How to make liquid plastic with your own hands? Manufacturing technology and scope of the product. Polishing and processing products from PLA, ABS, HIPS, PETG, SBS solvent dichloromethane Does acetone dissolve plastic

Can be performed with various agents: acetone, methyl etiketone, dichloroethane, tetrahydrofuran and dichloromethane. For safety reasons, the use of tetrahydrofuran and dichloromethane for this purpose is preferable, since methyl ethyl ketone or dichloroethane are highly toxic. Acetone is not very good for similar reasons, although it is a very affordable solvent. For materials such as ABS, PLA, HIPS, SBS and other types of plastics, a solvent is used quite often. However, experts recommend D-Limonene as a safer alternative. In addition to safety, this solvent also has a pleasant citrus aroma.

Safety is an important consideration in post-processing, so be aware that some substances, such as dichloroethane, are categorized as powerful poisons and should not be used. Dichloromethane is considered less poisonous, however, it also carries risks to human health. Not very toxic terahydrofuran is almost never found on the free market.

Warning:

The methods of the production process proposed in the article require strict adherence to security measures. Therefore, before performing work, you should carefully read the chapter "Safety when working with solvents", safety data sheets for chemical products.

Post-processing of plastic: the essence and objectives of the process

In the FDM 3D printing process, we get objects with obvious traces of layering (roughness), as well as various artifacts of the production process (traces of points of contact with fasteners and other visible surface defects). Post-processing is used to smooth out uneven surfaces and remove unnecessary artifacts, after which the processed object will look much better.

Solvent Safety Rules

dichloromethane

Since the 19th century, dichloromethane has been classified as a relatively non-toxic and very effective agent for plastics, which has been proven by numerous laboratory studies. But this solvent also has disadvantages. When combined with alkali metals, dichloromethane can cause a violent explosion. The easy volatility of the agent leads to rapid and severe poisoning of the body and damage to a number of important internal organs. Therefore, any work with dichloromethane is recommended to be carried out in the presence of properly working exhaust ventilation.

Do not allow the substance to come into contact with fire or sparks, otherwise a fire may be provoked. Do not pour dichloromethane into a toilet bowl or sink, as the substance does not mix with water and can damage plastic fittings. Dichloromethane strongly resembles acetone and tetrahydrofuran in its properties. It has the same high volatility and hazard class IV. Although the smell of dichloromethane is less pronounced than that of acetone, ventilation of the room should not be neglected.
D-limonene

Among the currently known solvents used for working with plastics, D-Limonene is considered to be less harmful and relatively safe for humans, provided that all precautions are strictly followed. The citrus aroma makes working with the solvent more pleasant. However, it is necessary to take care of good ventilation of the room, as long-term exposure to the substance adversely affects the human body. The D-Limonene soap base makes it easier to neutralize the reaction of the plastic with the solvent, since in this scenario it is sufficient to use soap and water. The only significant drawback of the substance is the fact that it only interacts in HIPS and SBS plastics.

Please note that no matter how relatively safe the solvent is, gloves should be used when working with it and the room should be well ventilated. Gloves will help prevent skin damage or dehydration.

Processing methods

Immersion Processing Method

Immersion treatment is the easiest and fastest method, since one cycle lasts a maximum of 3 minutes. An example is the immersion of Iodine in dichloromethane. The immersion process lasted several seconds, and after a few minutes the solvent completely disappeared from the surface of the object. If you want to get a glossy surface, then the product can be immersed in the solvent again for about half a second. This will be enough so that the solvent is not absorbed and evaporates quickly, and after the operation a glossy surface is obtained.

The duration of the process is very short also because a bath and acetone are not needed for such purposes. For ABS, PLA, HIPS and other rare consumables, dichloromethane is fine. One liter of the product is enough for a long time, the main thing is to maintain the tightness of the container with the solution.

Brush method

Dichloromethane in this case should be applied with a clean brush with natural hair bristles. The substance, by the way, is very volatile, is applied until the surface is completely smoothed at the points of contact between the layers. Dichloromethane is great for applications where selective thinner application is required to leave corners intact and remove obvious imperfections. Practice shows that this method allows you to achieve the best results in the post-processing process. And, of course, do not forget about safety precautions.

