How to repair plastic. Plastic repair, plastic soldering, repair of plastic parts. Repair of galvanic baths made of polypropylene

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.”

Determining the type of plastic

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 reuse 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.

What does the marking on plastic mean?

PET low density polyethylene or polyethylene terephthalate. It is mainly used for packaging or packaging food products. Available in the form of film, bags or transparent containers for liquid and bulk goods, as well as drinks.
HDPE compacted low pressure polyethylene. Used for the production of shrink film and packaging bags.
V (PVC) polyvinyl chloride - non-food plastic, used for the manufacture of strong and durable items, such as household buckets, frames metal-plastic windows, linoleum.
LDPE Low Density Polyethylene high pressure. Used in the production of bottles for drinks and dairy products, packaging bags, toys, cold water pipes.
PP polypropylene. Plastic is not chemically active, heat-resistant (up to 150 ° C), most widely used in the production of medical goods, heat-resistant dishes and household utensils, toys, pipes and fittings for hot water, and much more.
PS polystyrene. Also food grade plastic, it is used to make disposable tableware, household utensils, and kitchen appliance housings. If it is foamed, it forms an excellent porous heat insulator - polystyrene foam, used in everyday life and in construction work.
O Other (others) - materials that are not intended for recycling, for example, with inclusions of metal, paper or other substances). This also includes plastics that do not belong to one of the six groups.

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.

Glue marking

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:

PC-polycarbonate (used for covering greenhouses and canopies).
ABS is an acrylonitrile copolymer.
PP polypropylene.
PPMA organic glass general purpose.
PE is a well-known polyethylene.
PVC is another familiar one - vinyl, or polyvinyl chloride.
PS – polystyrene.
PA 66 - polyamide.
PUR polyurethane.

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.

Types of adhesives

The variety of plastics used in everyday life corresponds to at least 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:

a hardener that promotes drying;
filler - dissolved molecules of the substance for which the glue is intended.

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;
contact;
reactionary;
hot melt adhesives.

Liquid

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.

Contact

Bonding takes place in two stages:

the surfaces to be glued are lubricated with a thin layer, which dissolves the surface layer of plastic, softening it and facilitating contact with another surface;
After a few minutes, the parts are pressed against each other with force, the softened layers are mixed, the solvent evaporates and a seam is formed.

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 getting on your skin or mucous membranes.

Reactionary

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:

hardener;
fixative

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.

Hot melt adhesives

This group includes substances that exhibit their properties when heated to 110-120 °C. To use you need a special glue gun with heating element. Differs in precision of application. In addition to plastic, it can be used to glue wood, fabric, and paper together at home.

How to glue plastic tightly at home

After the type of plastic has been determined and the appropriate substance has been selected, you should:

Thoroughly degrease the surfaces to be bonded. To do this, use alcohol, a degreaser or a soap solution (only laundry soap);
To glue objects more reliably, you need to increase wettability. To do this, treat the surface with a velvet file or thin sandpaper;
Mix two-component reactive substances only after completing the preparation of parts;
do not use brushes with natural bristles;
Apply enough adhesive so that when pressing the workpieces, the excess is not squeezed out beyond the gluing zone.

The parts should be pressed so as to prevent their displacement in the gluing plane relative to each other.

How to achieve maximum effect when gluing plastic parts

So that gluing plastic at home gives maximum effect, follows:

accurately determine the material and select the appropriate adhesive for it;
carefully follow the instructions for use;
wait for the required time for the seam to gain strength and do not try to use the product ahead of time;
for outdoor use or for items used in high humidity, you need to choose a waterproof brand;
despite the declared heat resistance of the adhesive, the parts themselves may not survive this temperature;
If there is no marking on the product, then you can try dropping a drop of adhesive in an inconspicuous place and see if the material dissolves.

Epoxy glue produces one of the strongest bonds and is compatible with many types of plastics.

