Thermoforming or vacuum forming is the process of heating and shaping plastic. The goal is to create final products using moulds. Examples of thermoforming products are plastic trays and pallets. Heated plastic is called thermoplastic. It is reusable; you may shape it as many times as you want. You may attempt in your kitchen a simplified version of the thermoforming process, with the use of your kitchen oven, some plastic sheets and a mould. You can make a mould out of wood, plaster, epoxy resin or you can simply buy one.
Turn the kitchen oven to 149 degrees Celsius (F). Plastic melts at temperatures from 121 to 204C. You do not need to liquefy the plastic, only to soften the plastic sheet.
Wait for the oven to heat up. Make sure you open the windows in the room you where you are working. Heated plastic is toxic and has sharp odour.
Put a plastic sheet in the oven. Ideally, use a 1/4-inch thick plastic sheet. The most common types of thermoplastic are acryl, polypropylene, polycarbonate and polythene. You may buy any of them in most craft stores. You will achieve same results with any type of thermoplastic.
Turn off the oven and remove the sheet with your hands by using protective gloves. Hold the sheet gingerly on both sides.
Put the softened plastic sheet into a mould. Wait for the plastic to cool. Optionally, you may use a portable chiller to step up the process. If it is cold outside, put the mould on the window sill. Depending on the temperature, the plastic will cool in half an hour to several hours.
Remove particles from the plastic using a clean rag and water.
You may reuse the plastic product you have made. Simply repeat the process to heat it and make another shape. You may do this as many times as you wish. Use plastic painting kit if you wish to paint the product. You may buy one in an art store. Once painted, do not thermoform the plastic product again.
Heated plastic is toxic. Use ventilation and open the windows. Leave the heated plastic to dry on the window sill or outside the house. Do not put the mould with heated thermoplastic into a refrigerator. Always use protective gloves to avoid getting burnt.