The amalgam idea sounded interesting until we got to the liquid metal embrittlement issue.
I've followed up on the topic and it sounds horrible - just about the worst-case solution for pitted chambers.

The numerous high-tech epoxy and polymer products all have interesting merits. I have a huge textbook in my library, The Handbook of Adhesives and Sealants

https://www.amazon.com/Handbook-Adhesives-Sealants-McGraw-Hill-Handbooks/dp/0071479163

I tend to refer to this book when I look for such solutions

Amalgam sounded great until it didn't.