I bought this silicone toilet seat mold off of Amazon. You may want to spray a little bit of releasing agent onto the mold so that the finished seat removes easily once its hardened.
Follow the instructions on the epoxy resin kit to mix the resin and hardener. The brand I used was a 1:1 mix, meaning equal parts of the resin and hardener are mixed together. Stir the mixture well until it is completely blended.
Once you have mixed the epoxy resin, pour it into the mold, filling it to the desired level. Only pour small amounts at a time. Fill about 1/4 inch thickness and let it cure a few hours before adding more.
Allow the resin to cure for at least 24 hours. Be sure to follow the manufacturer’s instructions for curing time. Once the resin has cured, it should be hard and durable.
Once the resin has cured, sand the edges of the toilet seat to make it smooth. Mine actually came out smooth so I didn’t need to sand anything so you may be able to skip this step.