In this guide, I'll show you how to melt plastic at home. Remelting plastic bottles high density polyethylene (HDPE) and making blocks from them that can be used in a variety of ways.
We use and throw away a lot of plastic bottles every day ... Let's change that!
Dave Hackens is an amazing guy who has done a lot of videos about plastic recycling. He shows you how to collect, melt and process plastic items to create new things. However, if you just want to try recycling a few bottles, follow this quick guide.
Step 1: materials and tools
MATERIALS:
- High Density Polyethylene (HDPE) Bottles
- Wooden planks (for making a mold)
TOOLS:
- clamps
- baking paper
- gloves with thermal protection
- scissors / knife
Step 2: Form
It is not necessary to make a very complex mold for melting plastic.
Since we are going to melt the plastic into a regular block, we need a simple box. The more accurately and accurately the box is assembled, the more accurate and accurate the block will be.
As you can see from the above pictures, I used wood planks that were in my workshop, and I also covered each inner surface of the box with baking paper. This will be important later when we retrieve the block from the form. Wood is a porous material and molten plastic is very sticky, so don't touch them.
Step 3: How to cut the bottles
First of all, HDPE, what is it? How can you tell it apart from all other types of plastic?
HDPE - High Density Polyethylene. It is a fairly common material used specifically for the production of plastic bottles and corrosion-resistant piping.
As you can see in picture # 1, it can be easily distinguished from other types of plastic thanks to the number “2” as the resin identification code.
After removing the labels and washing the bottles, we need to cut them into small pieces. Less is better as it takes less time to melt. Use a knife or sturdy scissors.
I usually start with the knife, cut off the neck (photo # 2), which is the harder part, then cut off the base and finally the handle.
Then you can use scissors to make smaller pieces out of larger pieces (photo # 4).
Step 4: melting
Each type of plastic has a different melting point.
Dave Hackens has done a great job with each type to customize the correct melting point ().
I found out that in my oven, HDPE usually melts at around 180 ° C.
While the oven is heating, place a piece of baking paper on a baking sheet and place the pieces of plastic on top of it. Finally, place the baking sheet in the oven and check it every 10 minutes.
Step 5: marble effect
The first paint I'll show you is my favorite: the marble effect.
After 10/15 minutes, if you see the plastic looking sticky, you can remove it from the oven. Put on heat-resistant gloves and roll the plastic (Photo # 2/3).
Act quickly (the plastic cools down), but keep in mind that it is very hot and sticky.
Once you have something like what you can see in photo # 4, you can put it back in the oven.
WARNING: Use gloves! If plastic gets on your skin, immediately rinse the affected area with cold water to relieve pain.
Step 6: fix the shape
After 10 minutes, remove the plastic from the oven and place it in the mold. Clamp it as tightly as you can, and every 5 minutes, tighten the clamps harder. HDPE shrinks as it cools, so you must tighten the clamps frequently to get a flat block.
Step 7: marble block
This is the result after 2 hours of refrigeration.
As you can see from the photo, thanks to the torsion-rotational motion technique that we used, we got a wonderful marble effect. I really like this method because you can see all the colors used.
Step 8: camouflage effect
Here's another coloring. I call it the camouflage effect.
It is easier and safer than the marble effect because there is no need to touch the plastic with your hands. As in Step 5, after 10/15 minutes, if you see the plastic looking sticky, you can remove it from the oven.
This time we will be using the folding technique. Very carefully (and always use gloves), lift the baking paper on one side and fold the plastic over you (photo # 2).
Repeat on the other side and place back in the oven.
Step 9: fix the shape
After 10 minutes of melting, remove the plastic from the oven, fold into last time by making something like an egg roll (photo # 1) and place it in the mold.
As in step 6, pinch it as hard as you can and return every 5 minutes to tighten the clamps. Then leave it to cool for a couple of hours.
Step 10: camouflage block
Here is the result. Looks really like camouflage.
In modern cars, the proportion of plastic parts is constantly growing. The number of repairs on plastic surfaces is also growing; more and more often we are faced with the need to paint them.
In many ways, the color of plastics differs from the color of metal surfaces, which is primarily due to the very properties of plastics: they are more elastic and have less adhesion to paintwork materials. And since the spectrum polymer materials used in the automotive industry is very diverse, then there should not be some universal repair materials that can create high-quality decorative coating on many of their types, painters would probably have to get a special education in chemistry.
Fortunately, everything will actually turn out to be much easier and immerse yourself in the study. molecular chemistry we don't need polymers. But still, some information about the types of plastics and their properties, if only for the purpose of broadening one's horizons, will be clearly useful.
Today you will find out
Plastics - to the masses
In the 20th century, mankind went through a synthetic revolution, new materials - plastics - entered its life. Plastic can be safely considered one of the main discoveries of mankind; without its invention, many other discoveries would have been obtained much later, or they would not have been at all.
The first plastic was invented in 1855 by the British metallurgist and inventor Alexander Parks. When he decided to find a cheap substitute for the expensive ivory, from which billiard balls were made at that time, he could hardly imagine the significance of the product he received later.
