Cathy,

I have many years experience in the conservation of outdoor bronzes
and especially fountains (there seem to be a zillion of them here in
Southern California!:-)

What you have are mineral deposits - probably a great deal of calcium
- that has built up over the years.

Thank you for NOT trying to use CLR or some other home remedy on this,
as you can cause more damage. By nature those cleaners are very
aggressive. Sometimes you need to be aggressive with mineral deposits
but sometimes you do not - and most profressional conservators use a
variety of techniques - and chemical approaches are less favored than
other methods these days (actually just this morning I was testing an
industrial CO2 unit on mineral deposits to see if it will be useful
for a monumental bronze / fountain sculpture treatment coming up in a
few weeks).

It is very hard to give you much in the way of specific advice here,
without knowing more or seeing the sculpture. It sounds like you may
have had this piece conserved at some point in the past - is this
correct?

If the piece was conserved and coated with wax BEFORE the
mineralization happened - then that may provide a nice isolation layer
that will allow the mineralization to be encouraged to depart without
much underlying damage to the bronze substrate - if not, and if you
have very aggressive mineral deposits, then scaling and pitting may
ingress deep into the surface of the bronze - which may necessitate
the cleaning out of the corrosion pits, passivation of active
localized cells, and filling and repatination (worst case scenerio).

Actually I would NOT recommend using distilled water as the cure for
this problem with the fountain. Distilled and deionized water are so
pure that it can easily strip away ions from copper alloys (and other
artifact materials) and there is actually of form of corrosion that is
known as "Erosion" that is seen in metal pipes in industry where pure
water can etch away the metall alloys leading to failure. What you
need is a simple filtering system that will remove the lime, chlorine,
 and other minerals, and maintain a neutral pH, and a system that
recirculates is what most folks with fountains are using today.

I would recommend that anyone with a bronze fountain consider
upgrading to this sort of system so as to reduce the maintainence and
conservation cost and the continual damage to the art (I have seen
some very valuable bronzes by known artists used as fountains)

I would say that in this situation you need a conservator to help you out.

I lived in Denver from 2000 - 2004 where I was the head of Objects
Conservation at the Rockty Mountain Conservation Center at the
University of Denver. If you would like some names of experienced
objects conservators in that region contact me off the list.

I also love to travel too! <grin>

Cheers!
Dave

David Harvey
Conservator
Los Angeles, California



On 6/15/07, cathyosterman <[log in to unmask]> wrote:
> Hi all,
>
> I'm hoping that someone out there has had some experience
> cleaning a bronze fountain. We have a fountain of a cowboy
> dumping water out of his boot and there is a white residue
> around the basin which I would like to clean off. I don't
> know if it is lime deposits or mineral salts but running
> distilled water through the fountain in the future isn't a
> cost-effective solution to the problem for us.
>
> Our maintenance program has included an annual cleaning with
> Orvis soap, a rinse in distilled water, and a waxing with
> Johnson Paste Wax. I believe the last time it was done was a
> year ago. I scubbed at the white residue but it didn't come
> off with the Orvis. There was some CLR with the bronze
> cleaning supplies, but I did NOT use it. I've referenced
> Patrick Kipper's book, "The Care of Bronze Sculpture" but it
> didn't exactly describe how to clean the mineral salts or
> lime off. Is it possible to clean? Should the bronze have
> some patina work done and then be maintained differently?
> Has anyone has a success that they can share with me? Any
> thoughts would be appreciated!
>
> Cathy Osterman
> Curator of Collections
> CFD Old West Museum
> Cheyenne, WY
>
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