Klean Clay

Susan White <smwhitewhite [at] aim__com> writes

>I have been using a product called "Klean Clay"
><URL:http://www.kleanklay.com/> for making small
>molds and dams when restoring ceramics and have had no problems
>until recently.  I had thought that this product did not contain
>staining oils; however, when I recently used it on a Greek kylix, I
>found that it did leave a stain on a small area of unslipped
>ceramic.  I was able to remove the stain with mineral spirit
>poultices, but was wondering if anyone else has had this problem
>with this product and/or whether anyone knows if the manufacturer
>has changed the formula and if so, whether anyone knows of a safe
>alternative non-drying clay.

I have the same issue with Klean Klay that I have with people using
fullers earth, which is: You don't know what it is made of.  With
fullers earth you can get a material safety data sheet and at least
find out which of dozens of possible minerals it is.

But Klean Klay has no MSDS on their website.  You'd have to call to
get one, and I can tell you in advance: if you get it, it will not
be very helpful. Klean Klay is a complex mixture whose ingredients
are going to be at least partially withheld as trade secrets or not
divulged because they are not considered health hazards.  But
chemicals which are not regulated as health hazards such as staining
oils and some untested plasticizers can still be damaging to
artifacts.

Not only that, the product comes under the ASTM D 4236 chronic
toxicity labeling standard here in the US which means they can
withhold the identity of, and can call "nontoxic," any ingredient
for which there is no chronic toxicity data!   That's outrageous
considering that there is no long term toxicity data on most of the
organic pigments or on the new phthalates that industry is replacing
the toxic banned ones with.  They are all currently unregulated.

And since it is a commercial product, the manufacturer's formula
will change depending on customer preferences, availability and cost
of various ingredients, changes in manufacturing processes and
equipment, and more.  If earlier batches you used did not contain
staining oils, there is absolutely no reason to assume the current
formulation also does not.

Art conservation is a science.  Conservators are scientists.
Complete treatment records should be kept on everything what was
ever done to, or has come in contact with, an artifact.  No
treatment record should include treatment with an unknown mixture of
chemicals from a product that was not even meant for this purpose.

Monona Rossol, M.S., M.F.A.,
industrial hygienist
Arts, Crafts and Theater Safety, Inc.
181 Thompson St., #23
New York NY 10012-2586
212-777-0062


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                  Conservation DistList Instance 24:26
                Distributed: Thursday, November 18, 2010
                       Message Id: cdl-24-26-001
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