The ingredients of the future discovery were nitrocellulose, camphor and alcohol. A mixture of these components was heated to a fluid state, and then poured into a mold and solidified at normal temperature. This is how Parkesin was born - the progenitor of modern plastics.
From natural and chemically modified natural materials the development of plastics came to fully synthetic molecules a little later - when a professor at the University of Freiburg German Hermann Staudinger discovered a macromolecule - that "brick" from which all synthetic (and natural) organic materials... This discovery earned the 72-year-old professor the Nobel Prize in 1953.
Since then, everything has begun ... Almost every year, there were reports from chemical laboratories about the next synthetic material with new, unprecedented properties, and today in the world millions of tons of all kinds of plastics are produced annually, without which life modern man absolutely unthinkable.
Plastics are used wherever possible: in ensuring the comfortable life of people, agriculture, in all areas of industry. The automotive industry is no exception, where plastic is used more and more, irrepressibly displacing its main competitor, metal.
Compared to metals, plastics are very young materials. Their history is less than 200 years old, while tin, lead and iron were familiar to mankind in ancient times - 3000-4000 years BC. NS. But despite this, polymeric materials by a number of indicators are significantly superior to their main technological competitor.
The advantages of plastics
The advantages of plastics over metals are obvious.
First, plastic is much lighter. This allows you to reduce total weight vehicle and air resistance when driving, and thereby - to reduce fuel consumption and, as a result, exhaust emissions.
The overall reduction in vehicle weight by 100 kg due to the use of plastic parts saves up to one liter of fuel per 100 km.
Secondly, the use of plastics gives almost unlimited possibilities for shaping, allowing you to embody any design ideas into reality and get details of the most complex and ingenious shapes.
The advantages of plastics also include their high corrosion resistance, resistance to weathering, acids, alkalis and other aggressive chemical products, excellent electrical and thermal insulation properties, high coefficient noise suppression ... In a word, it is not surprising why polymer materials are so widely used in the automotive industry.
Have any attempts been made to create completely plastic car? But how! Just remember the notorious Trabant, produced in Germany over 40 years ago at the Zwick-Kau plant - its body was entirely made of laminated plastic.
To obtain this plastic, 65 layers of very thin cotton fabric (supplied to the plant from textile factories), alternating with layers of ground cresol-formaldehyde resin, were pressed into a very strong material 4 mm thick at a pressure of 40 atm. and a temperature of 160 ° C for 10 minutes.
Until now, the bodies of the GDR "Trabants", about which they sang songs, told legends (but more often they composed jokes), lie in many landfills in the country. They lie ... but they don't rust!
Trabant. The world's most popular plastic car
Jokes as a joke, and there are still promising developments of all-plastic bodies of serial cars, many bodies of sports cars are entirely made of plastic. Traditionally metal parts(hoods, fenders) on many cars are now also replaced with plastic ones, for example, in Citroën, Renault, Peugeot and others.
But unlike the body panels of the popular "Trabi", plastic parts modern cars no longer cause an ironic smile. On the contrary, their resistance to shock loads, the ability of deformed areas to self-repair, the highest anti-corrosion resistance and low specific gravity make you feel deep respect for this material.
Concluding the conversation about the advantages of plastics, one cannot fail to note the fact that, although with some reservations, still most of them lend themselves well to coloring. If the gray polymer mass did not have such an opportunity, it would hardly have gained such popularity.
Why paint plastic?
The need to color plastics is due, on the one hand, to aesthetic considerations, and on the other hand, to the need to protect the plastics. After all, nothing is eternal. Although plastics do not rot, but during operation and exposure to atmospheric influences, they still undergo aging and destruction processes. And the applied paint and varnish layer protects the plastic surface from various aggressive influences and, therefore, prolongs its service life.
If it is very easy to paint plastic surfaces under production conditions - in this case we are talking about a large number new identical parts made of the same plastic (and there are their own technologies), then a painter in an auto repair shop is faced with the problems of heterogeneity of materials of various parts.
This is where you have to answer the question: “What is plastic in general? What is it made of, what are its properties and main types? "
What is plastic?
In accordance with the domestic state standard:
Plastics are materials, the main part of which are such high molecular weight organic compounds that are formed as a result of synthesis or transformations of natural products. When processed under certain conditions, they tend to exhibit plasticity and formability or
deformation.
If from such a difficult description, even for reading, and not only for understanding, the description is removed from the first word "plastics", perhaps, hardly anyone will guess what it is all about. Well, let's try to figure it out a little.
"Plastics" or "plastics" were so named because these materials are capable of softening when heated, becoming plastic, and then under pressure they can be given a certain shape, which is retained upon further cooling and hardening.
The basis of any plastic is (the same "high molecular weight organic compound" from the definition above).
The word polymer comes from the Greek words poly (many) and meros (parts or links). This is a substance whose molecules consist of a large number of identical, interconnected links. These links are called monomers("Mono" is one).
