Drying in epoxy systems occurs in two different ways between coating types and casting types. In coating type epoxy systems, the drying reaction starts and ends homogeneously. In casting types, on the other hand, drying starts locally and ends homogeneously. In other words, in an epoxy casting application of equal thickness, drying starts from the middle of the dense epoxy region and moves towards the edges. In both types, the final hardness is the same in all areas of the epoxy of equal thickness. Only the time to reach this rank will change.
When producing epoxy types, it can be produced in different hardnesses, this hardness level can be in the range of 10-95 in terms of Shore D measure. The hardness values of epoxies are valid up to the maximum temperature resistance level that the epoxy product will reach. A temperature effect on the heat resistance level of a product made of epoxy changes the hardness of the product.
For example: An epoxy product with a heat resistance of 65 C shows 85 Shore D hardness at 25 C room temperature, while a temperature increase to 80 C may cause the hardness to regress to 60-65 levels.
Evaluate the following items in light of this information.
If your epoxy is partially cured and partially liquid remains;
There is a problem with the mixture. Mixing is an important step in epoxy use. Make sure that you have done the details about the mixture correctly. See our article titled “How to Make an Epoxy Mixture”.
If your epoxy is partially cured and partially flexible;
1- It may not be homogeneous.
2- There may be a difference in thickness between the hardened area and the flexible area. Thick surfaces dry early, thin surfaces late.
3- You may have made an early decision. Your drying process may be in progress. In addition to the late drying of especially thick cast epoxies, the use of the product in low thickness will cause it to dry later than normal. In addition, the time specified as the demoulding time corresponds to the initial time of mechanical hardness, not the final hardening time. It is a specified time for the mold to be emptied and prepared for new casting.
If the drying is equal in the whole area but the hardness is very insufficient;
1- Check the hardness value of the epoxy type you have chosen. The product has hardened as it should be, but this value may not be enough for your expectations. In this case, you can work with a different type of epoxy that can dry harder.
2- Check the final hardening time of the type you have chosen. Final hardening is completed in 7-14 days at 25°C room temperature. Wait for this period to complete.
3- Thin casting can be made with thick casting type resin. This may delay the final hardness and you may not even reach the final hardness level at all. For solution, a second layer of thin type resin can be coated on the product.
4- The system may have been in a very cold environment. Epoxies must reach a certain peak temperature value during the reaction. Since the thickness and/or the ambient temperature is too low will prevent the formation of the peak temperature, the final hardness may be delayed and you may not even reach the final hardness level at all.
5- Mixing ratio may not be set correctly. Mixing ratios differ according to epoxy types. This information is available on the label and user manual of the product you are using, please check. You can also get calculation support by clicking the “How Much Epoxy Should I Use” link for mixing ratio.
6- Mixing ratio should be calculated by weight and precision scales should be used when adjusting the mixture. The measurement that should be made by weight with the balance is by eye or glass, syringe, etc. should not be done with volume containers. Due to the negative effect of this situation, your epoxy may not dry completely. “With what to measure the mixing ratio