My M4 kit calls for synthetic rubber cement for plastic to metal. I assume this is so you can later remove if necessary. The only one I can find is Ehlmer’s and it has some pretty nasty solvents. I was thinking about using Phenoseal (vinyl adhesive caulk) or Silicone. both are available clear and seem OK for plastic. Any thoughts?
I used Loctite’s “Stik 'n Seal” Waterproof adhesive. It’s clear in color.
I’m not sure how well the caulk would hold up. You might want to test it on some scrap first.