Q: I need to bend a thick piece of bronze, but it is too stiff. Any ideas?

A: This will be easier to do if the bronze piece is annealed first. While steel is annealed
by heating to red and being allowed to cool slowly, metals which crystalize in the
"Face-centered Cubic" system- which includes the copper alloys as well as gold and
silver- will reharden if they are treated this way. The crystals, given time, will form a
more organized structure, without the molecular "vacancies" which make the metal
malleable. In fact, one can take advantage of this tendency to "heat-harden" non-ferrous
metals, holding sterling silver, for instance, at 280 degrees C (536 F) for 2 1/2 hours.

To soften metals of this type, they should be brought to a medium red color, then
quenched in water to cool quickly. I would be careful not to overheat it though-
some bronzes will suddenly go from solid to falling-apart when hot. See Tim
McCreight's excellent handbook "The Complete Metalsmith" c. 1991 Davis Publications,
Worcester Mass ISBN 0-87192-240-1 for more details on annealing and hardening, as
well as other aspects of the hand metalworker's craft.

Andrew Werby


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