Thx guys for the shared hopes
After 12 hrs of drying, the silicone settled and now leak testing is in progress...No leaks for about hour and a half
(in my experience of making the blocks, they leaked only cos of my impatience to wait for silicone to dry)
Gonna leave them running for a few hours more just to be sure
happyhappyhappy
/edit: got myself a new chuck, the old one started to pi$$ me off, guess inside it the threads are damaged, sometimes it just won't open or close the jaws...that's settled now