What affects the reliability of gluing

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:

Compliance of the product material and adhesive composition.
Correspondence of the type of adhesive composition to the magnitude of the forces that the connection will experience. The direction of these efforts is equally important. Thus, compounds that produce rigid seams are not suitable for repairing, for example, shoes - after all, the sole will bend and twist during use, despite the fact that the tensile force will be small. At the same time, this composition can successfully glue, say, a hook to glass, and hang tens of kilograms on it.
Compliance with application technology. Everything is important here - how many seconds or minutes the surfaces need to be compressed, and how to degrease them, and how long to keep the parts pressed against each other. All this depends on the properties of a particular “plastic-glue” pair, is described in detail in the instructions and must be followed verbatim. A deviation of one second in the exposure time or premature start of use of the product can lead to secondary failure.
Mechanical part of the process. It is important to thoroughly clean the surface from dust and roughen it. In addition, the direction of pressing the parts against each other must be perpendicular to the surfaces being glued. You must not allow the parts to move mutually after pressing - this will also lead to failure.

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.

Necessary tool

Repairing plastic products does not require many tools:
1. A heat gun is the main working tool used to soften plastics. Hair dryer or other thermal equipment will not work, since they have insufficient power and heat flow temperature.
2. Construction knife for cutting plastics and trimming edges.
3. Steel spatula. Used to press down plastic and smooth edges.
4. A flathead screwdriver is used for the same purposes as a spatula. The screwdriver allows you to press down on small areas as needed.

Important! There is no need to use a soldering iron or any other hot object to heat the plastic.

Preparation for repair

First of all, you need to clean the product that is being repaired. I removed the gas tank and washed it a large number running water inside and outside. Also I used detergent for dishes, rags and a stiff brush to remove all dirt. I rinsed the inside until the smell of gasoline disappeared.

For final cleaning and degreasing work surface I used isopropyl alcohol. Particularly fortunate was the fact that the alcohol bottle turned out to be made of the same plastic as my gas tank. Therefore, in order to use the bottle for making patches, I had to pour the remaining alcohol into another container.

Preparing patches for repairs

In my case, the repair was complicated by the fact that the damage was at a corner, so the patch had to go around the hole on both sides. To do this, I cut out a corner element from the bottle in such a way that there was a good overlap on all sides of the hole.

You should also remove any plastic burrs or other rough edges around the damaged area to ensure the patch fits as tightly as possible.

Applying a plastic patch

The most crucial moment is uniform and correct heating of the work area and the patch. The goal is to soften the plastic and make it soft and flexible enough, but retain its shape and prevent it from spreading. It is important to follow the following rules:

Keep the gun at a distance from the heated part.
Run a heat jet over the surface of the part so that it is evenly heated over the entire area.
Plastic should not melt or flow, much less smoke or burn.

Having softened part of the patch so that the plastic began to look wet, I applied it to the repair area and began to heat it further, while simultaneously smoothing and pressing the part attached to the gas tank with a spatula. As the plastic patch warmed up and softened, I pressed it with a spatula so that it adhered tightly to the surface of the tank.
Advice! When smoothing a patch, it is important not to overdo it with force, as you can push through the softened plastic and make it even worse than it was.

When the patch is completely glued, the parts should be allowed to cool on their own without applying additional effort (do not put them in water).

Examination

After cooling, I filled the tank with water to check for leaks - everything was fine, even if I pressed on the patch area.

Finally, I want to give a few simple rules for carrying out successful repair plastic products:

For such “soldering” of plastic, you cannot use hot tools (soldering iron, etc.), as this will lead to melting of the plastic and disruption of the elasticity of the material.
The working surface and patch must be absolutely clean and free of grease.
The item being repaired and the patch must be made of the same type of plastic. This will ensure maximum efficiency repairs, since different plastics have their own temperature limit softening and fluidity.
Heating must be done gradually so that the material does not melt. If you see smoke, it means you are doing something wrong!

