I found that the silicone pad to seal the heated flask to the vacuum table when pouring was frequently getting scorched and damaged. I started using a piece of heavy cardboard (not corrugated) with a hole in it, soaked for a few minutes before using, and dipped in a bucket of water before pouring each flask. The one in the photo has been used for six flasks. Although it has some marks on it, I expect to use it to pour another dozen flasks before I replace it.
