Plastic repair, plastic soldering, repair of plastic parts. How to repair a broken plastic part? Glue it together! Repair plastic

To repair a plastic item yourself at home, you need to find out what kind of plastic it is made of. First of all, this depends on technical means, suitable in a particular case. A broken children's toy can sometimes be repaired using a soldering iron, and it is better to glue a radio key with a chemical solvent, a celluloid box can be restored with pear essence, and a broken carbolite ashtray can be restored with MOMENT OR BF-2 glue.

Despite the huge variety of plastics, they can be divided into two main groups: thermosetting and thermoplastic. The former cannot be softened, melted, or reshaped. In this respect, they are similar to pottery: by no means can a fired clay jug be turned into a flower pot, and vice versa, if they break, they can only be glued together. Sockets and plugs, electrical sockets, telephone housings, cameras and many other products and parts are often made from thermosetting plastic, in particular carbolite. As a rule, these products are black or Brown. Another type of thermoset plastic, aminoplasts, can be painted any color, including white. These plastics are used to make dishes, buttons, perfume boxes, clothes clips, etc.

If handled carelessly, products made from thermosetting plastics may break or crack. They can be restored using MOMENT OR BF-2 or BF-4 glue. It must be borne in mind that strong bonding will only be achieved if the pieces being joined at the fracture sites are immaculately cleaned of dust, dirt and especially grease and oil stains. Before gluing, the fracture should be thoroughly washed with warm soapy water.

The glue is applied to a completely dry surface in two thin layers. The first layer should dry enough so that the glue does not stick to your finger. Then apply a second layer, dry for 1-2 minutes and connect the pieces exactly along the break. Same as gluing wooden products, the parts must be pressed tightly together, placing them, if possible, under a press or tying them with strong twine (Fig. 1, A). At room temperature, press drying lasts 3-4 days. Do not try to speed up drying by heating the seam, for example over an electric stove, this will only delay drying as a film will form on the glue.

Rice. 1. Repair of plastic products: A - gluing products made of thermosetting plastic; B - repair of a thermoplastic plastic product using a soldering iron; B - gluing the key with a solvent.

Thermoplastic plastics, unlike thermoset plastics, soften when exposed to heat and are dissolved by certain solvents. This group includes, in particular, one of the oldest plastics - celluloid. It is used to make stationery pens, rulers, soap dishes, combs, eyeglass frames, film, toys and many other things. This plastic has considerable strength and good resistance to water, but it is extremely flammable. IN Lately celluloid (nitrocellulose) is increasingly being replaced by cellulose acetate. The latter is not flammable and at the same time is in no way inferior to nitrocellulose in other properties. Both of these plastics dissolve well in acetone.

The thermoplastic polystyrene is widely used in everyday life. It is used to make cheap and very beautiful haberdashery items, vases that look like crystal, colored toilet boxes, brooches, combs, and children's toys. It dissolves well in dichloroethane and chloroform, less so in acetone. Durable thermoplastic - polyethylene. This translucent material milky may also be painted. Due to the absolute harmlessness of polyethylene for a living organism, bottles, cups, rinsers, buckets, baby baths, etc. are made from it. Under normal conditions, it is not dissolved by organic substances.

The fact that thermoplastics melt under heat and dissolve in vigorous solvents is used in repairs. A crack in a polystyrene product can sometimes be repaired using a heated soldering iron: having connected the parts tightly, a soldering iron is drawn along the fracture line, and the plastic is “welded” (Fig. 1, B). You need to be careful to disturb the glossy, smooth surface of the product as little as possible. After welding, the seam is sanded and polished.

A broken celluloid item is glued with acetone or pear essence, wetting the fractures until the plastic softens. Then the parts are compressed and kept in this state until the solvent has completely evaporated. And if, for example, the band switch key in the radio receiver has bounced off, it is enough to drop one or two drops of dichloroethane into the hole of the key so that it sticks to the switch leg (Fig. 1, B).

By the way, a solution of thermoplastic plastic in the solvent acting on it serves good glue for a given plastic, and sometimes other materials. For example, a solution of celluloid in acetone (celluloid glue) glues not only nitrocellulose, but also paper, cardboard, wood, fabric, and leather. To prepare such glue, 1 part by weight of celluloid sawdust is dissolved in 2-3 parts of acetone. The glue must be kept in a container with a tight stopper. Celluloid can be obtained by removing the emulsion from film film. This glue is commercially known as “Hercules”.

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. Substantial part plastics used in industry are classified as 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.

How to determine the type of plastic?

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 ( packing tape, boxes, canisters, 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.

What kind of plastic can be glued?

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 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 polypropylene disposable 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 surfaces with fine 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 thin layer onto 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.

