, chip, etc.
When repairing plastic items, you may need the following materials and tools: solvents (such as acetone), 1000-grit sandpaper, soldering iron or plastic glue, clamps, abrasive paste, brushes or syringe, solder, plastic cleaner, brass mesh, primer and paint for plastic, Sander, varnish
For this method you will need epoxy resin and hardener, fiberglass or sickle tape (sold in construction stores), acetone, castor oil, file and sanding paper, electrical tape or tape, plastic dishes And wooden sticks, primer for plastic, polyester putty, auto enamel.
Plastics have become a part of our lives. In many cases, plastic parts turn out to be more convenient, lighter, cheaper, and sometimes stronger than metal ones. But nothing lasts forever. Of course, a broken part is easiest to replace. And if this is not possible, it makes sense to try to repair it.
It is most often recommended to repair broken plastic parts by welding. High-quality welding produces a durable, and after appropriate processing, an almost invisible seam.
Unfortunately, welding is not always applicable. A significant part of plastics used in industry are thermosets and cannot be welded in principle. It is very difficult to weld thin plastic parts of complex shapes, which easily warp when heated. And in general, performing good welding is not easy. Just underheat it a little and the seam will become brittle; overheat it a little and the plastic of the part will begin to deteriorate.
Therefore, at home it is more appropriate to use a broken plastic part glue. Let's look at all stages of work using the example of one of the plastic parts. internal lining car interior.
The edge of the thin plastic plate through which the part was attached to the body was broken off. The thickness of the plate is about a millimeter. Welding was immediately eliminated, since when heated to the melting temperature, the thin plate would inevitably warp. Let's try to glue it together!
The plastics used to make parts are extremely diverse. Several dozen are used in industry various types plastics, each of which has its own physical and Chemical properties. Therefore, before starting repairs, you should determine the type of plastic from which the part is made.
If the size is not too small, then it is enough to inspect it carefully. Somewhere in a secluded place with inside several letters will definitely appear - part material code. The date of manufacture may be indicated next to it, and for vehicle parts, the part number according to the spare parts catalogue.
If the part is imported, then the designation will most likely be placed inside or next to the processing code - a triangle of three arrows closed on each other.
Plastic letter codes are standardized. The most common:
ABS- acrylonitrile butadiene styrene (a very widespread material, especially for large parts of external and interior decoration cars, buildings household appliances, toys)
PA- polyamide (due to wear resistance, especially with the addition of graphite, talc, fiberglass, oil, it is widely used for the manufacture of rubbing parts and gears of gearboxes)
PC- polycarbonate (a transparent polymer used in the manufacture of lenses, compact discs, headlight lenses and flashlights, also widely used cellular polycarbonate in the form of sheets with a cellular structure)
P.E.- polyethylene (packaging film, boxes, cans, garden tools, plumbing and sewer pipes, toys)
PP- polypropylene (packaging film, bags, sewer pipes, disposable tableware)
PUR- polyurethane (shoe soles, shock absorber bumpers, other elastic parts with high wear resistance)
Other symbols can be found in the complete list of technical plastic symbols according to ISO 1043-1.
Meet and combined types. For example, the part being repaired was marked ABS+PC.
A mixture of ABS plastic and polycarbonate is widely used for the manufacture of car parts, so there is no mistake.
Process engineer industrial production will say that you can glue any plastic. But he will also say that plastics are divided into three groups:
- easy to glue requiring minimal surface preparation: ABS plastic (ABS, MABS), polyacrylate (PAK), polycarbonate (PC), cellulose-based plastics (CA, CAB, CAP, CN, CP, STA), unplasticized polyvinyl chloride (PVC-U) , plastics based epoxy resin(EP)
- conditionally easy to glue, requiring minimal surface preparation and the choice of special glue or primer: some types of polyamide without fillers (PA), polystyrene (PS), plasticized polyvinyl chloride (PVC, PVC-C), polyester plastics (PEEK, PEEST, PEI, REC, PESU, PEUR )
- difficult to glue requiring special physical and chemical surface preparation: polyformaldehyde (CF, FF, MF, PF, UF), impact-resistant polystyrene (PS-HE), polypropylene (PP), polyethylene (PE), polyamides (PA)
At home, it makes sense to repair parts made of plastics of the first and, sometimes, second group. For example, polystyrene glues perfectly if you use glue based on dichloroethane or toluene (glue for plastic models).
