You’ll need to create the optimum environment for doming. When using polyurethane resin, the room must be clean, warm and dry.
Make sure the environment is dust and fibre free to prevent contamination of the finished dome.
In order for the resin to flow, cure and form correctly, the temperature should be 25°C (77°F).
High humidity will adversely affect the doming process. Use a de-humidifier if necessary to keep the environment dry with less than 35% relative humidity.