Pay attention! Be prepared that it may not work out the first time and you will have to apply another patch. larger size, so that it overlaps the previous one. This may also be necessary if the plastic chosen for the patch is too thin.

Manufacturers like relatively cheap, pliable and lightweight plastic. And car owners have a reason to love it - parts made from this material. This means there is no need to regularly go broke on replacing damaged parts.

Before we tell you how to repair plastic products, let's pay attention to some of their features. Today manufacturers use various types plastics, including ABS plastic, polypropylene, polyurethane, polyvinyl chloride and others. They all have different properties, soBefore starting repairs, you must find out what material you are dealing with. Marking will help you - it is on any part. Trying to weld two parts from different plastics, you will waste your time: the connection, for example, of polypropylene with ABS plastic will be fragile, and therefore extremely short-lived.

Let's get back to repairs and tell you how to repair plastic parts using glue and soldering. In front of us is a damaged spare part. Let's get started!

Solution 1: Gluing

This repair method is quite simple. For it you will need, we have - dichloroethane, it is the most affordable and perfectly glues ABS plastic. You will also need a brush, preferably a synthetic one. It is convenient because after the first use, the glued hardened hairs can be trimmed, and the rest of them can be heated, the hairs will fluff up, and the brush will still serve you.

So, take a brush, moisten it in dichloroethane, apply it to the parts or parts to be glued - first on one, then on the other. It is better to put the composition in two layers, since the first, preliminary one, will begin to actively corrode the plastic... We apply the parts to each other, press and wait. Dichloroethane takes quite a long time to dry, up to six hours. With patience, we get the whole part!

Solution 2: Soldering

In fact, there are two ways to weld a plastic part at the site of damage - using a hair dryer and a plastic rod, or a soldering iron and a brass or copper mesh. But first, let's talk about the device with which we will carry out the work.

Usually, powerful large hair dryers (also called technical hair dryers) are used for soldering. But they are inconvenient to work with: such hair dryers are bulky, heavy and heat up a large surface. That's whywe preferred simple soldering station with a soldering iron and a light compact hair dryer. It is inexpensive, around 3,000 rubles - the price may vary depending on the configuration. We will not need the solder included in the kit, which is used to repair radio components.

Method 1: Repair using a hair dryer and a wand

We remove the hair dryer from the station. We set the temperature required for soldering ABS plastic to 300 °C. As the work progresses, the temperature should be adjusted if the plastic melts too much or, conversely, not enough.

We heat the rod with a hairdryer so that it becomes soft and almost begins to melt, and we do the same with the damaged area on the part. The mating part must be well heated, otherwise the adhesion will be poor and the resulting connection will be fragile. If the plastic of the part being repaired swells, it means the process is going correctly.

Method 2. Repair using a soldering iron and mesh

To do this job, we placed a flat tip on the soldering iron. It is inconvenient to press the mesh with a standard sharp tip. Speaking of her. You can use brass or copper mesh - large or with a fine-mesh structure. A piece of brass mesh measuring approximately 250x200 mm costs about 250 rubles. A larger mesh will be cheaper and can also be used, but be prepared to spend more time.

First, let's level and fix the damaged area so that the surface does not play during the repair process. To do this, connect the edges of the crack in some places by melting them with a soldering iron and let it cool. After this, we apply the mesh and begin to solder it. We do not have a very powerful soldering iron (about 45 W), so we set maximum temperature to make the process go faster.

We begin to embed the mesh into the plastic. The result is a reinforced surface, neat and quite beautiful. This method is convenient for connecting cracks, for example. The work is easy and relatively simple. The main thing is to ensure that the mesh is completely soldered. When everything is ready, let the plastic cool. Let's check. We have a fairly strong connection. The surface moves slightly because we did not secure the parts on the outside. To get a more rigid connection, you can solder the rod here, then remove the excess plastic and paint the part.

Repairing plastic parts is a painstaking process, but relatively simple and inexpensive. In this case, you can choose the most convenient way repairs and, after spending some time, do not spend extra money.