The repaired part, made from a mixture of ABS plastic and polycarbonate, also belongs to the group of easy-to-glue parts and adheres well to almost any universal glue. IN in this case Maximum strength of the seam will be provided by EDP epoxy glue produced in Dzerzhinsk.
The glue is prepared in accordance with the instructions (10-12 parts of hardener per 100 parts of resin). It is very convenient to mix epoxy resin in a disposable polypropylene cup. Epoxy has very weak adhesion to polypropylene, so frozen residues from the glass are easily removed. And it wouldn’t be a shame to throw away such a glass either.
How to prepare surfaces for gluing?
When preparing plastic parts for gluing, it is best to follow the gluing instructions included with the adhesive. In general, preparation consists of cleaning up shallow surfaces sandpaper And degreasing organic solvent. For plastics, it is better to use ethyl alcohol, since some plastics may dissolve or swell in gasoline or acetone, which will reduce the strength of the adhesive seam.
Epoxy glue is applied in a thin layer to one or both surfaces to be glued, the parts are aligned and fixed. Unlike contact adhesives, epoxy resin does not require strong pressure; the joint can be secured by holding the parts with thread, rubber bands or clothespins. After 1-2 hours, fixing devices should be removed. Firstly, tearing them off later will be much more problematic. And secondly, the final polymerization of epoxy resin without external pressure will not allow internal stresses to form in the seam.
When gluing thin parts end to end, even the most best glue will not be able to provide sufficient strength of the adhesive connection. The fact is that the strength of the seam depends on contact areas details. In this case, the fragments of the part come into contact only along a thin fracture surface. Here it is advisable to use reinforcing pad, especially since the gluing area is not in plain sight.
If the wreckage can be found, the job becomes easier. To begin with, you should try to glue the fragments in place with any suitable glue. You can use instant cyanoacrylate adhesive “Second” or contact polyurethane “Moment”.
After this, a pattern of reinforcing lining is made from paper. Special precision is not required here, since the overlay is then processed in place.
For overlay it is best to use fiberglass, you can even foil. It is very durable and resistant material based on epoxy resin. The thickness of the lining is selected based on the size of the part; in this case, 1.5 mm is sufficient. It is convenient to cut fiberglass with a hacksaw or a cutting disc of a hand engraver. Large parts can be cut with an angle grinder (“grinder”).
The overlay is glued in the usual way with exposure for the final polymerization of the epoxy resin for at least 24 hours. The final processing of the overlay along the contour of the part is carried out with a file or engraver cutters.
The plastic part reinforced in this way is significantly stronger than the original one.
Often we need to glue a broken or cracked plastic product - from the temple of glasses to the bumper of a car. It may also be necessary to glue a hook in the bathroom or a holder for a garden sprayer. The essence of the gluing process is to dissolve the surface layer of two workpieces and form from this solution a layer of plastic common to both parts. After hardening, the parts form a single whole, or, as they say, “glue tightly together.”
In order to reliably glue plastic, you first need to find out what kind of plastic the object is made of. Knowing the plastic, you can choose the most suitable adhesive for it.
All manufacturers put recycling symbols on their plastic products - this is the well-known Recycling Triangle - a triangle with arrows on the sides, symbolizing the reuse of materials.
The triangle contains numbers from one to seven. Often the numbers are supplemented by an abbreviation. These designations are used to determine the type of plastic.
