During recent renovations to one of our bathrooms, the outside of the WC
bowl has become sprayed with some black dust-like muck which is proving
difficult to remove. We have tried cleaning off with typical bathroom
cleaners but the stuff is reluctant to be come off. What is the most
abrasive "thing" we can apply to a ceramic surface without damaging the
surface itself?

[The origin of this mess is a not known. In the early stages of renovation
I had to remove on old metal shower cabinet which was so "well" built in
that I used an angle grinder with a cutting disc to break up parts of it.
This sprayed some sparks (hot metal) around and looks the most likely
culprit. Only the ceramic has this mess on it. Formica and plaster surfaces
are as clean as ever.]

Frank

On Mon, 13 Dec 2004 10:50:17 -0000, "Frank Stacey"
wrote:

What is the most
abrasive "thing" we can apply to a ceramic surface without damaging the
surface itself?

If it is from an angle grinder nothing will work. The hot spark
melts the thin glass surface on the ceramic and the metal particles
embed themselves into the glass. Over time the particles (if steel)
will rust as well. The Formica and plastic survive somewhat better
as the sparks tend to bounce off them rather than adhere.

If you want to experiment with cures just hold a sheet of glass in
the sparks from an angle grinder to create test panel to try things
on.

I have a very sad tale about a Triumph 2000 windscreen that turned
into an abrasive pad as far as windscreen wipers were concerned after
using an angle grinder on the bonnet.



--
Peter Parry.
http://www.wpp.ltd.uk/

"Peter Parry" wrote in message
...
On Mon, 13 Dec 2004 10:50:17 -0000, "Frank Stacey"
wrote:

What is the most
abrasive "thing" we can apply to a ceramic surface without damaging the
surface itself?

If it is from an angle grinder nothing will work. The hot spark
melts the thin glass surface on the ceramic and the metal particles
embed themselves into the glass. Over time the particles (if steel)
will rust as well. The Formica and plastic survive somewhat better
as the sparks tend to bounce off them rather than adhere.

If you want to experiment with cures just hold a sheet of glass in
the sparks from an angle grinder to create test panel to try things
on.

I have a very sad tale about a Triumph 2000 windscreen that turned
into an abrasive pad as far as windscreen wipers were concerned after
using an angle grinder on the bonnet.


ah, the old triumph 2000 / 2.5 PI. fantastic cars.




RT

In article , "Frank Stacey" f.
says...
During recent renovations to one of our bathrooms, the outside of the WC
bowl has become sprayed with some black dust-like muck which is proving
difficult to remove. We have tried cleaning off with typical bathroom
cleaners but the stuff is reluctant to be come off. What is the most
abrasive "thing" we can apply to a ceramic surface without damaging the
surface itself?

[The origin of this mess is a not known. In the early stages of renovation
I had to remove on old metal shower cabinet which was so "well" built in
that I used an angle grinder with a cutting disc to break up parts of it.
This sprayed some sparks (hot metal) around and looks the most likely
culprit. Only the ceramic has this mess on it. Formica and plaster surfaces
are as clean as ever.]

The black specks are bits of grinding disk and steel that have welded
themselves to the soft ceramic glaze - the only thing I can think of
that might improve the appearance is treating it with some sort of acid
to dissolve the iron component (which will otherwise rust and cause
staining) but I suspect that won't remove all the marks, and even if it
did you'd be left with the little craters that have been burned.

In article , "Peter Parry"
says...
snip.

I have a very sad tale about a Triumph 2000 windscreen that turned
into an abrasive pad as far as windscreen wipers were concerned after
using an angle grinder on the bonnet.

Been there, done that - but it was only the inside of a Mini screen, so
not so important or hard to replace.

Peter Parry wrote:

On Mon, 13 Dec 2004 10:50:17 -0000, "Frank Stacey"
wrote:


What is the most
abrasive "thing" we can apply to a ceramic surface without damaging the
surface itself?


If it is from an angle grinder nothing will work. The hot spark
melts the thin glass surface on the ceramic and the metal particles
embed themselves into the glass. Over time the particles (if steel)
will rust as well. The Formica and plastic survive somewhat better
as the sparks tend to bounce off them rather than adhere.

If you want to experiment with cures just hold a sheet of glass in
the sparks from an angle grinder to create test panel to try things
on.

I have a very sad tale about a Triumph 2000 windscreen that turned
into an abrasive pad as far as windscreen wipers were concerned after
using an angle grinder on the bonnet.


It may be that treatment with brick acid (HCl) will at least get the
iron out of the pits. If that is what it is.

I fear it is.