"DeepDiver" wrote in message
...
I recently acquired a face mill that has a glossy black oxide surface
finish. The mill is in excellent condition except that the previous owner
allowed it to develop some surface rust (mostly on the upper surfaces;
probably from sitting around uncovered on a shelf). The surface rust is
like
freckles, with most very small, but some spots of 2-3mm dia. Naturally,
the
black oxide finish on these upper surfaces (between the rust spots) is
also
dull.

I was wondering if there is a way to remove the rust (or majority of rust)
without significantly damaging the black oxide. In the past, when I has
some
surface rust on some black oxide impact sockets, I tried the following:

1. Green scotchbrite and kerosene.
2. Phosphoric acid.
3. Salt & vinegar bath.

All three methods removed the black oxide as well as the rust.

How about polishing? That will also remove the black oxide, but perhaps
not
as much. Or is there an easy (and inexpensive) way to renew the finish?

Any advice would be greatly appreciated.

- Michael


Michael,

If the rust is quite superficial, try wiping the cutter with an oily rag,
rubbing on the rested spots. If that doesn't work, a wire brush (hand
variety, not powered) will usually knock the rust off, then you can follow
up with an oily rag. Don't expect it to look like it's never
rusted------the damage is done, it's a matter of degree. Still, this
will make it look one hell of a lot better.

Harold