This, for example, looks like a polypropylene monomer, the most commonly used type of plastic in the automotive industry:
The molecular chains of a polymer are made up of an almost infinite number of such pieces, connected into a single whole.
Polypropylene molecule chains
By origin, all polymers are divided into synthetic and natural... Natural polymers form the basis of all animal and plant organisms. These include polysaccharides (cellulose, starch), proteins, nucleic acids, natural rubber and other substances.
Although modified natural polymers find industrial applications, most plastics are synthetic.
Synthetic polymers are prepared by chemical synthesis from the corresponding monomers.
Oil is usually used as a feedstock, natural gas or coal. As a result of a chemical reaction of polymerization (or polycondensation), many of the "small" monomers of the starting material are joined together, like beads on a string, into "huge" polymer molecules, which are then molded, cast, pressed or spun into a finished product.
So, for example, polypropylene plastic is obtained from combustible propylene gas, from which bumpers are made:
Now you have probably guessed where the names of plastics come from. The prefix "poly-" ("many") is added to the name of the monomer: ethylene → polyethylene, propylene → polypropylene, vinyl chloride → polyvinyl chloride etc.
International plastics abbreviations are abbreviations for their chemical names. For example, polyvinyl chloride is denoted as PVC(Polyvinyl chloride), polyethylene - PE(Polyethylene), polypropylene - PP(Polypropylene).
In addition to the polymer (it is also called a binder), the composition of plastics can include various fillers, plasticizers, stabilizers, dyes and other substances that provide plastic with certain technological and consumer properties, for example, fluidity, plasticity, density, strength, durability, etc.
Types of plastics
Plastics are classified according to various criteria: chemical composition, fat content, hardness. But the main criterion that explains the nature of the polymer is the nature of the behavior of the plastic when heated. On this basis, all plastics are divided into three main groups:
- thermoplastics;
- thermosets;
- elastomers.
Belonging to a particular group is determined by the shape, size and location of macromolecules, along with the chemical composition.
Thermoplastics (thermoplastic polymers, plastomers)
Thermoplastics are plastics that melt when heated and return to their original state when cooled.
These plastics are composed of linear or slightly branched molecular chains. At low temperatures, the molecules are located tightly next to each other and almost do not move, therefore, under these conditions, the plastic is hard and brittle. With a slight increase in temperature, the molecules begin to move, the bond between them weakens and the plastic becomes plastic. If you heat the plastic even more, the intermolecular bonds become even weaker and the molecules begin to slide relative to each other - the material passes into an elastic, viscous-flow state. With decreasing temperature and cooling, the whole process goes in reverse order.
If overheating is avoided, in which the chains of molecules break down and the material decomposes, the heating and cooling process can be repeated as many times as you like.
This feature of thermoplastics softening many times allows you to repeatedly process these plastics into certain products. That is, theoretically, one wing can be made from several thousand yogurt cups. In terms of protection the environment this is very important because subsequent processing or disposal - a big problem polymers. Once in the soil, plastic products decompose within 100-400 years!
In addition, due to these properties, thermoplastics lend themselves well to welding and soldering. Cracks, fractures and deformations can be easily repaired by heat.
Most of the polymers used in the automotive industry are thermoplastics. They are used for the production of various parts of the interior and exterior of the car: panels, frames, bumpers, radiator grilles, lamp housings and exterior mirrors, wheel covers, etc.
Thermoplastics include polypropylene (PP), polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene copolymers (ABS), polystyrene (PS), polyvinyl acetate (PVA), polyethylene (PE), polymethyl methacrylate (plexiglass) (PMMA), polyamide (PA) , polycarbonate (PC), polyoxymethylene (POM) and others.
Reactoplastics (thermosetting plastics, duroplastics)
If for thermoplastics the process of softening and hardening can be repeated many times, then the thermosetting plastics after a single heating (during the molding of the product) pass into an insoluble solid state, and do not soften with repeated heating. Irreversible curing occurs.
In the initial state, thermosetting plastics have a linear structure of macromolecules, but when heated during the production of a molded article, the macromolecules are "crosslinked", creating a lattice spatial structure. It is thanks to this structure of closely linked, "cross-linked" molecules that the material turns out to be solid and inelastic, and loses its ability to re-enter a viscous-flow state.
Because of this feature, thermosetting plastics cannot be recycled. Also, they cannot be welded and molded in a heated state - when overheated, the molecular chains disintegrate and the material collapses.
These materials are sufficiently heat-resistant, so they are used, for example, for the production of crankcase parts in the engine compartment. Large-size external body parts (hoods, fenders, trunk lids) are produced from reinforced (for example, fiberglass) thermosets.
The group of thermosets includes materials based on phenol-formaldehyde (PF), urea-formaldehyde (UF), epoxy (EP) and polyester resins.
