Black rust & molasses

Hi folks, I have been using molasses for yonks to remove common old red rust with great success. Tossed a couple of old tools in a small tank a couple of weeks back, had a look after about 8 days and things seemed to be progressing but needed more time. Tossed back; and removed after about another week. About 3/4 of the surface was bright and shiny as usual, but the remainder was covered with a very tough black film that was even resiting the wire brush.

This tough film I think is black rust (magnatite ?) and it seems resistant to the molasses. Has anyone else had a problem like this?

Bruce


Read the full thread at metalworkforums.com...

Black rust & molasses