On Tue, 14 Aug 2012 22:39:35 -0700 (PDT), wrote:

I have a couple of things in mind and I would like a source for those BIG toroidal ferrite cores. I can deal with painting the wire and wrapping it because you don't need that many turns. Really I can strip some 10 guage or something, maybe even fatter.

This of course yields what the problem is _ I want like an ID of AT LEAST an inch, a thickness of ¼ inch or better which gives an OD of 1½". The height should be approximately ½ - ¾ inch.

J
Make sure that what you need is ferrite material. Ferrite toroids,
ungapped, have pretty limited use - in pulse transformers, common-mode
chokes, other EMC or damping functions and some saturable circuits.

Ferrite has more applications with other core shapes, where a gap is
more easily permitted.

For most power applications, you'll need a gap of some sort, or
another type of composite material that provides this characteristic
in a physically cut or distributed form - iron dust, MPP/sendust or
others. The descriptions of the latter can be found on Magnetic Inc,
Micrometals and other websites.

The odd iron dust toroidal core size shows up on E-Bay regularly, in
non-auction type sales. Core material can be identified in the part's
type number, and sometimes in the body colour code. Ferrites as well.

What are you building?

RL