Elastomers are plastics with highly elastic properties. When exposed to force, they show flexibility, and after stress relief, they return to their original shape. Elastomers differ from other elastic plastics in their ability to maintain their elasticity over a wide temperature range. So, for example, silicone rubber remains elastic in the temperature range from -60 to +250 ° C.
Elastomers, like thermosets, consist of spatially reticulated macromolecules. Only unlike thermosets, elastomer macromolecules are located more widely. It is this placement that determines their elastic properties.
Due to their reticular structure, elastomers are infusible and insoluble, like thermosets, but they swell (thermosets do not swell).
The elastomer group includes various rubbers, polyurethane and silicones. In the automotive industry, they are used primarily for the manufacture of tires, seals, spoilers, etc.
All three types of plastics are used in the automotive industry. Also available are blends of all three types of polymers - the so-called "blends" (blends), the properties of which depend on the ratio of the mixture and the type of components.
Determination of the type of plastic. Marking
Any repair to a plastic part must begin by identifying the type of plastic from which the part is made. If in the past this was not always easy, now it is easy to "identify" plastic - all parts are usually marked.
Manufacturers usually stamp the designation of the plastic type with inside parts, be it bumper or cover mobile phone... The type of plastic is usually enclosed in characteristic brackets and may look like this:> PP / EPDM<, >PUR<,
Control task: remove the cover of your mobile phone and see what type of plastic it is made of. Most often it is> PC<.
There can be many options for such abbreviations. We will not be able to consider everything (and there is no need for that), so we will focus on several types of plastics most common in the automotive industry.
Examples of the most common types of plastic used in the automotive industry
Polypropylene - PP, modified polypropylene - PP / EPDM
The most common type of plastic in the automotive industry. In most cases, when repairing damaged or painting new parts, we will have to deal precisely with various modifications of polypropylene.
Polypropylene has, perhaps, a combination of all the advantages that plastics can have: low density (0.90 g / cm³ - the lowest value for all plastics), high mechanical strength, chemical resistance (resistant to diluted acids and most alkalis, detergents, oils, solvents), heat resistance (begins to soften at 140 ° C, melting point 175 ° C). It hardly undergoes stress corrosion cracking and has good recovery properties. In addition, polypropylene is an environmentally friendly material.
The characteristics of polypropylene make it an ideal material for the automotive industry. For his such valuable properties, he even received the title of "king of plastics".
Almost all bumpers are made on the basis of polypropylene, and this material is also used in the manufacture of spoilers, interior parts, dashboards, expansion tanks, radiator grilles, air ducts, housings and battery covers, etc. In everyday life, even suitcases are made of polypropylene.
When casting most of the above parts, not pure polypropylene is used, but its various modifications.
"Pure" unmodified polypropylene is very sensitive to ultraviolet radiation and oxygen, it quickly loses its properties and becomes brittle during use. For the same reason, paint and varnish coatings applied to it cannot have durable adhesion.
The additives introduced into polypropylene - more often in the form of rubber and talc - significantly improve its properties and make it possible to paint it.
Only modified polypropylene can be dyed. On "pure" polypropylene, the adhesion will be very weak! Pure polypropylene> PP< изготавливают бачки омывателей, расширительные емкости, одноразовую посуду, стаканчики и т.д.
Any modifications of polypropylene, no matter how long the abbreviation of its marking, is indicated by the first two letters anyway, as> PP ...<. Наиболее распространенный продукт этих модификаций — >PP / EPDM< (сополимер полипропилена и этиленпропиленового каучука).
ABS (copolymer of acrylonitrile, butadiene and styrene)
ABS is elastic, but at the same time impact-resistant plastic. The component of rubber (butadiene) is responsible for elasticity, acrylonitrile is responsible for strength. This plastic is sensitive to ultraviolet radiation - under its influence the plastic ages quickly. Therefore, ABS products cannot be kept in the light for a long time and must be painted.
It is most commonly used in the production of lamp housings and exterior mirrors, radiator grilles, dashboard liners, door trims, wheel caps, rear spoilers, etc.
Polycarbonate - PC
One of the most impact-resistant thermoplastics. To understand how durable polycarbonate is, the fact that this material is used in the manufacture of bulletproof bank racks is enough.
In addition to strength, polycarbonates are characterized by lightness, resistance to light aging and temperature extremes, and fire safety (this is a difficult-to-ignite, self-extinguishing material).
Unfortunately, polycarbonates are quite sensitive to solvents and tend to crack under the influence of internal stress.
Unsuitable aggressive solvents can seriously impair the strength characteristics of plastic, therefore, when painting parts where strength is of paramount importance (for example, a motorcycle helmet made of polycarbonate), you need to be especially careful and strictly follow the manufacturer's recommendations, and sometimes even fundamentally refuse to paint. But spoilers, radiator grilles and polycarbonate bumper panels can be painted without problems.
Polyamides - PA
Polyamides are tough, durable and elastic materials. Parts made of polyamide can withstand loads close to the loads permissible for non-ferrous metals and alloys. Polyamide has high wear and chemical resistance. It is almost immune to most organic solvents.
