Tufa

A few weeks ago, somebody posted casting techniques that
mentioned a medium called ’ Tufa’. The process sounded much like
Cuttle Fish casting however, the material sounds as though it
might be more durable than cuttle fish. I would really like to
know if this material is available on the open market and if it
is as good as it sounds. Thanks in anticipation.

Brian P Minnear
[In the Antipodes where the temperatures are still above30C]]
   Can tufa be used as a soldering block?  as you would
charcoal? Is it cheaper?  Any advantages?  Just wondering! 
Gini in already hot Fla. 

You probably could use it. maybe it’s cheaper. Dunno. But it
would not offer the nice reducing atmostphere and heat reflecting
qualities of charcoal. And, it’s a bit coarser grained than
charcoal. And I’d guess that a direct flame would start to melt
the stuff… If you’re gonna go that route, then save the cash
or trouble of getting tufa, and go get some decent fire brick.
Cheaper than tufa, and it comes (if you get the right kind) with
a fairly smooth surface… At least that’s my thought on the
subject…

Peter Rowe