Bonding plastic parts with reinforcement

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 cutting disc 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. Final processing overlays along the contour of the part are made with a file or engraver's cutters.

The plastic part reinforced in this way is significantly stronger than the original one.

Plastic repair using an industrial hair dryer - the most optimal and reliable option. Such a weld will not be inferior in strength to any other part of the part, and if you weld another one on the inside thick layer, then you get the strongest area on the entire part.

It may seem why other methods of restoring plastic motorcycle and auto parts are needed, but everything is not so simple - you need to have the appropriate skills before undertaking repairs. Experts recommend trying to “get your hands on” some unwanted plastic with a crack before touching it directly. plastic repair motorcycle or car parts.

The first test will show that you are most likely simply deforming the part or undercooking the seam - such repair work will not bring any results. In addition to practice gets up financial issue– to carry out such work, you will need the hair dryer itself, with the ability to adjust the air supply and adjust the temperature conditions – such a product will cost about 3-5 thousand rubles + special attachments.

If such costs do not frighten the average user, then you can proceed directly to DIY plastic repair.

We select the necessary material and tools for plastic repair

For execution DIY plastic repair, you will need the following materials:

Industrial dryer. Experts recommend using models from famous brands such as Makita, Bosh, HG, etc. Read the reviews and see for yourself - these models are very practical, durable and reliable. With them you can easily repair plastic parts for several years. Some craftsmen use hair dryers for soldering radio components - they are ideal for soldering small cracks;
A set of special nozzles with a diameter of 5 to 8 mm. In most cases, they are sold separately from the hair dryer itself. Depending on the brand, they can cost from 100 to 800 rubles. For example, for the same Makita, one nozzle costs about 600-700 rubles;
Plastic for solder. It should be remembered that the plastic must be identical to the plastic of the part. You can purchase it at a specialty store or cut it yourself using old identical parts. Usually, “store-bought” solder is sold in spools - this is convenient and practical.

To repair plastic, you can use additional devices, such as:

A grinding machine will be required by the craftsman to sand the seam. It is not necessary to buy it, because sandpaper or a set of files is ideal for such purposes;
Several clamps to secure the seam. They can be purchased at any construction store.

If everything is complete, then you can safely begin the work.

Step-by-step instructions for repairing plastic

Let's consider plastic repair step by step, so that it becomes clear even to an inexperienced repairman:

Initially, you should find out the composition of the material from which the damaged part is made. Please pay special attention that the plastic of the solder must be identical to the plastic of the part being repaired. Taking this factor into account, the craftsmen set the required temperature for heating the air - if the solder does not match the part itself, one of the materials will not warm up well and will simply fall off. Or the part will overheat and the solder will “float”, which will lead to a disastrous result. The material index (marking of the plastic part) can be found by looking behind back side component being repaired. In most cases, there are three main types of plastic: PP (polypropylene parts), ABS (products made of acrylonitrile, butadiene and styrene), and finally, PA (polyamide parts);

Cleaning the part before repair work. Before you start restoration work, the crack edges of the damaged part must be carefully cleaned to get rid of protruding plastic teeth and chips. These manipulations are easy to perform using a file or sandpaper– experts recommend cleaning 5-10 mm from the edge of the fault on each side;

Assembly of the part. If the part crumbles into several separate pieces, the craftsman will have to work hard and assemble the part like a puzzle. Each individual element will have to be cleaned around the edges and installed in its rightful place. To prevent the “assembly” from falling apart, we secure the entire mosaic with clamps (similar to small clothespins). Their cost is low and they can be easily obtained at any hardware store (the price does not exceed 70 rubles per 1 piece);

Welding work. We take one rod (solder), sharpen its tip and gently press it to the edge of the cleaned fracture. As it heats up, we begin to heat the solder and plastic. When set correctly temperature conditions and the level of air supply, we begin welding work, warming up the rod and leaning it against the heated part. The stream of air will itself press the heated plastic, so you don’t need to do anything with your hands.

That's it, we have completed the repair work.

Brief summary

Now you know how to restore a plastic part yourself, without turning to specialists. After welding work All that remains is to align the protruding weld to the level of the part and that’s it. All that remains is to paint the part and install it on a motorcycle or car.

Video - do-it-yourself plastic repair

October 8, 2018
Specialization: master in construction plasterboard structures, finishing works and styling floor coverings. Installation of door and window units, finishing of facades, installation of electrical, plumbing and heating - I can give detailed advice on all types of work.

My victories

Look at the number of things that could have simply been thrown away that I saved from that fate by giving them a second chance:

glasses;
chairs;
buckets;
kitchen containers;
toys;
cabinet and refrigerator handles;
hair brushes;
hangers;
sandals;
automobile parts;
electronic cabinets;
badges and many other items.