Most often, polyamides are used for the production of removable car caps, various bushings and liners, pipe clamps, door lock tongues and latches.
Polyurethane - PU, PUR
Before the widespread introduction of polypropylene in the production, polyurethane was the most popular material for the manufacture of various elastic car parts: steering wheels, mud covers, pedal covers, soft door handles, spoilers, etc.
Many people associate this type of plastic with the Mercedes brand. Bumpers, side door strips, sills on almost all models were made of polyurethane until recently.
The production of parts from this type of plastic requires less sophisticated equipment than polypropylene. Currently, many private companies, both abroad and in the countries of the former Soviet Union, prefer to work with this type of plastic for the manufacture of all kinds of parts for car tuning.
Fiberglass - SMC, BMC, UP-GF
Fiberglass plastics are one of the most important representatives of the so-called "reinforced plastics". They are made on the basis of epoxy or polyester resins (these are thermosets) with fiberglass as a filler.
High physical and mechanical properties, as well as resistance to the effects of various aggressive media have determined the widespread use of these materials in many areas of industry. A well-known product used in the production of American minivan bodies.
In the manufacture of fiberglass products, it is possible to use the "sandwich" technology, when the parts consist of several layers of different materials, each of which meets certain requirements (strength, chemical resistance, abrasion resistance).
The legend of an unknown plastic
Here we are holding in our hands a plastic part that does not have any identification marks on it, no markings. But we desperately need to find out its chemical composition, or at least the type - it is thermoplastic or thermosetting plastic.
Because, if we are talking, for example, about welding, then it is possible only with thermoplastics (adhesive compositions are used to repair thermosetting plastics). In addition, only materials of the same name can be welded, dissimilar materials simply do not interact. In this regard, it becomes necessary to identify the plastic "no name" in order to correctly select the same welding filler.
Identifying the type of plastic is not an easy task. Analysis of plastics is carried out in laboratories according to various indicators: according to the spectrogram of combustion, reaction to various reagents, smell, melting point, and so on.
Nevertheless, there are several simple tests that allow you to determine the approximate chemical composition of plastic and assign it to one or another group of polymers. One of these is the analysis of the behavior of a plastic sample in an open fire source.
For the test, we need a ventilated room and a lighter (or matches), with which we need to carefully set fire to a piece of the test material. If the material melts, then we are dealing with a thermoplastic, if it does not melt, we have a thermosetting plastic in front of us.
Now we remove the flame. If the plastic continues to burn, then it could be ABS plastic, polyethylene, polypropylene, polystyrene, plexiglass, or polyurethane. If it goes out - most likely it is polyvinyl chloride, polycarbonate or polyamide.
Next, we analyze the color of the flame and the smell formed during combustion. For example, polypropylene burns with a bright bluish flame, and its smoke has a pungent and sweet smell, similar to the smell of sealing wax or burnt rubber. Polyethylene burns with a weak bluish flame, and when the flame goes out, the smell of a burning candle is felt. Polystyrene burns brightly, and at the same time smokes heavily, and smells quite nice - it has a sweetish floral scent. Polyvinyl chloride, on the other hand, smells unpleasant - chlorine or hydrochloric acid, and polyamide - burnt wool.
Something about the type of plastic can be said by its appearance. For example, if there are obvious traces of welding on a part, then it is probably made of thermoplastic, and if there are traces of burrs removed with emery, then it is thermosetting plastic.
You can also do a hardness test by trying to cut a small piece of plastic with a knife or razor blade. The chips will be removed from the thermoplastic (it is softer), but the thermosetting plastic will crumble.
Or another way: immersing the plastic in water. This method makes it quite easy to identify plastics belonging to the group of polyolefins (polyethylene, polypropylene, etc.). These plastics will float on the surface of the water, as their density is almost always less than unity. Other polymers have a density greater than unity, so they will sink.
These and other signs by which you can determine the type of plastic are presented below in the form of a table.
P.S. In we will pay attention to the preparation and painting of plastic parts.
Bonuses
Full size versions of images will open in a new window when you click on the image!
Deciphering the designation of plastics
Legend for the most common plastics
Classification of plastics depending on hardness
The main modifications of polypropylene and their areas of application in the car
Methods for determining the type of plastic
You will need
- - a container for melting plastic;
- - soldering iron or soldering station;
- - gas-burner;
- - industrial dryer;
- - welding gun.
Instructions
Before you start melting the plastic, try a small piece of it. Not every type of plastics lends itself to melting in ordinary ones, so it is advisable to find out this during the experiment. Grab a piece of material with tongs or tweezers and bring it to an open or gas burner. The heated plastic will either slowly melt or immediately start burning in the open air.
Once you are satisfied that the plastic can be melted, grind the starting material and place it in a metal container such as a tin can. For the safety of melting the material, insert the container with the shredded plastic into another large-sized container. Pour water into it and put the entire structure on a fire or stove, making a kind of water bath. This method is suitable for processing plastics with a low melting point.