In addition to dichloromethane, smooth-on's XTC-3D is very useful for high-quality surface brushing. This material is a protective coating of two elements and is used for high-quality alignment and finishing of 3D objects. During processing, two types of liquid are mixed, and then the mixture is applied to the surface of the product with a brush. The application procedure must be completed within five minutes. Curing occurs within 4 hours, depending on the mass of the object and temperature. XTC-3D has a number of important properties: it allows you to create a hard, impact-resistant coating that can be sanded, primed or painted.

The manufacturer claims that XTC-3D can be used in relation to products obtained using SLA and SLS technology. The substance works great with PLA, ABS, Laywoo, polyurethane foam, wood, plaster, cardboard and even paper. Externally, XTC-3D is similar to ordinary epoxy adhesive, while the substance does not have an unpleasant persistent odor.

Pair Processing Method

Processing with PLA vapor is similar to processing ABS with acetone. Tetrahydrofuran is used as the processing agent. The PLA product to be processed must be placed on an insoluble substrate. For these purposes, you can use aluminum foil or wire mesh. After that, the product is placed in a sealed container. The solvent evaporates when heated and interacts with the surface of the treated object.

In the photo above, the shark tooth is made on a Makerbot Replicator 2 with brown PLA plastic, after which it was treated with tetrahydrofuran and dried.

If you look from above at an uneven surface, you will understand that in post-processing there was a place where the object touched the support. This suggests that before work you need to think carefully about which part and where to lean the product. The calculation of the time for uniform distribution of gas inside the chamber becomes more difficult, the smaller the volume of the working chamber of the printer. The unevenness of the alignment process can be explained precisely by this reason.

Manual polishing method

The manual polishing procedure is familiar to many, and if you do not want to use the pairing method, then you can pay attention to this rather simple and effective method. The solvent will have to be applied to a piece of cloth and polished by hand. For this procedure, use a white or undyed, lint-free cloth. Otherwise, PLA particles will remain on the fabric, and then you will not be able to use it again.

The use of fabric does not exempt you from basic safety precautions. The area should be well ventilated and gloves made of nitrile or neoprene should be worn. The fabric must be wetted with dichloromethane and after that you can start polishing. The result of the work is determined by various factors: how the movements were performed, what efforts were applied, and even how stiff the fabric was. Polishing is usually done in a circular motion unless otherwise specified.

After finishing the polishing procedure, the product must be allowed to dry. In this case, the substance will completely evaporate.

The photo was taken with macro photography, the depth of field is shallow, but the main focus is in order to see the details. The middle part of the tooth was polished. The results were very good. For comparison, pay attention to the left side, where traces of printing are visible.

It should be remembered that the size of the object and the printing parameters determine the amount of effort for polishing. The smaller the product and the higher the print quality, the correspondingly less effort.

Determine the type of plastic

Before gluing plastic, it is important to first determine the type of material of the broken thing. This is important to do in order to better glue the plastic and not spoil the product - many adhesives are solvents for plastic parts.

Most often, the manufacturer labels its products with a recycling symbol, by which you can determine the type of plastic. It is a triangle with traced arrows on the edges, inside there are numbers from 1 to 7.

Another designation of the brand is the letter symbols inside or next to the triangle. Knowing these designations, it is possible to determine the type of plastic, after which the adhesive for plastic is suitable for it.

Marking

1 or PET is polyethylene terephthalate. The main area of application is food packaging. It is used in the manufacture of artificial fibers, plastic packaging for liquid foods, films.

2 or HDPE - high density polyethylene using low pressure technology. It is used in the production of shrink film and packaging bags.

3 or PVC - polyvinyl chloride (PVC) is used in the manufacture of linoleum and plastic windows.

Watch the video to find out more:

4 or LDPE - low density polyethylene using high pressure technology. Food plastic, bags, wrappers and bottles, greenhouse film, packaging containers, toys for children, pipes are made from it.

5 or PP - polypropylene, due to its inertness and heat resistance (it can be kept under hot steam and boiled), is widely used in the production of food packaging. The material is widely used in medicine (disposable syringes, catheters), in the production of household appliances, heat-resistant dishes and plastic pipes for hot water supply.

