I understood ‘hard’ charcoal blocks to be a composite (crushed
charcoal that’s been compressed into a really hard brick) and 'soft’
charcoal to be ‘natural’ charcoal, still in the original form. Right
or wrong, I find both have their uses - I prefer the soft, or natural
charcoal, as it’s easy to make little indentations or poke steel pins
in to hold a piece steady, the hard kind, you can burr out very
precise little indentations for say granulation.
The soft, natural charcoal is quite brittle and can easily break in
two, so it’s important to prepare and protect it - wrap a double
twist of binding wire all round, tighten gently with a twist or two,
and ideally, make your block a little copper tray in which it can sit
all the time. (I’ve seen a good description of this here somewhere a
However, since I acquired my precious BenchMate, I’ve hardly used
either type of charcoal!!