I am (very slowly) renovating houses on the side to turn them into
rentals - future retirement income. On my current project house, a
pump type soap dispenser began to leak on the edge of the kitchen sink
soon after I bought the house. I ignored the soap scum and pulled the
sink for reuse after I reconfigured the kitchen. Half a year later, I
was ready to reinstall the sink and I tried to clean the soap scum off
and there were half a dozen rust spots (about 3/16 dia) in the
stainless under soap scum. I knocked the red rust down when cleaning
the sink but now I am left with black spots (that I suspect will
return to red rust if they get wet). I have considered trying to buff
the spots (pits?) out with a scotch bright pad on my right angle die
grinder. Anyone have experiance with trying to buff rust out of
stainless? How deep might I need to buff?

wrote:
I am (very slowly) renovating houses on the side to turn them into
rentals - future retirement income. On my current project house, a
pump type soap dispenser began to leak on the edge of the kitchen sink
soon after I bought the house. I ignored the soap scum and pulled the
sink for reuse after I reconfigured the kitchen. Half a year later, I
was ready to reinstall the sink and I tried to clean the soap scum off
and there were half a dozen rust spots (about 3/16 dia) in the
stainless under soap scum. I knocked the red rust down when cleaning
the sink but now I am left with black spots (that I suspect will
return to red rust if they get wet). I have considered trying to buff
the spots (pits?) out with a scotch bright pad on my right angle die
grinder. Anyone have experiance with trying to buff rust out of
stainless? How deep might I need to buff?

On Fri, 25 Apr 2008 05:18:06 -0700 (PDT), wrote:

I am (very slowly) renovating houses on the side to turn them into
rentals - future retirement income. On my current project house, a
pump type soap dispenser began to leak on the edge of the kitchen sink
soon after I bought the house. I ignored the soap scum and pulled the
sink for reuse after I reconfigured the kitchen. Half a year later, I
was ready to reinstall the sink and I tried to clean the soap scum off
and there were half a dozen rust spots (about 3/16 dia) in the
stainless under soap scum. I knocked the red rust down when cleaning
the sink but now I am left with black spots (that I suspect will
return to red rust if they get wet). I have considered trying to buff
the spots (pits?) out with a scotch bright pad on my right angle die
grinder. Anyone have experiance with trying to buff rust out of
stainless? How deep might I need to buff?

You will need to remove all the pitted area and then you will need to
polish the ground/sanded/scotchbrighted area to at least a reasonable
facsimile of the existing sink finish.

Or a quick and dirty way is to use a "stainless passivater" which is
usually hydrochloric acid - the stuff I use is about 20%, which will
remove the corrosion. However, my experience (mostly on boats) is that
the shinier the finish the more "stainless" it is.

You can probably do this with an electric drill with some sort of
spindle to hold the buffing pads if it is a one time project.



Bruce-in-Bangkok
(correct email address for reply)

Since stainless steel doesn't rust the marking should only be on the
surface. In that case you won't need to buff very deep. Of course the
metal isn't very thick so there's still a slight chance of breaking
through.
There's also a chance that what you think is rust isn't and it goes
all the way through.
I don't know about the US but here in UK 2nd hand SS sinks are so
plentiful you can't give them away. I picked up one from my local tip
for £3 ($5) recently.

John

wrote:
I am (very slowly) renovating houses on the side to turn them into
rentals - future retirement income. On my current project house, a
pump type soap dispenser began to leak on the edge of the kitchen sink
soon after I bought the house. I ignored the soap scum and pulled the
sink for reuse after I reconfigured the kitchen. Half a year later, I
was ready to reinstall the sink and I tried to clean the soap scum off
and there were half a dozen rust spots (about 3/16 dia) in the
stainless under soap scum. I knocked the red rust down when cleaning
the sink but now I am left with black spots (that I suspect will
return to red rust if they get wet). I have considered trying to buff
the spots (pits?) out with a scotch bright pad on my right angle die
grinder. Anyone have experiance with trying to buff rust out of
stainless? How deep might I need to buff?

The "rust" is caused by rubbing off the protective coating that forms
from the non-ferrous ingredients in stainless steel, chromium or some
sort of oxides it forms, for instance. What is exposed is the tips of
iron particles, which are now free to rust.
Also, the "stainless steel" does contain some carbon. These carbon
particles can also be exposed by grinding, polishing, etc.. They are black.
So, what you need to do (and this is what another poster talked
about, is to eat up those protruding iron and carbon particles so they
just aren't there any more. Then the "black" goes away since that carbon
particle isn't there any more , and the rust can't form because that
iron particle isn't there any more, either.
Then, after you have applied the whatever-it-is passivating solution,
I guess the chrome oxides or whatever, reform and protect the surface.
So the deal is to come up with a chemical that will eat up the bad
guys without killing you.
No amount of polishing will solve your issue, it'll only get worse as
you uncover more and more of the above mentioned bad-guys.

There's a lot more to it than that. I'm afraid I already built you a
watch, and I don't even know what I'm talking about!
If I got some of this wrong, please,anyone, correct me. This is just my
take on the subject and going through this process several times over
the last many years. Every time I think I understand, then some new
problem comes along.

Personally, I use oxallic acid for this purpose. And I think the stuff
I get (can't find it right now) is something like "Barkeeper's Friend
Stainless Steel Cleaner" which you can get at most grocery stores. Just
check the label to be sure in contains oxalic acid.

"Passivating" is both and art and a science, as I see it. Google it to
see what I mean.

One last thing, for future reference:
NEVER use abrasive materials on stainless steel that have already
been used on "regular" steel. They WILL have some iron particles
imbedded in them that will transfer to your stainless stuff.

Pete Stanaitis
------------------------------------

wrote:

I am (very slowly) renovating houses on the side to turn them into
rentals - future retirement income. On my current project house, a
pump type soap dispenser began to leak on the edge of the kitchen sink
soon after I bought the house. I ignored the soap scum and pulled the
sink for reuse after I reconfigured the kitchen. Half a year later, I
was ready to reinstall the sink and I tried to clean the soap scum off
and there were half a dozen rust spots (about 3/16 dia) in the
stainless under soap scum. I knocked the red rust down when cleaning
the sink but now I am left with black spots (that I suspect will
return to red rust if they get wet). I have considered trying to buff
the spots (pits?) out with a scotch bright pad on my right angle die
grinder. Anyone have experiance with trying to buff rust out of
stainless? How deep might I need to buff?