One thing that I don't see mentioned is that carding is used to take the rust coating (more like velvet)off during the rust bluing process. The reason for the fine wire brush is that this must be done with a light touch or the rust under this "velvet" will be removed also which removes the desired black oxide.
The initial process creates a red rust that turns black after boiling. At the stage of carding, it is still fairly easy to rub off the bluing at the corners of a piece.
Thought I might add a bit more detail. There is a lot that I left out but this should make it a bit clearer.
Last edited by Trez Hensley; 02/21/07 11:33 PM.
