snorkack said:
If the goal is casting with easy tools and low temperature, then the obvious nontoxic alternative would be pure tin (without lead alloy component). Or zinc, but zinc is higher melting. Indium has special applications, but is remarkably expensive.
Hmm.. I don't agree. I say no to Tin!
Pretty much all non noble metals not protected by a surface oxide are very toxic! Especially stannous anything! Even the whole thing about replacing lead with tin in PCB solders seems to be a misplaced effort!
The copper content in brass swing door handles often used in older hospitals ensured the death of microbes and many virus in seconds or minutes. Maybe that was just fortuitous, but now, you use a poisonous hand gel instead, and the door furniture is plastic!
Aluminum is so reactive that it forms a transparent self-limiting thickness of oxide in seconds from a clean cut. It is safe to put against the skin. Some say that aluminum adsorption might have links to Alzheimer's symptoms, but I honestly don't know if that is proven, or even plausibly suggested.
Right up to iron, even those oxides, some actually normal, or essential, in human physiology, are toxic when in excess.
I would not even give two cheers for silver if in compound form, and I would not think that black silver tarnish compounds are likely to be benign. Gold, Platinum are maybe not called "noble" for nothing. You are safe with them!
Bismuth has unusually low toxicity among heavy metals, because of the low solubility of bismuth salts, and can be expelled from the body in a few days unless one is being treated with bismuth compounds as medicines, but the substance itself is toxic if it makes it into you as a compound.
Either way - Tin is poisonous! Zinc is poisonous!
https://en.wikipedia.org/wiki/Tin_poisoning
https://en.wikipedia.org/wiki/Zinc_toxicity