A broken part of a tool, especially during work, can greatly spoil not only the work process itself, but also the mood for further work. It’s good if, with the breakdown of a minor part, the tool does not fail, and you can still work with it before replacing this most ill-fated part. In my case, for example, the pad between the frame and the container broke on a garden wheelbarrow.

The damage seems to be minor, and work can continue. But it's not that simple; under more or less serious load, the wheelbarrow begins to move in the direction from which the lining broke. This is very inconvenient when transporting heavy loads. Then I decided to remove the second overlay, for symmetry! I thought it would help.

It really helped - the car stopped moving to the side. But she started creaking like hell! Ears curl up! No amount of lubrication oil helps. I couldn’t stand it for a long time, and went to the nearest hardware store to get the part I needed, which, of course, wasn’t there. There was not the slightest desire to travel all over the city in search of the right thing. Then I decided to repair the broken thing myself. Today we will look at one of the options for how to put together a thin plastic lining split in half. This advice will greatly help those who find themselves in a similar situation. This may not necessarily be a wheelbarrow trim. This method can restore any plastic item or part. At least until the original one is purchased from the store.

You will need:

Pliers.
Pin.
Secondary glue.
Composite glue, type " cold welding».
A drill, as thick as a prepared pin.
Bor machine or small drill.
Small grinding disc for bur machine.

Repairing a broken part

First, you need to check whether any other small pieces have fallen off and examine the repair object in more detail. If the part being repaired has stiffening ribs, then the longitudinal ones will have to be removed. This can be done using pliers and a bur machine with a small sanding disc.

Next, in the thickest places, using a two millimeter drill, you need to drill holes inside the part. Like this:

4-5 millimeters deep. We will need these holes to reinforce the part. For greater durability. Next, we take the prepared pin, straighten it, and break it (or bite it off with wire cutters - whatever suits you!) into eight-millimeter pieces.

Now, using a match or thin wire, we lubricate the holes on the drilled half of the broken part, and stick pins made from pins into the holes.

We do everything very quickly so that the glue does not set in the empty holes. Next, we drill holes in the second half of the broken part. Strictly opposite the pins protruding from the first half. If everything turned out as it should, lubricate both halves in the split place with second glue and stick them into each other.

It is necessary to compress the parts to be glued. At least for thirty seconds so that they stick.

Now it’s the turn of the composite glue. I use the “cold welding” type - a very convenient glue. There is not as much fuss with it as, for example, with liquid components epoxy glue. Yes, and it hardens much faster, and in terms of reliability of fastening they are the same.

In general, we break off, or cut off, the piece we need from the total mass, spray our palms with water, and carefully stir and knead the glue in our palms. Until a homogeneous mass is obtained.

Next, we lubricate the inner surface of the part being repaired with second glue, the one from which we broke out the longitudinal stiffeners. And we sculpt a cold weld onto the surface greased with glue.

Plastic is different from plastic

First, let's figure out what plastic is and what it comes in. Plastics are usually called materials that are a combination of synthetic (less often natural) polymers with organic impurities that are added to give 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.

In the automotive industry, polypropylene is most often used: 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, it is strictly unacceptable to use soldering.

School of 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, cosmetic repairs 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 parts made of propylene, 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 It has 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 the plastic element itself, returning it to its original presentation, but also 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

Sometimes, in his interviews with sports publications, the former Formula 1 pilot Joachim Stuck does comparative analysis two pilots. So this time, he tried to show the difference that exists between Heidfeld and Alonso, based on his experience and observations.

So the sports analyst warns the team BMW what should they replace Nick Heidfeld, that even though the German pilot can show excellent results in racing, is not at all the one who can win the championship itself.

According to Stuck, the German team, wanting to get the title, should take on exactly Fernando Alonso, because only he is on at the moment motivated more than other pilots and even Renault this season can work wonders.