first question is what do u use for your casting?
second question is dose the cold affect the casting
second question is dose the cold affect the casting
If you mean what material used for the castings then its Clear Polyester Resin, i find this gives much less air bubbles than the General Purpose Resins that are available.
Regarding the second question, yes it certainly does, i have found this out the hard way. I bought one of these from ebay to help with the procedure of my castings.
View attachment 154
Hope this helps ...