PS - polystyrene
To reliably glue plastic, you need to carefully examine the markings on the product and select an adhesive intended for polymers of this group. There is another way to determine the type of plastic - a small piece of it must be set on fire. Each type burns with a characteristic smell and type of flame. To reliably use this method at home, you need to gain considerable experience.
Tubes with glue are also marked, it’s just a pity that the designation system does not always coincide with the designations in the triangle on the plastic product. Most often you can see the following symbols on the tube:
If you are not an expert in organic chemistry, then, most likely, further study of labeling at home will not be successful. It is better to read in the user manual, which must be included with the tube, which plastics can be glued with it.
The variety of plastics used in everyday life corresponds to at least a wide variety produced compositions and methods of their use.
How to glue plastic
To dissolve the surface layer of the material, you need to destroy chemical bonds between molecules. For this purpose, special substances are used - strong solvents. Each solvent is suitable for its own group of plastics, and may not even leave a trace on a material from another group. The basis of each adhesive composition is such a solvent. In addition, the composition may include:
One of the strongest solvents is dichloroethane. It is used to glue polystyrene and plexiglass.
Depending on the method of use, the products are divided into several groups:
Liquid ones are widely used in everyday life; they are easily and simply used at home for gluing plastic that has a porous structure. They are produced both on the basis of organic solvent and water based. They are applied to surfaces that are pressed against each other for a time sufficient for the base to evaporate. After this, the adhesive layer hardens, forming a connecting seam. A typical example is PVA glue; it can be used to glue not only linoleum, but also wood at home.
Bonding takes place in two stages:
This is how Moment, BF-2 and others work. They can be used to glue polystyrene and other plastics together at home. They contain toxic substances, so you need to work in a well-ventilated area and prevent drops from coming into contact with the skin or mucous membranes.
One-component reactive agents dissolve the bonded material very quickly and harden just as quickly. These are like this famous brands, like Secunda, Superglue and their analogues. The seam is strong and rigid.
Two-component ones consist, respectively, of two components stored separately from each other:
The components are mixed immediately before use and applied to the surface, where the mixture hardens to form a compound. The basis is epoxy or polyester resins. The seam at home turns out to be very durable. Characteristic feature is that complete hardening takes quite a long time, and the seam gradually increases both strength and fragility.
This group includes substances that exhibit their properties when heated to 110-120 °C. To use, you need a special glue gun with a heating element. Differs in precision of application. In addition to plastic, it can be used to glue wood, fabric, and paper together at home.
After the type of plastic has been determined and the appropriate substance has been selected, you should:
The parts should be pressed so as to prevent their displacement in the gluing plane relative to each other.
To ensure maximum effect when gluing plastic at home, you should:
Epoxy glue produces one of the strongest bonds and is compatible with many types of plastics.
The reliability of the seam is influenced by a number of conditions. All of them are important, and failure to comply with any one can lead to the fact that what is glued at home will fall off, despite compliance with all the others. So:
Gluing plastic tightly is not so easy. Carefully following simple rules by the home craftsman will allow you to obtain strong and durable connections. The main thing is not to forget about safety precautions: do not inhale vapors of the adhesive and do not allow it to get into food, skin or mucous membranes. If accidentally swallowed, consult a doctor immediately, making sure to take the tube with you.
Plastic repair professionally in Moscow, repair time from 15 minutes.
We repair plastics of almost any brands, plastic products different shapes and configurations.
Breakage of plastic products is a fairly common problem these days. Many plastic products crack, break and become unusable during use. Plastic welding, or as this process is also called, plastic soldering, will help restore broken parts.
Soldering plastic is a process that requires careful preparation, specialist experience and a correct assessment of the repairability of the product. If you do not follow all the features of the technology, the seam will become brittle and will not withstand even minor loads.
How to repair a plastic part? There are several methods for welding. One of them is hot air rod welding. For each item being repaired, a certain welding temperature is selected, otherwise the surfaces simply will not adhere to each other. Correctly selected temperature is not the main thing in repair; you need to carefully prepare the surfaces, cut the edges in a special way and clean the surface.