Use a heated soldering iron tip or gas torch to melt small pieces of plastic. If possible, use a soldering station with built-in temperature control for heating the tip. Select the temperature required for melting based on the experiment. Too high a temperature can ignite the material or make the plastic brittle.
Use a welding gun or industrial hair dryer to melt tougher plastics. The procedure for working with a welding gun is indicated in the technical documentation for it. The set also includes filler materials that allow you to weld various types of plastics and plastics, for example, to melt the seams of the products to be joined.
Take precautions when processing plastics with high temperatures. It is advisable to carry out all procedures in the open air in order to avoid poisoning by combustion products. Avoid splashing the melt on exposed parts of the body and clothing to prevent burns and damage to the fabric.
Sources:
- how to process plastic
If any plastic parts break, many try to repair them on their own. However, not everyone succeeds. Since when choosing a joining method, it is necessary to take into account the rheological properties of plastics and their type: easily weldable, difficult to weld or those to which the fusion welding method is generally not applicable.
Instructions
You can use either a semi-professional hair dryer, with smooth temperature and flow control. Additionally, you need welding attachments. To do this, it is necessary to clean both sides of the weld. Select filler rods similar to the material of the fragment. If possible, do a test weld to check material compatibility and to find the correct temperature, blower speed and indentation force. Preheat the hair dryer for 10 minutes to stabilize the hot air.
Fold the fragments of the part and secure in the desired position using special clamps-clothespins. Sharpen the end of the bar to facilitate the initial welding step. Tilt the bar 45 ° while welding, or use the quick welding attachment. The use of the nozzle facilitates the welding process as it has fixed positions for both the bar and the hair dryer. Press down on the bar slightly while working. As a result, you should have a smooth seam that rises slightly above the surface. After complete cooling, it is necessary to grind the seam and paint, if necessary.
Related article
Sources:
- melting plastics
If you need to connect plastic parts together, you don't always need to glue them together. In some cases, you can melt the plastic in the right place to join the plastic, and then combine the parts. When choosing the type of connection, one should take into account the type of material and its ability to be connected by such an improvised welding.
You will need
- - building hair dryer;
- - welding gun;
- - soldering iron (soldering station);
- - filler rod.
Instructions
Determine if the plastic is melt weldable. Plastics can weld easily, with difficulty, or not melt at all. This can be found out empirically. Take a piece of the test material using pliers or tweezers and heat over an open flame. Perform the specified procedure in air to avoid exposure of the respiratory tract to combustion.
If you want to melt a plastic one, cut it into pieces and place it in a saucepan or other container, and then heat over a fire, having made a water bath first. Pour the softened plastic into the mold or treat the seams of the products to be joined with it. In this case, one should not only be careful, but also quickly, otherwise the plastic will harden prematurely.
Use a soldering iron tip to melt the plastic. It is more convenient to use not an ordinary soldering iron, but a soldering station, which makes it possible to regulate the heating temperature of the tip. The required temperature parameters are also selected empirically on pieces of material. If you are careless with the soldering iron, there is a risk of ruining the surface of the plastic or making the seam unnecessarily fragile.
If possible, purchase a special welding machine that melts plastic and various types of plastics. The set also contains samples of material, with the help of which seams and joints are melted. The procedure for use and safety measures for handling it are set out in the instructions for the device.
For some types of plastics, a hair dryer can be used to heat the material to the required temperature. Pre-clean the surfaces to be joined on both sides of the future seam. Select the required nozzle and filler rod. It is advisable to do a test melting of the plastic and how compatible the materials to be joined are.
Warm up the hair dryer to stabilize the temperature. Secure the parts to be melted using a vise or clamps. To speed up the melting process, sharpen the end of the filler rod. Weld the parts by melting them with a hair dryer, while lightly pressing the bar against the surfaces to be melted. After the melt has solidified, treat the weld surface to give it a smooth appearance.
Plastic bottles serve as a universal container for liquids. They have an advantage over glass containers due to their elasticity and larger volume. Plastic containers first appeared in the United States in 1970 and have since become widespread throughout the world.
Plastic products have become an integral part of our lives, so today the topic of plastic recycling at home has gained particular importance. Recycling plastics, even in your own home, contributes to protecting the environment from huge piles of almost non-biodegradable plastic waste.
All plastics are based on polymers (compounds with a high molecular weight and consisting of monomers). Recyclability of plastics depends on the type of raw material from which the plastic product is made. There are many types of plastics these days, which, however, can be grouped into two large groups:
- Thermoplastic. Approximately 80% of plastic products are made from this material. Includes types: HDPE, LDPE, PET, PP, PS, PVC, etc.
- Thermosetting plastic. Presented by polyurethane, epoxy, phenolic resins, etc.
It is impossible to recycle type 2 plastics at home, because thermosetting plastic does not lend itself to re-melting (in some cases, in factories, it is shredded and used as a filler). Thermoplastics, on the other hand, melt when heated without losing their initial properties and, when cooled, regain their original shape. That is why “at home” it is possible to process only thermoplastic plastics with the help of special, but “simple” equipment and to obtain new useful products and materials from such plastic waste.
