
I think the "blackening" is just a result of starting heating with a colder, yellow, flame. He does the same after working the footing. Reckon this is to avoid breaking through heat-shock.
( , Mon 23 Jul 2012, 23:53, Reply)

also each piece had a little sojourn in the annealing oven so it could relax between being worked.
( , Tue 24 Jul 2012, 0:01, Reply)