6 or PS - polystyrene. Disposable tableware (cups for foodstuffs), internal plastic lining of refrigeration devices are made from this type. When foaming expanded polystyrene, a porous insulating material (polystyrene) is obtained, which is widely used in construction and production.

7 or O (Other) - materials that are not recyclable (combine a combination of foil, paper and polymeric materials) or not included in the previous groups.

One way to determine the brand of plastic in the absence of a sign is a burn test. Each material burns in its own way and with a different smell, from which its type can be determined.

Labeling of adhesives

In addition to plastic, adhesives for plastics are marked with symbols, although this designation rarely coincides with recycling marking symbols. To know how to glue plastics, the following letters are affixed to the adhesives to indicate the materials to be glued:

Designation for plastics (click to enlarge)

polycarbonate - PC;
acrylonitrile copolymer - ABS;
polypropylene - PP;
organic glass - PMMA;
polyethylene - PE;
polyvinyl chloride - PVC;
polystyrene - PS;
polyamide - RA 66;
polyurethane - PUR.

Often it does not make sense to look for markings on the packaging of the adhesive, it is enough to study the instructions in Russian, which clearly explains what types of materials the adhesive is intended for and how to glue the plastic.

Types of adhesives

Plastic products have a lot of types and are widely used in everyday life, so gluing plastic can be done with a wide range of adhesives and different methods.

One of the gluing methods is softening the surfaces of the parts to be glued with a suitable solvent (dichloroethane for plexiglass or polystyrene), after joining the seam is reliably soldered. In a similar way, you can prepare glue with your own hands by dissolving plastic small chips.

Types of good plastic adhesives (click to enlarge)

Liquid

Popular household adhesives are easy to use and come in two forms: solvent-based or water-based. The principle of operation of the first is as follows: water or solvent evaporates from the glue applied to the top of the plastic parts, the glue seam dries with further hardening, due to this the parts hold tightly.

These adhesives can bond plastic to porous materials that allow air to pass through, otherwise the water and solvent will not evaporate and the adhesive will not cure.

In everyday life and industry, a good liquid PVA glue is known, which is widely used in furniture production for reliable gluing of artificial films on wooden surfaces; in the construction industry, linoleum is often glued to PVA. Other liquid adhesives are made on the basis of rubber resins, in this case the solvents are methyl acetate, alcohol, acetone.

Contact

The name was obtained because of the principle of gluing: before sticking plastic to plastic, the surfaces of both glued products are smeared with glue and after 10-15 minutes they are firmly pressed against each other. There are two types: with a hardener and without a hardener, the best known brands are BF-2 (4), Moment, rubber glue.

In the video you will learn how to use contact adhesives:

Adhesives include toxic materials, so at home, before gluing plastic, it is necessary to ensure the ventilation of the room.

Reactive Adhesives

There are one-component and two-component types. The former, when applied to the surface to be bonded, harden very quickly from interaction with oxygen or water vapor. These types include the well-known "Second", "Superglue" and other analogues capable of sealing to obtain a rigid and durable seam.

Two-component have a hardener and fixer, which are located separately from each other. Before being used for gluing, they are connected and after being applied to the surfaces to be glued, under the influence of environmental conditions, they gradually begin to harden and glue the parts. Their basis is various resins, the most famous types are polyurethane, epoxy, polyester.

material that is highly resistant to many chemicals and fire.

PVC has a relatively low frost resistance (-15 degrees).

The heat resistance indicator is +65 degrees.

We note several main advantages of the material:

1. does not dissolve in water

2. resistant to the interaction of acids, alcohols, alkaline solutions and mineral oils

3. compatible with some plasticizers.

4. has low flammability and high resistance to oxidation

5. easily soluble in the following substances: ethers, ketones, hydrocarbons (both chlorinated and aromatic)

We are especially interested in the fifth point: the solubility of PVC, namely with what substances this can be done.

Interesting! How to glue PVC panels on liquid nails,

Below are the best means for dissolving PVC.

Solvent for PVC

Based on the above, we conclude that ketones, ethers and hydrocarbons are ideal for dissolution.

This means that it is necessary to use tools that include one of the presented components.

Take away such funds. There is no end in sight to the variety of prices and varieties. We chose two that meet the price-quality ratio.

