gold calcite, impregnator, visit studio, website

["John VanCamp" <jvcstnwrks@zzzzzzzzzzzzz>]

Hi Annie,

I'll try to give you a few answers.  First off the acid -
calcite reaction I mentioned is basic High school chemistry.
Mix baking soda and vinegar and watch the fizz!  Any calcite
based stone will react with acid in the same way.  This includes
limestone, Marble (which is metamorphosed limestone),
travertine, and of course your lumps of honey calcite.   As to
just how much damage a particular stone will show over a period
of years depends on a great number of factors, so there is not a
one solution fits all answer.  Acid rain is one culprit, though,
and anything that lowers the ph of naturally slightly acid
rainwater significantly will increase the potential for damage.

The rainwater that drips from an oak tree will be more acid than
that falling in the open field next to the tree. Air pollution
is another factor in increasing environmental acid
levels--particularly pollution containing significant amounts of
sulphur compounds.  And, no two stones react in quite the same
way.  It seems to me that I've read that one can expect about
1/8 inch of environmental erosion per century for Indiana
Limestone.  I have a water feature carved from Indiana in a
location where the pool service company shocked the pool with a
high concentration of muriatc acid, and lost about twice that
much essentially over night.   I do have a number of limestone
sculptures in outdoor locations, and I promise you that I don't
loose any sleep worrying about acid rain damage though.

Now to the deal with sealers.  I have a dear friend in the stone
business who will tell you that the word sealer should be
banished in relation to stone.  The products made for stone are
impregnators which go below the surface, clog up the stone's
porosity, and thus prevent other liquids from entering the stone
and staining it. Some sculptors use bee's wax to do this same
thing, heating the stone and working the wax into the open
pores.   NON-POROUS Stones will not take in an impregnator, and
if the "sealer" is left on the surface all sorts of weird things
can happen. Many marbles along with some of the very compact
limestones fall into this non porous category.  There are
hundreds of products out there now, and my only recommendation
is to test your stone to 1) see if it will take in a sealer, and
2) how it takes the particular sealer you are using.  My
experience has been that different stones react to different
"sealers" in different ways. For example,what works well on
Cordova Crème limestone, can make a mess on Lueders limestone.

No impregnating type sealer can prevent the acid -calcite
reaction since it is a surface reaction, and these product
reside below the stone's surface. The only way to prevent this
type of reaction is to shield the stones surface from the
environment (air, rain, kids with paint cans etc), and I am not
familiar with any product that will do this and still leave a
natural stone appearance. All that I have seen leave that
"plastic" look since that is essentially what they are--Plastic
coatings.

Any way, It is not my intent to scare anyone away from using
calcite based stone for their art.  Quite the contrary. Marble
and limestone are excellent sculpting stones as we all know, and
carvers have known for many many years.  However, calcite based
stones will react with common acids, and that is just the nature
of it.  Soapstone won't, most granite and other igneous
materials won't, alabaster is a stone I'm not familiar with but
I suspect it won't also.  And in spite of what the manufactures
claim, "sealers"are not magic bullets in a can, and not every
stone is a candidate for sealing.

As for your web site questions, I have nothing to offer since I
am in much the same position as you are.  I think I am having
some work done on it now, but haven't spoken to the young man in
who's care it resides for several weeks.
good luck and happy carving
John VanCamp / JVC Stoneworks
PS I don't feel like the list is a place to mention brand names,
so if you email me off of the list, I can give you specific
information on a product that I am well pleased with.