The most common recyclable raw materials are PET bottles and other plastic containers.
Helpful information! To understand what type of plastic a product is made of, you need to pay attention to the markings applied to its surface (often at the bottom). It has the shape of a triangle, inside which there is a number corresponding to the type of polymer. Also, under the triangle, they put the letter designation of the type of plastic.
What you need for processing at home
Industrial machines that process plastic are expensive and require large areas. Of course, such units are not suitable for implementing the idea of recycling plastic waste at home. To get new products from unnecessary plastic in a handicraft way, you will need to independently design several special machines.
Following the Precious Plastic project
For plastic recycling "with your own hands" you will need the following devices (or one of them, depending on the goal):
- Schroeder. Shreds plastic waste into a specified size crumb, which is then further processed. The device includes several main components: a grinding part, a hopper, a frame and a power source. The most time-consuming stage in the manufacture of the device is the production of a grinding element consisting of a shaft with blades "strung" on it. The hopper is made of sheet metal (waste such as old car parts can also be used here). The required size of the resulting plastic fraction is set using a grid installed under the shredding part.
- Compression device (press). The plastic crumb loaded into the apparatus is subjected to high pressure and high temperature, the result of the process is the production of new compressed plastic products of various shapes. The main elements of the device: furnace, bed, press and electronics.
- Injector ("injector"). The principle of operation of this device is that under the influence of high temperature, plastic chips are melted to a fluid mass, which is then injected into any form. After the plastic mass cools down, new solid objects of small dimensions are obtained.
- Extruder. The heated plastic mass is forced through the channel of the device, as a result of the process, the plastic leaves the device in the form of threads. With the help of an extruder, plastic granules can be produced.
The assembly drawings for all of these devices can be downloaded free of charge from preciousplastic.com. There you can also watch video instructions, in which they clearly and clearly tell about the technologies for creating devices, the necessary materials and the sequence of actions.
The Precious Plastic project is international. Its creator, Dave Hackens, refined drawings of polymer processing devices found on the Internet and, using his knowledge, designed efficient machines that make it easy to make new products from plastic waste. The project helps the common man to create machines that recycle plastic, and with their help, benefit not only for themselves, but also for the environment.
Simple mechanism for cutting plastic bottles
The essence of this cutter is that it cuts threads of a certain thickness from the edge of a plastic bottle (along its circumference). The result is achieved thanks to the fixed blade sliding over the plastic product. The process does not require electrical energy, the device consists only of a holder and a cutter itself. From the plastic threads obtained with your own hands, you can create various interior items, baskets and other objects for which a person has enough imagination.
A few words about safety
Recycling plastics at home does not require supernatural safety knowledge. When melting plastic, you should arm yourself with fireproof gloves (you can use welding gloves) to avoid burns. Also, when working with plastic products, it is important to know that they must not be incinerated, because some types of plastics, when burned, release toxic compounds into the environment. Of course, it is better if shredding plastic waste, melting it, etc. will take place in a specially designated place, for example, in a garage.
Do not forget about safety during the manufacture of devices for the processing of plastic raw materials. It is also necessary to use personal protective equipment here: special goggles, a mask (welding), canvas or leather gloves, etc.
How to melt plastic waste at home
You can melt waste plastics at home using one of the previously described devices (press, injector, extruder). However, their creation requires certain skills and time. You can resort to melting plastic using more primitive methods. For example, a metal syringe and a solid mold can be constructed to produce a plastic screw wing.
Process description
As a raw material, you can use polypropylene (marking "PP"). The crushed material is put into the manufactured syringe and compacted with a metal piston. The syringe filled with plastic is placed in a conventional oven for about 30 minutes at a temperature of 220-240 ° C. Then the molten plastic mass is squeezed out of the syringe into the prepared mold, while holding the material under pressure for some time. After cooling, the finished product can be removed from the mold.
Video of plastic recycling at home
Craftsmen make a variety of products from unnecessary plastic. For information on how plastic molding can be carried out at home to obtain a screw wing, see this video:
You can melt several plastic bottle caps using a building hair dryer. The process of forming useful small plastic products is presented in the following video:
Benefit
The main benefit of self-recycling of plastic is that new products are obtained from unnecessary and cheap materials that are widely used in everyday life and in other areas of our life. Having built special equipment, you can organize a small business based on the manufacture and sale of materials for subsequent processing (for example, flex) or ready-to-use items (plastic dishes, wicker furniture, etc.).
Industrial plastic recycling is associated with a multitude of problems. Recycling plastic waste at home is much easier. It is only important to set a goal for yourself and determine the direction of processing. And it is possible to design plastic-processing devices of any complexity using the “all-knowing” Internet.
Sometimes you can see a picture of how people who like to sit outside in a fire burn disposable plastic dishes, bottles, bags and other garbage left after a fun time. Of course, with this method of disposal of garbage, there is no need to go to the landfill and the forest remains seemingly clean. You can also meet people who use plastic to create crafts and melt it at home. But how harmless is plastic melting and burning?