TetraHydroFuran (THF) is a colorless liquid chemical substance with a characteristic ether odor. Found its application in organic synthesis.

Excellent for dissolving PVC to a paste. Can be purchased at any specialized store.

Cyclohexanone is a clear oily liquid with a pronounced smell of mint and acetone.

The substance in question is a typical representative of ketones, which, based on what was written earlier, is well suited for dissolving PVC.

An interesting video dissolving foam in acetone

Plastic is an organic material based on polymers. The special properties of plastics make it possible to take a certain shape under the influence of pressure and heating, and after cooling to keep it. Sometimes processing of plastics is carried out with the help of solvents. What solvent dissolves plastic? It can be solvent 646, dichloroethane.

As a general rule, dissolving plastics is performed for bonding several different parts of the same material. Such materials include plastics based on polystyrene, polyvinyl chloride and others.

It is best to use solvents. During the treatment of the surfaces to be glued with dichloroethane or solvent 646, a natural softening occurs and very little pressure will be sufficient for gluing.

Before starting the connection, you need to prepare the plastics - degrease and sandpaper. The adhesive should be applied in such a way that the softening is carried out over the entire working surface and a strong joint is ensured. It is recommended to apply the adhesive with a syringe or brush, by dipping or spraying. The parts to be glued should be pressed down and fixed. Pressure must be exerted on both surfaces until a pronounced adhesive layer is visible.

Recently, a lot of new types of solvents have been developed that are less dangerous than dichloroethane. It should be noted that this kind of glue can be prepared by mixing the solvent with plastic shavings. To do this, spray plastic shavings, crumbs or pieces of ABS plastic on a glass or metal can and mix them with WD-40 solvent. The resulting mixture must be mixed and closed with a lid. It must be infused for a day, after which it can be used.

Sometimes acetone is used for finishing (polishing, steaming and even gluing) ABS products. With the same success, methyl ethyl ketone and dichloroethane (both highly toxic) are used for these purposes by some. But tetrahydrofuran and dichloromethane cope best with such tasks, with only one difference - tetrahydrofuran is a precursor and is prohibited for free sale. The solvent is universal and suitable for all types of plastic: ABS, PLA, HIPS, SBS and some others. For smoothing and melting HIPS and SBS, the safest solvent known to us, D-Limonene, is used, moreover, it is harmless, it still smells of delicious oranges. Often used as a flavoring agent.

Remember: dichloroethane is a strong poison. Dichloromethane is less toxic. Tetrahydrofuran - relatively non-toxic, but not freely sold.

When working with this substance, and any chemistry, you need to take serious safety measures. This method is one of several possible processing products.

WARNING:

We describe methods that CAN be used, but which require reasonable precautions. Please read the Safety Precautions chapter, read the chemical safety data sheet, and we will assume that we have warned you.

Why do you need post-processing?

As a result of finishing, irregularities at the junctions of the layers that occur during 3D printing (using the method of layer-by-layer fusing of threads), various kinds of process artifacts (like points of contact with fasteners) and other minor flaws are smoothed out. The part ends up looking less "layered" and more neat. Look at the photos below or google it.

dichloromethane

You can get more information, for example, on Wikipedia. Note: Although it is the least poisonous of the haloalkanes, care must be taken when handling as it is highly volatile and can cause acute poisoning. Work should be carried out with working exhaust ventilation. As far as we know, it is the least toxic solvent for PLA plastic, but great care must be taken when working with it, as the long-term effect of its exposure is extremely dangerous. Flammable, so avoid contact of its vapors with open flames or sparks. The same applies to acetone, tetrahydrofuran, and the like.

Its important property is high volatility. Hazard class IV, same as acetone. Smells much weaker than acetone. All work should preferably be carried out in a well-ventilated area!

Dichloromethane should not be poured down toilets, sinks or other plumbing fixtures, it does not mix with water and plastic pipes in your sewer can be in danger.

D-limonene

Less harmful, we can say safe solvent D-Limonene, strongly smells of citrus. But it only works on HIPS and SBS plastics. We recommend working with it in a well-ventilated area. D-Limonene has an oil base, so to neutralize the reaction of plastic and solvent, they must be washed with soap.

