Color and polishing

["Clive Murray-White" <cow_artclive@xxxxxxxxxxxxxxxx>]

Dear Jeri,

My expertise is pretty much limited to polishing marble but I think some of
my points will be applicable to you.

I do not favour wax finishes, by my way of thinking they can spoil the
tactile finish, as they can feel waxy to the touch. Ultimately wax is a
fairly temporary way of getting a polished look to your work.

Many waxes actually discolour the marble by adding a yellowish tinge.

After an absolutely thorough and fastidious sanding I use a range of Italian
products that have been created specifically for stone by a company called
TANAX, their polishing compound, a white powder, is probably made from the
finest tin oxide and oxalic acid. You mix this into a paste with water, it
can be applied with either a dampened fabric unshewn polishing buff or by
hand with a damp good quality fabric rag, I like felt best.

I purposely use an old medium speed air drill with my polishing buff for two
reasons, the air tool is not powerful enough to burn the surface and it can
be used quite safely with water.

The principle is the same by hand.

The trick is to make sure that you don't get your work too wet or too dry,
I'd say just damp is best, wet enough so that the paste does not return to
powder and fly away or so wet that it sprays all over you.

Quite quickly your work start to "bloom" don't just press harder when this
happens but bring the surface up to a full almost mirror finish (if that's
what you want) with a couple more applications. With a bit a practice you'll
get it.

There is an unfortunate thing that happens in the polishing process, the
polishing powder gets stuck in any little textural feature that you have, it
can be quite hard to get out, but I have found that plenty of water, even an
old tooth brush and an air gun do a pretty good job.

Some people add finely powdered oxides to their polishing paste so that it
matches the colour of the stone, when it dries it becomes invisible. For my
part I'd always like to know that I'd cleaned it all off.

This polishing paste is much better than any wax. As many of my sculptures
go out in the open air for most of their lives wax is not an option as it
always dries out in the weather. Paste polish actually brings up the natural
surface of the stone.

After a sculpture's surfaces have been completed I apply up to 6 coats of
another TANAX product called Hydrex Idrorrepellente, I would find hard to
really adequately explain what this stuff does - essentially it is a stone
sealer but it is nothing like the stuff you paint on slate floors, its
nothing like varnish, to quote from the can, "it stops microporosities so
that it prevents liquids from penetrating the material but it remains
permeable to vapours letting material breath and keeping their
characteristics unchanged".

Yes it seals it but leaves the surface exactly as if nothing had been done
to it at all.

One can goes an awfully long way. The other very interesting thing about
Hydrex is that it seems to lift out any of the polishing paste that you may
not have got out with water.

One of my assistants, who is always in a hurry to get his work looking
finished uses TANAX  Cera Liquida ( liquid wax) it is a very tempting
product, wipe it on, wipe it off and you have a fabulous polished surface
that does not feel waxy!!

No colour change, no heating and not a lot of heavy rubbing.

I worry a little about the over use of this stuff because I know that it
will not stand up to the weather and there is nothing worse than having to
go back to a client to fix things up. OK for work that goes inside.

I buy mine from a Monumental mason's supplier.

To see what it does click here : http://www.cowwarr.com/CliveMurray-White/
Good luck Regards Clive Murray-White