There are several ways to repair a crack in plastic. To determine the technology for welding plastic, you need to know the nature of the damage and the material of the plastic. Soldering a crack in plastic can take from 1 to several hours. The process of welding a plastic product must take place in strict accordance with temperature and other factors; repairing the plastic yourself is quite problematic, there is a possibility of overheating the plastic part and making it beyond repair.
Another repair method is the extrusion method. This is the most effective technique, allowing products to continue to work hermetically and under loads. Not all products can be repaired using extrusion welding; sometimes the thickness of the material or its properties allow repairs to be carried out only using the rod method. To begin work, it is necessary to determine the material from which the part is made, then select a method of production and begin restoring the broken product. Each polymer (and there are many varieties) has its own melting point, so for repair you need to select temperature regime individually for each product.
If the question arises: how to repair a crack in plastic? - Contact us, we will be happy to help carry out repairs.
Restoration of plastic parts is carried out only by professional specialists, which guarantees full compliance with the technology. In our work we use certified material for the restoration of plastic products and parts.
Plastic is different from plastic
First, let's figure out what plastic is and what it comes in. Plastics are commonly called materials that are a combination of synthetic (less often natural) polymers with organic impurities that are added to impart various properties. finished product during its formation from a viscous-flowing state to a solid.
Depending on their response to elevated temperatures, plastics are in turn divided into thermoplastic and thermosetting. When heated, thermoplastics change from a solid to an elastic state, and this change is reversible and can be repeated many times. Thermoplastics include polyethylene, polystyrene, polycarbonate, polyvinyl chloride, polypropylene, polymethyl methacrylate and polyamide.
Polypropylene is most often used in the automotive industry: it is excellent for the manufacture of bumpers and other parts that experience various shock loads and are the most frequently damaged. Polypropylene is very elastic and is able to restore its shape with light impacts, but this is not the only good thing about it. If damaged, polypropylene parts are easy to repair because this material perfectly tolerates such a popular plastic repair method as soldering.
Thermosetting plastics have a linear structure, representing an infusible material that is destroyed as a result of heating and does not restore its original properties upon subsequent cooling. Such materials include polyurethane, polyester, urea and phenol-formaldehyde resins. The most widely used plastics in the automotive industry are those based on polyester resins. Unlike pliable polypropylene, parts made of polyester plastics have high rigidity, so this material is usually used for hoods, roofs and trunk lids. It must be remembered that when repairing such parts, using soldering is strictly unacceptable.
School repair
Restoration work on plastic parts is divided into two categories - deep structural repairs and cosmetic repairs. With a complete renovation, defects caused by damage to the structural integrity of a part or the loss of a part are eliminated, redecorating solves the problem of surface damage - eliminating chips, scratches and cracks.
A two-component polymer-captan-epoxy mixture is best suited for repairing surface defects in plastic parts. When hardened, this material not only provides the necessary strength to the repair area, but also retains elasticity. A part repaired using this mixture is able to fully restore its original properties and withstand design impact loads.
When working with propylene parts, the problem of lack of sufficient adhesion of the repair material to the surface of the plastic part being restored often arises. This is explained by the low surface energy of propylene, which leads to weak intermolecular interactions. Simply put, one material cannot stick to another. In order to increase the adhesive ability, it is necessary to use a polyolefin activator containing polyolefins in its structure (polypropylene, polyethylene, ethylene-propylene rubbers).
To restore serious damage, you cannot do without a special two-component polyurethane-based adhesive. This composition is characterized by a high polymerization rate (drying time is only 30 seconds), which allows you to glue and restore lost parts of the plastic during operation. After the shape of the lost element is restored and the composition is completely polymerized, it can be processed (drilled, sanded) and painted. When using two-component glue, you can repair not only yourself plastic element, returning it to its original presentation, but also to its fastenings. For example, this applies to bumper mounts that have received minor damage - in this case, there is no need to replace an expensive part.
The material was prepared jointly with 3M
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