Everyone should know that it is not safe to burn and melt certain types of plastic!
Many plastic products are marked with a special sign with a number that varies from 1 to 7. Each number corresponds to a specific type of polymer materials, with the exception of 7, which corresponds to all other materials that cannot be attributed to the first 6. Plastics from 1 to 6 refer to, those. they begin to soften when heated. Different types of plastics react differently to fire: some start to smolder, some melt, some barely react.
Most plastics carry the potential hazard of releasing toxic substances associated with the technology of its production and its composition, but there are also safer types among them.
1. PET or PETE (PET) - polyethylene terephthalate
PET is the most common plastic in the food industry and is most commonly used in the production of bottles. It is also a very popular material for creating various crafts. You can find many ways. You can read about industrial PET recycling.
PET melts at a rather high temperature of 260 ° C, but when heated to 60 ° C, PET softens and loses its shape.
Danger:
PET is known to contain antimony and carcinogens. When bottled water is stored, these substances can enter the water, especially when heated. Also, these substances can be released during combustion or melting.
Conclusion:
There is a potential hazard of the release of hazardous substances when burning or melting. There are many ways to create craft PET bottles that do not require heat treatment.
If it is necessary to deform PET, it is better to heat it in boiling water - it is safer than inhaling the vapors from dry heated plastic. Also remember to always work in a well-ventilated area or outdoors.
2. HDPE or HDPE - high density polyethylene or low pressure polyethylene
flickr.com/Tom Magliery / CC BY 2.0 HDPE is the safest plastic. It is best used for making crafts as it is also the easiest to work with. This plastic is used to make bottles for milk and detergents.
Need to know:
It is safe to use HDPE containers or bottles for storing water as nothing leaches out of them. HDPE is a fairly strong plastic and does not "melt", only at VERY high temperatures. This plastic may not be flexible enough, but sometimes it is very good for creating rigid structures.
Conclusion:
This type of plastic can be used without too much concern. Melting of plastic occurs at temperatures of the order of 120-135 ° C.
3. PVS or PVC - polyvinyl chloride, also known as vinyl
PVC is the most dangerous plastic produced to date. Most records are made from vinyl. Despite its danger, many people, unaware of it, heat and burn PVC. The melting point of PVC is 150 - 220 ° C, but it begins to deform at 65 - 70 ° C. You can read about PVC recycling.
Danger:
PVC releases carcinogens as well as lead. When exposed to heat, it releases dioxins, one of the most dangerous pollutants and toxins.
Conclusion:
PVC can be used but heated and burned VERY DANGEROUS!!!
Again, with a strict need for melting PVC is better use boiling water and do not expose it to direct flame. This, of course, must be done in a well-ventilated area.
4. LDPE or LDPE - low density polyethylene or high density polyethylene
flickr.com/ mag3737 / CC BY-NC-SA 2.0 LDPE is another safe plastic. It is used to make buttons in devices, it is also used for production plastic film, grocery bags, trash bags, and some food containers.
What you need to know:
LDPE is a durable material, but less sturdy than HDPE. To melt it, a considerable temperature is also needed - 90 ° C.
Conclusion:
HDPE is a fairly safe plastic to use. Melting requires quite a lot of heat, and you have to be careful - if you want to melt the material, the bags, for example, can easily catch fire.
5. PP or PP - polypropylene
PP is a fairly safe plastic and is used to make various things, such as bottle caps, dispensers, and plastic utensils. It does not melt so easily, its melting point is 160 - 170 ° C, but it heats up quickly. You can read about the recycling of polypropylene in.
Note:
Polypropylene is safe, but some studies have shown that some types of polypropylene can release a biocide. So this material should still be used with caution.
6. PS or PS - polystyrene
Many products are made from this type of plastic, it is used in disposable tableware, packaging, children's toys and in the manufacture of thermal insulation (for example, foam) and other building materials. Hopefully everyone knows to avoid heating styrene foam as it contains styrene. Information on recycling foam can be found at.
The melting point of polystyrene is 240 ° C, but it begins to deform at 100 ° C. When heated, a characteristic odor appears.
Danger:
It releases the most dangerous poison and carcinogen styrene.
Conclusion:
Never heat styrofoam. As a last resort, do this in a well-ventilated area.
7. OTHER or OTHER - miscellaneous plastics not listed above
These plastics include both safe and unsafe plastics. For example, PLA is a biodegradable plastics material that can be handled safely. Polycarbonate (PC) is not as safe and there are studies that show it can release bisphenol A.
Plastics without marking and unfamiliar plastics must be handled very carefully, it is not known what materials they are made of and what potential danger they carry.
You need to burn plastic in a well-ventilated place, preferably outdoors. PVC and PS cannot be burned.
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Types of plastic. Thermosetting plastic and thermoplastic
How polypropylene (PP or PP) is processed