I'm performing hydrothermal synthesis at 180C/2 hours and safety is questioning my procedure since the stainless steel top loosens some after cooling down. I've followed procedures I've seen online/youtube (as i have no direct contact working with a hydrothermal reactor) so I'm just trying to survey whether this is normal behaviour or if others have found a trick to making sure the top doesn't get loose. My normal process would go for 12 hours so that is where the worry comes into play.