Under whatever circumstances you work with solvents, you should only do this with gloves, because they can quickly dehydrate the skin, which is potentially dangerous. When using strong solvents, it is easy to burn the skin. At the same time, gloves should not be latex (it corrodes latex), but nitrile or neoprene.

The easiest way is immersion processing

Very simple and fast processing, one printout takes no more than 3 minutes. We immersed Yoda in dichloromethane for 1-5 seconds, and over the next 1-2 minutes, the solvent completely evaporated from the surface. To make a glossy surface, dip the part into the solvent for the last time for 0.5 seconds, it will not have time to be absorbed and will immediately evaporate, a candy gloss is provided.

Very fast, no need for a bath, no need for acetone. Dichloromethane is versatile for PLA, ABS, HIPS and possibly many other exotic materials as well. A liter lasts a long time. The tightness of the container for storing the solution is very important.

Brush application

Apply dichloromethane with any clean natural brush until the layers are flattened. This dissolver is extremely volatile, so you won't have to wait long for it to dry. The obvious advantage of this method is that solvent can be applied selectively, leaving sharp corners untouched, and the most noticeable print defects can be treated more carefully. The best processing results are achieved in this way. Take precautions, breathing chemicals is not safe!

Pair processing

The procedure for steaming PLA is essentially the same as for ABS and acetone. Here tetrahydrofuran is used. The PLA object to be processed is placed on an insoluble substrate (aluminum foil, wire mesh, wooden stand, etc.) and placed in a sealed container. When heated, the solvent will begin to evaporate and interact with the surface of the object.

For example, this shark tooth was printed on a Makerbot Replicator 2 with brown PLA, steamed with tetrahydrofuran, and dried.

Notice the unevenness at the top. Here the object touched the support during finishing. Therefore, it is always important to think about what to attach to what part. Also keep in mind that the smaller the volume of your chamber, the more difficult it is to choose the right time so that the gas inside is evenly distributed. Because of this problem, the alignment itself can turn out to be uneven.

Now, a few words about the additional security measures that we promised to mention. All procedures should be outdoors, and tightly close the flask, jar, bottle or other container. Wash the inside of the cabinet before and after use. In short, you need to work carefully and wisely so as not to accidentally burn or explode something.

hand polished

You do not like processing in pairs? Can be polished by hand by applying solvent to a piece of fabric.

The rag should be white (not dyed), lint-free and used only for this purpose, because PLA will accumulate on it and it is no longer suitable for anything else.

Once you have found a suitable cloth, put on nitrile or neoprene gloves, go to a well-ventilated area or outside, and dampen the cloth with dichloromethane. And now with this wet cloth just polish the part. The final result will depend on the direction of your movements, the applied force and the texture of the cloth, i.e. how tough she is. If there are no special reservations, it is best to polish in a circular motion.

Then the object should dry (so that excess dichloromethane evaporates from the surface) - and you're done.

Here is a sample of a polished shark tooth that was printed on a Makerbot Replicator 2 using white PLA.

These photos are in focus. They were taken with macro photography, the depth of field is relatively shallow, so that only the main focus stands out, and you can see the details, although the image is blurred at the edges.

Only the middle of the tooth was polished, what stands out. The photo is not very clear, but it is a very smooth polished surface. Compare it to the left edge, which has not been polished, where you can even see the layers of the printout.

Obviously, the smaller your object, the higher the print resolution (if everything is properly calibrated), the less time you have to spend on fine-tuning to get a well-polished, smooth surface.

In the photo, you can also see that the treated surface is slightly discolored. But here it is in skillful hands. The rag was not quite white, it had some kind of color pattern on it, and the paint reacted with the solvent and at the same time with the plastic.

Addendum: Other Post-Processing Techniques

It should also be noted that PLA is easily finished with ordinary sandpaper. In some cases, it is quite enough to get the surface as it should, especially if you only need to remove traces of the support or similar defects. Stripping is very useful also before chemical treatment. Just go over the problem areas and especially large artifacts with sandpaper, and then proceed as described above. This will save both time, and reagent, and fine-tuning will be more accurate, without significant geometric distortions.

How to glue parts from PLA?

PLA parts can also be glued with a variety of adhesives, we've done well with epoxy and Super Glue, which is really just ethyl cyanoacrylate.

Good luck! Safe work! Smooth printing!

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