At home, with proper safety measures, we can melt plastic for recycling purposes. Not all types of plastic can be melted at home. The most common and less toxic plastics that can be recycled at home are polyethylene and polypropylene, which are found in food packaging.
The most common is to have a portable oven and melt it inside that oven because it should not be done in the same oven where we will later put food.
The plastic must first be shredded, paying attention to the microplastics that should not end up in the garbage. Once crushed, it is added to the mold in which it will be melted and left for a minimum of 20 minutes at a maximum temperature of 190 degrees.
Melt the plastic in the oven
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Place the plastic in a heatproof container. To melt the plastic in the oven, you need a surface that will fit inside the oven and hold the plastic, even when it is melted. Some options are a tray that you will not use for food in the future or a ceramic tile.
– It is important to check that the plastic does not spill onto the surface of the oven if it becomes completely liquid. If this happens, it can be difficult to remove.[1] 2.
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Preheat the oven to about 300°F (149°C). This temperature will gradually melt the plastic. However, you will need to be patient with the melting process. You don’t need a very hot oven to melt most common plastics, such as polypropylene, and you don’t want it so hot that the plastic will burn.[2] In fact, if the heat is too hot, the plastic should be melted.
– In fact, if the heat is too high, the plastic will give off smoke and burn quickly.
3
Ensure that there is adequate ventilation. Even as the plastic gradually melts, vapors are likely to be released into the air. To avoid inhaling them, make sure windows are open and the air is flowing through the area. If you have an exhaust fan, turn it on.
– Also, consider wearing a respirator to avoid inhaling any fumes.
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Watch the plastic as it melts to prevent burning. Turn on the oven light and watch the plastic through the door window. This will help you prevent it from burning, as it should be removed from the oven just as it has melted and before it smokes or burns.
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Remove the plastic from the oven. Use oven mitts to carefully pick up the container the plastic is in. While it is still hot, you can pour it directly into a mold. If you want to cut it into a new shape later, let it cool in the melting container.
– The molten plastic can be put into a mold to shape it. You can use a pre-made heat-resistant one or make your own. If you want to give it a particular shape, it may be preferable to make your own wooden mold.
– The cooled plastic that has hardened can be cut and then polished into the shape you want.
Melt the plastic with a heat gun
- Check if you can melt your plastic safely according to its number of characteristics. There are a wide variety of plastics, and each type has different properties, including the ability to be melted. For example, if the plastic has a number 5 in a triangle, it is a PP-type plastic, also known as polypropylene, which can be heated and then will reconstitute when cooled.
- However, polystyrene foam, which can be identified by its light and airy consistency, will disintegrate when heated. Avoid melting this type of plastic.
- Purchase a heat gun. Heat guns are typically used to remove paint or soften putty but also to melt the plastic. They are available at home improvement and hardware stores. They can also be found in online stores.
- Heat guns typically have low and high settings. The low setting heats to about 500 °F (260 °C), and the high setting heats to about 1,000 °F (538 °C).
- You can rent a heat gun from any home improvement store. However, they usually cost less than $50 (USD), so if you plan to use them several times, it’s probably best to buy one.
- Test a small piece of plastic to see if it melts or disintegrates. Cut a 1-inch (2.5 cm) piece of the plastic and melt it first to test. Heating it and then letting it cool will help you find out if it is thermoplastic or thermoset. Thermoplastics can be heated, and when they cool, they will become solid again. Thermosets will be destroyed by heat and will not be reconstituted in the same way after repeated heating.
- Place the plastic on a heat-proof outdoor surface and put it on your protective gear. Use a surface that can withstand the heat produced by the heat gun. You can use welding blocks, sheet metal or concrete pieces, such as concrete blocks. Then put on gloves and a respirator.
- Placing the plastic on an outside surface will minimize the risk of inhaling fumes as it melts.
- Heating the plastic can release hazardous gases, such as dioxins. To avoid inhaling them, wear a respirator designed to filter these gases.
- Use a sweeping motion to heat the plastic evenly. Plug in the heat gun, turn it on low, and begin heating the plastic. Hold the tip of the heat gun at least a few inches from the surface and move it continuously until the plastic melts.
- If you only want to melt the plastic to smooth or bend it, only a small amount of heat will be necessary. If you want to melt a piece of plastic completely, you must repeatedly go over the surface of the plastic with the heat gun.
- Melt the plastic gradually. Be patient and don’t try to melt the plastic with too much direct heat too fast. Instead, take some time to melt the plastic so that it does not overheat and burn.
- Cover the entire piece of plastic with sweeping motions. This will melt the entire piece of plastic as evenly as possible.
- Place the melted plastic in a mold or let it cool. If you want the plastic to keep its melted shape, for example, if you plan to cut it or polish it to shape, let it cool before you pick it up. If you want to shape the plastic, pour it into the mold while it is still hot.
- Remember to wear gloves when picking up the plastic or the container it is in if it is still hot.