Polyester resin At first, polyester resin is in a liquid form, with the consistency of jam, but when it is mixed with hardener, after a while, its temperature increases and it turns into jelly, and then it becomes hard and solid. (In Iranian market dialect, the word “polyester” which is the name of a type of fiber, is also used instead of polyester resin.)
– When the polyester hardens, the molecules come together and some of the solution evaporates. As a result, the polyester volume decreases slightly after closing.
– Hardened polyester can no longer be returned to a liquid state (thermosetting plastic)
– The most suitable temperature for working with polyester is twenty degrees.
– The most suitable temperature for working with polyester is twenty degrees.
– Polyester resin sticks to some objects like wood. Therefore, we should take the inside of the mold flat and use separators inside it. We can use paraffin or film. The film is a liquid that is applied with a brush to the surface of the mold and after drying, it creates a thin nylon-like layer.
– Polyester resin should be kept in a cool and dark place. If the resin is of good quality, it can last up to twelve months.
– After closing, polyester becomes strong and non-toxic and is non-porous. It can be filed or drilled with a drill.
– You can mix all kinds of powder colors with polyester resin to make it colorful.
– Polyester resin does not change color in front of light.
– The hardeners used in polyester are available in both liquid and paste forms. The paste type is easier to work with, the liquid hardener is the color of water and has a pungent smell.
The amount of hardener in polyester resin:
By increasing and decreasing the hardener, the hardening time can be adjusted. The general rule of thumb for the amount of hardener in transparent polyester resin is 2%. Polyester resin hardens very slowly in thin layers and the upper part remains sticky. In these cases, the amount of hardener should be increased to 4%.
If the thickness of polyester is high, there is a possibility of cracking, and in this case, the amount of hardener should be selected as 1%. When the mold is plastic and sensitive to heat, the amount of hardener should be reduced. If the amount of hardener exceeds 4%, it will make the polyester too brittle and brittle. In order for polyester to be flexible, the amount of hardener should be 1%.
Accelerator material in polyester resin
Accelerator material is a purple liquid that The amount of accelerator has an effect on the color and time of polyester binding. Many accelerators advance the setting time and cause the polyester to turn yellow or red. The material of acceleration of the handle also affects the generation of heat during closing. When the accelerator is more, more heat is produced due to the acceleration of the polymerization process. When the accelerator is more, more heat is produced due to the acceleration of the polymerization process.
Polyester closing time:
Polyester closing time depends on the amount of accelerator and hardener and room air temperature. The closing time of transparent polyester is longer than the closing time of non-transparent polyester.
The low temperature in the room causes the closing process to be delayed. If the room temperature is below 15°C, the transparent polyester will not harden. In this case, it is said that the polyester is frozen. But non-transparent polyester can harden at temperatures above 12 degrees.
Thin layers of polyester take longer to harden. Polyester continues to harden for several days after closing. Therefore, it should be smoothed after a few days after it comes out of the mold. The duration of polyester binding can be increased to half an hour by placing the statue in the kitchen oven at a temperature of 50 to 80 degrees.
Polyester shrinkage rate:
Different polyesters usually lose between 3 and 5% of their volume during the coagulation time. This property has advantages and disadvantages. Its advantage is that due to shrinking, it comes out of the mold more easily. Its disadvantage is that if we pour one layer of it on another layer that has coagulated, due to the fact that the previous layer has distanced itself from the wall of the mold due to shrinkage, it will enter the space and the volume It creates a surplus that needs to be shaved off later.
Its disadvantage is that if we pour one layer of it on another layer t
, due to the fact that the previous layer has distanced itself from the wall of the mold due to shrinkage, it will enter the space and the volume It creates a surplus that needs to be shaved off later. After the next steps and solidification of the statue, when we take it out of the mold, the statue will have a uniform color. Polyester figurines can also be painted with colored ink. We mix some acetone or instant thinner with the color ink and draw it on the polyester sculpture with a brush. Another color used for polyester is alkyd colors.