While experimenting with making rubber moulds from silicone caulking I bought in Home Depot (not even the good stuff!) I found that the compound adhered to mild steel with indecent tenacity. I had to throw two objects away because the "mould" adhered to them in spite of my best efforts to remove it.
I filed this experience for future reference. If one needed a strong joint of two metal components with some "give", this seems worth considering.
Has anyone used silicone caulking or similar such to join metals?