There are several possibilities on the East Coast that I can think
of right off the bat, that offer ongoing classes: Metalwerx, in
Waltham, MA, and North Bennett Street School, in Boston, MA. NBSS
offers a certificate program; Metalwerx does not.
For workshops: Snow Farm; the New England Craft Program. Metalwerx
also offers workshops.
On the West Coast- Revere Academy.
Hope this is useful,