David, thanks for your caveats. I remember enough of my A Level Chemistry to be aware of some of the dangers. Since the range of temperature that tempering is done is 200C to 320C I’m not looking for a fearsome combination. Mixture 5, half and half sodium nitrate and sodium nitrite, looks like the one. With a melting point of 144C and a working range of 150/500C. Weed killer and food preservative sound like a really technical concotion!

What I am curious about is, will the letting down of a powerful oxidant like sodium nitrate with a stable sodium nitrite reduce some of it’s dangers?

I was rather tickled by Ian S C’s assertion that salt bath work is for the professional workshop. Most of what we do could be so classified.

I do however appreciate every ones concern. I actually picked up on the idea from Workshop Practice Series Number 1 in which Tubal Cain ( the real one) makes it all look perfectly feasible. Ive got a Belling Hot plate and a cast iron glue pot.

What could possibly go wrong?