What are the effects of cold weather on urethanes or silicones?

Cold weather will not permanently harm urethane or silicone materials. It will cause these materials to thicken and separate. If a customer tries to use the material while it is cold, it will not cure.

If the material becomes cold, there are two things required to bring materials back to good working condition;

  1. Allow the materials to reach room temperature (at least 73°F/23°C) in the containers before opening. Depending on how long the materials were exposed to cold temperatures, it can take several days to bring them up to 73°F/23°C. 
  2. Urethane or Silicone Rubber - Bring material up to room temperature. Before using, open Part A container and mix thoroughly (3 minutes) with a flat edge stirring paddle before dispensing into a mixing container. Open Part B container and mix thoroughly (3 minutes) with a paddle before dispensing into a mixing container. Silicone curative Part B in glass bottles can be shaken before dispensing. 
  3. Urethane Plastic - Bring material up to room temperature. Trial or 1 gallon units can be shaken thoroughly before dispensing material. 5 gallon buckets should be opened and pre-mixed with a flat edge stirring paddle for 3 minutes before dispensing material.
Disclaimer
This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.