The list is endless. So, let's find out how they can be welded, and for this I need to tell you about the soldering technique, which is suitable for most cases.

Soldering technique

In most cases you will only need:

Soldering iron. A simple flat tip used in electronics with tin solder.
Respirator. To protect the respiratory system from plastic gases (a fume hood is the best solution).

If your plastic is thin, missing a piece, or needs to be made liquid-tight or make electrical appliances safe, you may also need to:

Disposable plastic strips.
Paperclip or wire.
Superglue, solder clamps, or some other way to hold the parts in place as you weld them.

Important! Some plastics under the influence sun rays They break quite easily and collapse on their own. In these cases, welding will not help.

Preparing the soldering iron

Models with temperature controller. There are many types of soldering irons and soldering stations. In addition to the usual classic ones, there are a number of models in which you can set the desired temperature. If plastic is heated too much, it can lose its original properties, weaken and break. Also the impact high temperatures causes the formation of toxic smoke.
Flat tip models. For soldering plastic, it is best to use a flat tip. But if you don’t have one, you can flatten the existing one. This can be done by first tapping it with a hammer and then squeezing it in a vice.

I am preparing additional material

Is your plastic too thin or has holes? Then it is necessary to use plastic parts to add material to original plastic. The best option- take strips of plastic of the same type that you are welding.

But if this is not possible, the photographs above show simple solutions of this task:

cut from thin plastic parts such as shampoo bottles, pet bottles, etc.;
use plastic zippers or plastic clamps for wiring;
remove the rim from PET bottles.

Enhancing details

Although the repair process will involve very strong plastic welds, in some cases even a small constant pressure may break the repaired item again.

To avoid this:

I fasten the most loaded areas using metal staples from a construction stapler.
I solder perpendicular plastic amplifiers.
I reinforce the seams with thick wire.
I'm layering amplifiers from aluminum foil from beer cans.

Fixing the details

If there are difficulties during soldering, then it is necessary to securely fix the parts to be welded. To do this, you can use special solder clamps or superglue to temporarily hold them in place before soldering.

Protecting the respiratory system

Here are some tips to avoid the harmful effects of smoke:

Use a respirator.
Carry out soldering at head level and above (smoke will go upward, bypassing the respiratory organs).
Use any fan as an exhaust fan.
Using a soldering iron with a heat regulator, when smoke appears, reduce the temperature.
As an alternative to a soldering iron with a regulator, you can connect the plug to a voltage regulator to reduce the power and tip temperature.

Gloves and glasses:

Gloves can protect you from getting burned - some soldering irons reach temperatures of around 600°C.
Be sure to protect the lenses of your plastic glasses from accidental heat with a heat-resistant clear coating. It is best to use glasses with glass lenses.

I'm starting to solder

The secret to a successful repair is to melt the plastic where it is broken so that both melted parts fuse together, literally welding themselves together. Here's how I do it:

I place the tip of the soldering iron at the break point.
I push it forward a little to create a melted mass of plastic along the crack.
I repeat this again for the last formed piece to make another mass next to the previous one.
The result is a good weld, reminiscent of the seams formed when welding metals.

When the fixed parts are too thin or to make up for any missing part I usually add more plastic:

I place a plastic strip over the part that will be secured.
I heat it with a soldering iron until the parts to be soldered and the strip begin to melt.
I press the strip into the crack and move the soldering iron further along the welding site.
If necessary, I add metal reinforcements to make the soldering stronger. This should be done at the moment when the plastic is melted - press the metal until it enters the plastic.

Important! Be sure to check the other side to make sure the metal hasn't gone all the way through the plastic. If this happens, you will have to cover the other side with plastic.

Finishing. After making a weld, sometimes you want to refine it to make it less noticeable. To do this, I go over the top with a soldering iron, smoothing out the sagging.

Testing. First, I let the product cool, and then I start testing the welds. Good way checks - use in extreme situations, for example, sitting on a chair, and maybe jumping a little.

Here is a list of my tests recently:

The plastic box that was in some of the pictures above seemed to be quite weak. A simple fall from a low height broke it, so I had to redo the job 4 times, adding 8 metal reinforcements until the box was strong enough.
Lid for kitchen container made of PET. This damage was fixed in one go - I couldn't break it with my hands.
The PVC pipe also became very strong after it was fixed, even doing harsh tests on it.

Advice! What should I do if the seam bursts again during the test? Do the job again, but adding more metal and plastic, melt it deeper.

Cartola from instructables.com shared his experience

October 8, 2018

If you want to express gratitude, add a clarification or objection, or ask the author something - add a comment or say thank you!

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, garden wheelbarrow The cover between the frame and the container broke.

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 machine bur.

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 second glue, and we stick 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 the liquid components of 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.